WPC opto issues…

I’ve had an ongoing issue with my World Cup Soccer ‘94 – at certain times in the game, it will push balls into the plunger lane when it shouldn’t. That points to some sort of problem with the sensing of the balls in the trough at the bottom of the game.

WCS is a WPC – I think that means “William Pinball Controller – and one of the nice features of the software that runs the game is that it has some test software that lets you visualize the state of the switches in the machine:

In my testing, the trough switches work fine when there is a ball in them, but if there is no ball in them, they cycle between open and closed. That is likely to be the problem. I verified that the trough LEDs and opto are functioning correctly and I’ve done the usual “unplug and replug all the cables” approach, so it’s time to dig further.

I did a post on pinside – which yielded no responses – and then pulled out the 7-channel opto board. It looked fine, but when I put a VOM on it, I found 10 VDC and 2.7 VAC. Not good.

I should mention that this machine had some issues on the power driver board, so I took an opportunity to recap it, so I knew that my supply voltage was fine. which meant the most obvious culprit was the 100 uF cap on the opto board.

Except it wasn’t; replacing that caused no real improvement. Which led me back to the power driver board where I found similar voltages at the test point. I pulled the board, found no continuity between the – terminal on C30 and ground, which meant I damaged the through-hold plating with my recap and it just took a while to fail. I added a jumper between the cap terminal and the adjacent ground trace – it would have been trivial to add a trace there, but for some reason they didn’t.

Put the board back in the game, everything works fine. Later I found a note in the WCS repair guide that said, “if the optos are malfunctioning, it’s usually a connection on C30”. Yep.


A self-expanding ESP32 PWM board…

I’ve been working on a little ESP32 expansion board/shield for an LED project I’ve been working on. One of the nice things about the ESP32 is that it has a peripheral known as “LED control” that provides 16 independent channels of PWM for controlling LED brightness, and my project uses that capability.

One of my projects is going to require all 16 channels, so I wanted to do a board that would support 16 channels, but I also wanted a version of the board that would only support 8 channels. I started with the 8 channel board and figured out a way to build a single board that would support 8 channels and also function as an expansion board to add the other 8 channels. I thought the approach was interesting enough to share it here…

Let’s start with a picture of the board:

image

I’m using the 20-pin development board, and it turns out that of the 16 channels supported by the LED control peripheral, half of them are on each set of pins. I started doing an 8-channel version of the controller; you can see the primary pins on the right side of the board that come into the center of the board and then head down into the MOSFET region of the board. That design was fairly simple to do.

Then I needed a way to do something with the 8 channels on the other set of pins. At that point, I realized that if I could use the same board to get the other 8 channels if I flipped the board over:

image

On the primary board, the pins for channels 9-16 on the left side of the board are connected to a header. The ESP32 will be connected to headers on the top side of the primary board, and then we will add a header to the primary board expansion pins – pins 9-16 – on the underside of the primary board.

We will then take a second board and flip it upside down. That puts the header pins that are connected to the MOSFETs on the left side of layout directly under the header on the primary board connected to the expansion pins, so we can just put a complementary header on the expansion board and just stack them together.

Here’s what it looks like in the real world. This is the primary board with headers for the ESP-32 on the left and MOSFETs on the right. That is set up for 8-channel mode.IMG_9631

To enable 16-channel mode, we flip this board over and add some headers. The top header connects to pins 9-16 from the ESP32, and then there’s a single pin on the bottom which connects to ground (if I do a future version I’ll add an extra pin on the left) to provide a bit more support.
IMG_9632

We then take a second board and set it up as an expansion board by adding the complementary headers to it.

IMG_9633

We can then finally stack the expansion board on the back of the primary board and add the ESP32:

IMG_9634

That gives us 16 outputs.

Here’s a short video demo of the controller:

And a second video that show my first project using it:


Happy Zoo Year…

Image result for cougar mountain zoo sign

Traditionally, winter has been the off-season for me. It gets rainy so only about half of the Tuesday/Thursday night rides I schedule actually occur, and we’re skiing on the weekends, so I go from 3 rides a week during the season to 1 ride a week, on average. My fitness slowly decreases and, come March, it takes a lot of effort to get it back.

Last fall I realized – I can be a bit slow at times – that since I was now retired, I had the chance to keep a bit more of my fitness by riding more during the winter on weekdays. And perhaps I could keep my climbing legs as well.

I also realized – well, already knew – that my well-known laziness would be the biggest issue, so I needed a more defined goal. So….

12 Months of Zoo

Was born.

The rules are pretty simple:

The first trip was the Sunday of Thanksgiving week,  November 18th at 1:48PM. The climb took me 34:19, which is pretty much average for me. I also climbed the backside of Summit which is sortof on the way back home and features one of my favorite descents to the north.

December weather is always really hit and miss and we are generally skiing the whole month, but the snow was late so I did a quick ride on Saturday, December 15th in the early morning. 35:52. I added in Pinnacles at the top and a really painful climb off of 164th on the way back.

January, the weather, skiing, and seasonal ennui conspired against me, and it wasn’t until 11:02 AM on January 28th that I made the “JanuZoo” ride, completing it in 35:34.

February 2019 was the snowiest month in Seattle in 50 years. Snowy at my house at 300’ means a lot more snowy at 1300’. Eastside Tours rode a total of zero times for the month, the first shutout I can remember in the 15 years that I’ve been on the ride. It froze overnight and then barely got warm enough during the day.

But between storms on February 21st at 1:01PM, I bundled up and headed out into the mid-40s weather, heartened by the a bit of sun. West Lake Sammamish was cold but not icy, at least none that I saw. I hit Newport and started the climb, with remnants of the last storm still piled up to the side of the road. The road was dry-ish, however, so I kept climbing. Pretty much none of the climb had seen any sun and it all had snow on the side, which pushed the temp down into the mid 30s, but it really wasn’t that bad as I climbed at a lackluster 167 watts. I finished the middle part, and turned onto the top – which sees less traffic – and the snow got higher. A few minutes later, I reached the false summit, descended, and got ready for that last little push to the top.

The road was plowed because there’s a reservoir and antennas up there, but not really very well – there were some clear tracks that were not dry and some snow/ice on the road, and 16-18” on the sides. Hmm. 18-20%, check. Air temp just above freezing, check. Areas of dubious traction, check. And I decided that I wasn’t willing to risk the rest of my ski season and the spring biking season just to ride up a short piece of road. So, I got of my bike and hiked up the damn thing, pushing my bike along with me, for the couple of minutes it took to walk to the top and a 36:41 completion time. And the road was fine, at the top, I clipped back in and slowly and carefully rode down, and quickly found out the real problem. Even unzipping, I get sweaty on the climb and the descents are a field experiment in wind-chill factors. The rest of the ride was the minimal one, just to get home.

With all the issues in February, I decided to hit March early, and on March 13th I headed out at noon and rode both Squak Mountain and Zoo. My ancient Garmin Edge 705 crapped out the week before, so I have no riding data to support this ascent, though I will note that there was about 15” of snow at the top of Squak and I have evidentiary pictures of the top of the Zoo. This is mostly the leftovers from the February storms.

ZooUpZooTop


April 7th brought “A Grand Squaky Zoo”, climbing 3 of the 4 big climbs from Sufferin’ Summits – though not the hardest climbs. The Zoo climb was done in 36:03 and 179 watts on my new Garmin 520 Plus (or is that “+”?).

Sunday, May 5th was Day 1 of minicamp where I rode 5 days straight in a quest to jump-start my fitness. It featured Squak, the extremely painful Telus North climb up James Bush Road, and Zoo in 35:21 at 184 watts.

Sunday, June 9th brought the “3 Biggies” – up Grand Ridge, Squak, and Zoo again. Zoo was dispatched at 32:25 at 208 watts, a nice improvement. And June 29th brought “The Reservoir Rendezvous”, with Grand Ridge, Squak, Telus, Zoo, and Summit. It also brought my slowest trip up at 39:55 and 183 watts, because I was chatting with Douglas Migden from Freemont who is training for the Transcontinental race in Europe doing Zoo. He does Pinnacles at the top rather than the classic top, which doesn’t meet my strict definition of a Zoo climb, but I decided to cut him some slack because he was doing it 6 times that day, plus riding from Freemont and back. My slowness was also attributed to a bout of kidney stones on the 19th, which knocked back my training for a 10 days or so.

Two climbs in June made July pretty obvious, with three climbs as the goal. I did them all in one day in the ZooZooZooSummit ride on July 20th. 38:32 @ 169 watts, 37:30 @ 171 watts, and 34:15 at 191 watts. Disappointingly slower than my early June climb, despite having a group to rabbit after on the third trip up. But 5100’ in 36 miles is pretty good.

There’s something a little embarrassing at this point. I did the triple on the assumption that I had started the year of Zoo in August of 2018 to put an emphatic completion on the year. Then I went back and looked at my data and realized that while I had done serious climbing in both September and October, there were no zoo climbs. Sigh.

August 17th was Sufferin’ Summits 2019. I had managed to squeeze in an abscessed tooth in early August for another week off the bike, and then I pulled a hammie playing soccer on the 11th. My zoo climb was 33:16 @ 193 watts, which was somewhat surprisingly my second fastest ascent of the year despite my time off and my goal to ride slowly on this ride. Hill #5 – which includes “the widowmaker” – was the last one I completed on Sufferin’ Summits (not for the first time).

September 7 brought a “Minimal Zoo”, with 20.3 miles and the flattest route up the zoo and back home. 35:03 @ 180 watts and not feeling very good at all despite starting in the afternoon.

October found me seriously – rabidly even – uninterested with the project, but I pulled on riding clothes for what might be the last jersey/shorts climbing day of the year and headed out. I finished with a thoroughly demotivated – and demotivating – 37:47 @ 169 watts, but finish I did, capping off 15 ascents in the period of 12 months. Here’s a picture facing north. The lake is Lake Sammamish, and off in the distance you could see the Olympics and Mt. Baker if they were available to be seen.

IMAG0417

And thereby completes the cycle of the seasons and the year of the zoo…



Sequence Controller Part 3–Board design and MOSFET testing…

Boards are in the house!

IMG_9608

JLCPCB did a nice job, and the boards look fine. Except:

IMG_9609

Yeah. Those pins are beautifully aligned a very precise 0.1” from where they are supposed to be…

Pro tip: Print out your design and put your components on it so that you can check the design.

Meta pro tip: Follow your pro tips.

Anyway, that’s not the only problem; it turns out that the power and LED parts of the connector are right underneath the end of the board, so you can’t use a normal header on them (you could use a right-angle one if you wanted), so I did a new revision of the board with 1.0” rather than 1.1” for the ESP and extended the board so the connectors are out on the end. That’s on the slow ship from China right now.

Then I did a bit of bodging with some long-tail female headers so I could still do testing.

IMG_9611

Then I put a header for the LEDs and carefully soldered 8 resistors and LEDs to the output pins, so that I have an 8-channel version available for writing software.

IMG_9612

The MOSFETs are pretty darn small, but soldering them was mostly okay. I didn’t bother doing a stencil for this rev so I could reflow, but I will likely do that for the next version.

I have not yet tested what I think is the coolest part of the design; the board is both a main board and an expander board; you can connected a second version of the board on the back of the one with the ESP32 connected to it, and it will get you channels 9-16.

Here’s a quick video of the current state:



Sequence controller test from Eric Gunnerson on Vimeo.

It’s doing a “breathe” on all 8 LEDs with varying timespans for the delay action.

This is the 6th or 7th time that I’ve written sequencing software; there was a Motorola HC11 version, two AVR versions with AC dimming, a 4-channel chaser, and a couple of WS2812 versions.

They were all very simple; take the current state of all the output and drive the outputs to a new state over a given period of time. That works fine, but writing the animation can be annoying and it’s not very compact. This time I wanted to do something different and more elegant:

Here’s my spec:

     IMG_9614

That means ‘loop variable %A from 0 to 7’, and then execute a 100 cycle (1 second) dim of channel %A from its current state to 1.0 (full bright), and then do the same dim back down to zero.

I also wanted to write the vast majority of the code on my desktop, so I took a break and wrote three blog posts about how I do that. It’s basically compile-time dependency replacement with unit tests mostly written using TDD.

Then it was off to writing a *lot* of test code and a lot of classes; 18 difference source files, only two of which are ESP specific at this point. And 15 test classes to drive the tests. It mostly worked great, I did 95% of my coding and only had once latent bug that I had to track down on the ESP32. It was weird one that turned out to have very random behavior. I suspected it was uninitialized data, and that turned out to be mostly right; two subsequent calls to a method used the same stack and I forgot that strncpy doesn’t copy a null. But it all works now. Here’s the code the video is running:

$1$LOOP %B 100:10:-10
    $1$LOOP %A 0:7
        $%B$D%A,1.0
        $%B$D%A,0.0
    $1$ENDLOOP
$1$ENDLOOP”

Variable %B is used to change the cycle count for the operations from 100 to 10 in steps of 10, and then the inner loop cycles through the 8 different outputs. Everything works great.

The code all lives here if you want to see the actual code or a more realistic testing example.

Next steps:

  1. Wireless implementation to do the connection to the ESP
  2. Save and load of the animation
  3. Web interface to edit the animation.
  4. Change the language to move the cycle count into the “dim” command, as it’s not necessary for the loop commands.
  5. Build a second board to test channels 9-16.





Sequence Controller Part 3–Board design and MOSFET testing…

Boards are in the house!

IMG_9608

JLCPCB did a nice job, and the boards look fine. Except:

IMG_9609

Yeah. Those pins are beautifully aligned a very precise 0.1” from where they are supposed to be…

Pro tip: Print out your design and put your components on it so that you can check the design.

Meta pro tip: Follow your pro tips.

Anyway, that’s not the only problem; it turns out that the power and LED parts of the connector are right underneath the end of the board, so you can’t use a normal header on them (you could use a right-angle one if you wanted), so I did a new revision of the board with 1.0” rather than 1.1” for the ESP and extended the board so the connectors are out on the end. That’s on the slow ship from China right now.

Then I did a bit of bodging with some long-tail female headers so I could still do testing.

IMG_9611

Then I put a header for the LEDs and carefully soldered 8 resistors and LEDs to the output pins, so that I have an 8-channel version available for writing software.

IMG_9612

The MOSFETs are pretty darn small, but soldering them was mostly okay. I didn’t bother doing a stencil for this rev so I could reflow, but I will likely do that for the next version.

I have not yet tested what I think is the coolest part of the design; the board is both a main board and an expander board; you can connected a second version of the board on the back of the one with the ESP32 connected to it, and it will get you channels 9-16.

Here’s a quick video of the current state:



Sequence controller test from Eric Gunnerson on Vimeo.

It’s doing a “breathe” on all 8 LEDs with varying timespans for the delay action.

This is the 6th or 7th time that I’ve written sequencing software; there was a Motorola HC11 version, two AVR versions with AC dimming, a 4-channel chaser, and a couple of WS2812 versions.

They were all very simple; take the current state of all the output and drive the outputs to a new state over a given period of time. That works fine, but writing the animation can be annoying and it’s not very compact. This time I wanted to do something different and more elegant:

Here’s my spec:

     IMG_9614

That means ‘loop variable %A from 0 to 7’, and then execute a 100 cycle (1 second) dim of channel %A from its current state to 1.0 (full bright), and then do the same dim back down to zero.

I also wanted to write the vast majority of the code on my desktop, so I took a break and wrote three blog posts about how I do that. It’s basically compile-time dependency replacement with unit tests mostly written using TDD.

Then it was off to writing a *lot* of test code and a lot of classes; 18 difference source files, only two of which are ESP specific at this point. And 15 test classes to drive the tests. It mostly worked great, I did 95% of my coding and only had once latent bug that I had to track down on the ESP32. It was weird one that turned out to have very random behavior. I suspected it was uninitialized data, and that turned out to be mostly right; two subsequent calls to a method used the same stack and I forgot that strncpy doesn’t copy a null. But it all works now. Here’s the code the video is running:

$1$LOOP %B 100:10:-10
    $1$LOOP %A 0:7
        $%B$D%A,1.0
        $%B$D%A,0.0
    $1$ENDLOOP
$1$ENDLOOP”

Variable %B is used to change the cycle count for the operations from 100 to 10 in steps of 10, and then the inner loop cycles through the 8 different outputs. Everything works great.

The code all lives here if you want to see the actual code or a more realistic testing example.

Next steps:

  1. Wireless implementation to do the connection to the ESP
  2. Save and load of the animation
  3. Web interface to edit the animation.
  4. Change the language to move the cycle count into the “dim” command, as it’s not necessary for the loop commands.
  5. Build a second board to test channels 9-16.





Just enough biochemistry – Insulin resistance and Gluconeogenesis

Disclaimer: “Just enough biochemistry” means I’m going to be simplifying what is some very complex biochemistry. Sometimes the omitted details are going to matter.

****

There’s this weird thing that happens as part of insulin resistance that I don’t think gets discussed often enough, and since I think it drives much of what is bad about insulin resistance, I’m going to discuss it here. We’ll start with glucose metabolism:

Elevated blood glucose / elevated insulin

When blood glucose is elevated, the pancreas secretes insulin, and that changes how the body’s metabolism operates:

image

Insulin is a signal to pull excess glucose out of the blood. The body has 4 ways to do this, shown as purple arrows in the diagram. The are, from the right to the left:

  1. Store it as muscle glycogen. There are a lot of muscle cells in the body and the conversion to glycogen is quick, so they can take up a lot of glucose quickly – that is is why the arrow is so big. But their ability to take up glucose is dependent on how much glycogen they already are storing – how much space there is for new glycogen. There be a lot of extra space after a long run and very little space after a few hours watching TV.
  2. Store it as liver glycogen. The liver can’t store quite as much glycogen, but it can still store it pretty quickly.
  3. Burn it as it comes into the bloodstream. The size of this arrow depends on what you are doing; if you are just sitting it’s pretty small, if you are exercising it can be bigger. With high insulin the body will choose to burn more glucose and less fat; notice the small size of the fat arrow.
  4. Convert it to fat. Excess glucose that can’t be handled in the other ways will be converted to fat and stored through a process known as “de novo lipogenesis” (“new fat creation”). The body isn’t very fast at doing this, so this arrow is small. If there is a lot of glucose to convert to fat, this process will take hours.

Broadly speaking, this part of the diagram is about storing glucose energy that is coming in from the diet.

Low blood glucose / low insulin

When blood glucose is low, the pancreas secretes glucagon:

image

When the blood glucose is low, the glucagon is a signal to do something to increase the glucose in the blood.

There are only two sources – outside of eating – to raise blood glucose when it is low:

  1. The glycogen that was stored in the liver previously can be converted back to glucose and released into the bloodstream. This is good for the short term, on the order of a few hours, but at some point the liver will run out of glycogen.
  2. If glycogen stores run low, then the body will convert metabolic leftovers into glucose through a process known as “gluconeogenesis” (new glucose creation). This might be temporary until more carbs are eaten, or it might be continuous if there is little glucose coming through food.

When glucose is rare, the body will try to conserve it, so it will burn proportionally more at; that is why the fat arrow is bigger in this part of the diagram.

There is another process – ketosis – that kicks in when there is little glucose coming in from the diet, but that’s a bit beyond the scope of this discussion.

This part of the picture is about running the body on energy that has been previously stored.

The full picture

Here’s the full picture:

image

This diagram shows how a healthy – insulin sensitive – metabolism works. If you eat a meal that has enough carbs to raise your blood glucose, you will be in the top half of the diagram. Between meals – and especially at night – you will be on the bottom portion of the diagram.


Blood glucose and insulin resistance

One of the tests for insulin resistance/type II diabetes is the Oral Glucose Tolerance Test. In the OGTT a person who has fasted overnight drinks a solution with 50 grams of glucose in it and their glucose level is measured every 30 minutes.

image

This chart shows data from an OGTT for three different people.

Because these people have fasted overnight, we would expect them to have used liver glycogen to keep their blood glucose up for most of the night, and that would leave them with some room to store most of the glucose from the test. If that were true, the glucose could be stored quickly without a lot of blood glucose change and a couple of hours later things would be back to normal. And that is what we see on the “normal chart”.

The discussion about the other lines would typically focus on how much higher the blood glucose levels are and how much longer they take to get back to the starting point, but I want to focus on another factor. Note that the other lines start at significantly elevated blood glucose levels. I find this puzzling; let me explain why…

Looking at the patient with moderate type II diabetes, we see that in a span of 90 minutes, they got rid of a lot of blood glucose, from 280 mg/dl to 170 mg/dl, for a difference of 110 mg/dl. Or something like 70 mg/dl in an hour.

But overnight, they can’t get their blood glucose below 130 mg/dl, despite not eating anything and having 8-12 hours in which it could happen. We would expect that the natural use of glucose would drop the blood glucose to normal levels by morning; in fact, it would drop it too much if the liver didn’t add glucose.

Where is the glucose coming that is keeping that from happening?

That is the puzzle.

Looking back at the diagram, there are only two possible sources for the glucose. Maybe it could come from the glycogen stores, but if that were the case we would expect them to be more depleted in the morning and therefore be able to handle the 50 grams of glucose from the test. That doesn’t appear to be the case.

Which points the finger very strongly at gluconeogenesis.


Gluconeogenesis malfunction

In the diagram, I showed gluconeogenesis on the bottom; it is only active when blood glucose was low and glycogen stores are low.

Unfortunately, when somebody becomes insulin resistance, something gets broken with the regulation of gluconeogenesis. Normally it gets turned off when there is insulin in the system, but that gets broken when there is an accumulation of fat in the liver.

The result is a constant supply of glucose into the bloodstream, with the amount related to how much fat has accumulated in the liver.

What does this mean metabolically?

A constant stream of unexpected glucose means that between meals and overnight, we are depleting our glycogen reserves less. That is the big effect we are seeing in the charts; there is less free room in the glycogen store, so more of the glucose that we eat needs to be converted to fat. That not only means more fat in our fat stores, it takes longer to do this conversion, so our insulin levels are elevated for longer. And any time that our insulin levels are elevated is time when we’re on the upper half of the diagram.. So, more fat stored, less time to burn fat.

Not good. But initially the body is still able to deal with the amount of carbohydrate in the diet and the amount being generated and still keep fasting blood glucose levels normal. It does require more insulin all the time – taking the first step towards hyperinsulinemia – and it will also push up HbA1c levels. That’s why HbA1c is a better diagnostic test for insulin resistance for *most* people than fasting blood glucose. Fasting insulin level is probably better still but is not widely used.

As insulin resistance gets worse, there is more glucose created, enough so the glycogen stores are full most of the time.  Any glucose that can’t be burned off immediately goes straight to fat, and the high insulin percentage – the percentage of time in a day when insulin is elevated – goes up. Hyperinsulinemia gets worse, carbs that are eaten go mostly to fat, and fat eaten goes there as well.

Eventually, the pancreas loses the capacity to produce enough insulin and/or the fat and muscle cells get poor enough at pulling glucose out of the bloodstream, the fasting glucose level goes up, and it’s type II diabetes.

The big point here is that a person who is insulin resistant has different metabolism than one who is not; it’s a bit like they are eating a small amount of candy around the clock.

Diabetes is a chronic disease

For a long time, the ADA recommended high-carb, low fat diets as the only diet for type II diabetes. For people who wanted to lose weight – which is true for most type II diabetics – the recommendation would include a small calorie deficit of around 300-500 calories per day.

What is the impact of that diet for somebody who is insulin resistant and has hyperinsulinemia? We still have the glucose created by the liver and we still have a lot of glucose coming in from the diet, so we’re still going to have the hyperglycemia. As long as the hyperglycemia is there, the insulin is there – we’re on the top half of the diagram – it’s hard to burn fat. So, the body has a few options:

  • Turn down our basal metabolic rate to burn fewer calories.
  • Turn down our optional metabolic activity to burn fewer calories.
  • Convert some protein to energy
  • Try to get us to eat more
  • So, we get cold, tired, hungry, and lose lean muscle mass.

    But we still have the hyperglycemia, insulin resistance, and blood glucose issues.

    This is why type II diabetes is generally considered to be a chronic disease. It’s pretty well known that if people can manage to lose weight, their diabetes symptoms get better, but the prescribed diets are generally ineffective at producing a permanent change. I think that the arrow of causation runs the opposite direction; if you can manage to improve your hyperinsulinemia, you will lose weight.


    Dealing with hyperinsulinemia

    The hyperinsulinemia is at the root of the problem. How can we get the insulin down?

    There’s really only one solution; we need to get the carbohydrates down enough so that the excess glucose produced by the liver is no longer enough to cause significant hyperinsulinemia. If that excess glucose becomes metabolically desirable – necessary to run our bodies – than it will no longer be problematic.

    We need to get back to the bottom part of the diagram. There are a couple of different ways of doing this.

    We could just reduce the amount we eat by a lot. Enough so that the glucose we are eating plus the extra from gluconeogenesis is being put to use to run the body and we don’t need any insulin to store it. We could do this by going on a very low calorie diet, something under 800 calories per day. We could get a gastric bypass, which has a similar effect (gastric bypass also appears to have some additional effect because of the physical changes made). Both gastric bypass and very low calorie diets have good clinical evidence for reversing insulin resistance and getting rid of the symptoms of type II diabetes. Some of the fasting protocols will also likely work, though we don’t have the same quality of studies to support them.

    Or we could just try to reduce the amount of carbs we eat by a lot. So low that we would expect to be relying on gluconeogenesis to produce the glucose that we need and low enough that we don’t have a lot of glucose to process. In other words, a keto or zerocarb diet. And keto diets also have good levels of clinical evidence achieving the result we want.

    With other diets, people get less diabetic and perhaps lose some weight, but still end up diabetic at the end. My assumption is that they don’t do as well because those diets don’t deal with hyperinsulinemia *unless* you convert them to very-low-calorie diets.

    Notes

    As noted, this is a really complex area. For basic biochemistry, there are a number of good references out there; I like “Marks Basic Medical Biochemistry”, which can be found in PDF form online.

    For more of the details, see the following links:

    Insulin resistance and gluconeogenesis

  • Insulin regulation of gluconeogenesis
  • Unraveling the Paradox of Selective Insulin Resistance in the Liver: the Brain–Liver Connection
  • Resolving the Paradox of Hepatic Insulin Resistance
  • Keto diets

  • Virta Health Research Page
  • Virta Spreadsheet of low-carb studies
  • Very-low-calorie diets

  • Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial
  • Very Low-Calorie Diet and 6 Months of Weight Stability in Type 2 Diabetes: Pathophysiological Changes in Responders and Nonresponders
  • Calorie restriction for long-term remission of type 2 diabetes
  • Gastric bypass

    Bariatric Surgery A Systematic Review and Meta-analysis

    Hyperglycemia

    Fasting Insulin vs Hemoglobin A1c: Are We Getting It Right?

    Effect of Physiological Hyperinsulinemia on Gluconeogenesis in Nondiabetic Subjects and in Type 2 Diabetic Patients

    Diabetes and diet

    The Dilemma of Weight Loss in Diabetes



    Write and debug your Arduino programs on your desktop part 3: Fading

    In the first post I said we would be doing a Larson scanner, and all we’ve done so far is make a light that goes back and forth in different colors. That is cool and all, but what about the FADING!

    In standard Larson scanner, this is pretty easily done; you just need a way to go backwards for <n> steps and then you just write the bright color at the current spot and then dim it as you go backwards. With the color wheel, however, you would need to keep track of what the colors of the previous spots were and dim that color.

    Seems like a lot of work to me.

    Instead, we’re going to be building something that I think is a little cooler – a fading LED strip. Set a point to a specific color, and over <N> steps, it will automatically fade to black.

    Hmm. It sounds like what we need is some code that can blend from a color to black. We already have a class that can do that – the ColorBlend class. We can just leverage that to do what we want. Here’s a test:

    static void TestSingleFade()
    {
         FadingLedStrip fadingLedStrip(4);
         LedStrip ledStrip;


        LedColor ledColor;


        fadingLedStrip.setColor(1, 255, 0, 0);


        fadingLedStrip.show(ledStrip);
         ledColor = ledStrip.getColor(1);
         Assert::AreEqual(255, ledColor.Red);


        fadingLedStrip.show(ledStrip);
         ledColor = ledStrip.getColor(1);
         Assert::AreEqual(191, ledColor.Red);


        fadingLedStrip.show(ledStrip);
         ledColor = ledStrip.getColor(1);
         Assert::AreEqual(127, ledColor.Red);


        fadingLedStrip.show(ledStrip);
         ledColor = ledStrip.getColor(1);
         Assert::AreEqual(63, ledColor.Red);


        fadingLedStrip.show(ledStrip);
         ledColor = ledStrip.getColor(1);
         Assert::AreEqual(0, ledColor.Red);
    }

    We set a color and then each time we call show(), it dims the color down. In this case, the dim count is set to 4, so it will take 4 more steps to dim all the way down.

    The code for FadingLedStrip is here:

    class FadingLedStrip
    {
         int _steps;


        ColorBlender _blenders[15];


    public:
         FadingLedStrip(int steps)
         {
             _steps = steps;
         }


        void setColor(int ledNumber, int red, int green, int blue)
         {
             _blenders[ledNumber].blendToColor(LedColor(red, green, blue), 0);
             _blenders[ledNumber].blendToColor(LedColor(0, 0, 0), _steps);
         }


        void show(LedStrip& ledStrip)
         {
             for (int i = 0; i < 15; i++)
             {
                 LedColor ledColor = _blenders[i].getCurrentColor();
                 ledStrip.setColor(i, ledColor.Red, ledColor.Green, ledColor.Blue);
                 _blenders[i].step();
             }


            ledStrip.show();
         }
    };

    It keeps an array of ColorBlenders – one per LED. When we set a color, we tell the blender to immediately switch to that color, and we also tell it to blend to black of the specified number of steps.

    The show() method then walks through all of the blenders and copies the color of each blender to the real strip and tells the blender to step.

    Here’s a video of the final result:


    Larson Scanner from Eric Gunnerson on Vimeo.


    Write and debug your Arduino programs on your desktop part 2: Automated Testing

    Read the previous post before you read this one.

    In the previous post, I showed how to use hand-verification – and perhaps a debugger – to get your code working. That works well in many cases, but sometimes you have code that you think is going to evolve over time or code where it is tedious to do the hand verification.

    The alternate is to automate that verification, using what is commonly known as “Unit Tests”.

    Blending colors

    The current implementation only uses red, green, and blue. It would be much nicer if it could smoothly change between colors. I’m going to be building a way to blend from the current color to a new color in a specified number of steps.

    I’m going to do this implementation in small steps, using a technique where I write the test before I write the code. To start, we need to switch to a new color immediately when the user chooses zero steps.

    Here’s my test code:

    static void TestZeroSteps()
    {
         ColorBlender colorBlender;


        colorBlender.blendToColor(LedColor(255, 0, 255), 0);


        LedColor color = colorBlender.getCurrentColor();
         Assert::AreEqual(255, color.Red);
         Assert::AreEqual(  0, color.Green);
         Assert::AreEqual(255, color.Blue);
    }

    The test blends to (255, 0, 255) – purple – in zero steps, so the next time getCurrentColor() is called, it should return that color.

    The Assert::AreEqual() statements are verifying that the values we get back are the ones we expect; if they are not, a message will be written out to the console.

    This test code lives in the ColorBlenderTest.h file.

    The code for ColorBlender lives in the arduino project, and looks like this:

    class ColorBlender
    {
         LedColor _targetColor;


        public:


        LedColor getCurrentColor()
         {
             return LedColor(_targetColor.Red, _targetColor.Green, _targetColor.Blue);
         }


        void blendToColor(LedColor targetColor, int steps)
         {
             _targetColor = targetColor;
         }
    };

    When run, that produces no errors. In the next test, we’ll do the blend in one step. Here’s a new test:

    static void TestOneStep()
    {
         ColorBlender colorBlender;


        colorBlender.blendToColor(LedColor(255, 0, 255), 1);


        LedColor color = colorBlender.getCurrentColor();
         Assert::AreEqual(0, color.Red);
         Assert::AreEqual(0, color.Green);
         Assert::AreEqual(0, color.Blue);


        colorBlender.step();


        color = colorBlender.getCurrentColor();
         Assert::AreEqual(255, color.Red);
         Assert::AreEqual(0, color.Green);
         Assert::AreEqual(255, color.Blue);
    }

    The initial color should be black, and then after calling step(), it should move to the new color. When this is run, we get the following:

    Assert: expected 0 got 255
    Assert: expected 0 got 255

    We get those errors because there is no implementation to make the test work. This code will make it work:

    class ColorBlender
    {
         LedColor _currentColor;
         LedColor _targetColor;


        public:


        LedColor getCurrentColor()
         {
             return LedColor(_currentColor.Red, _currentColor.Green, _currentColor.Blue);
         }


        void blendToColor(LedColor targetColor, int steps)
         {
             _targetColor = targetColor;


            if (steps == 0)
             {
                 _currentColor = _targetColor;
             }
         }


        void step()
         {
             _currentColor = _targetColor;
         }
    };

    and now, onto two steps. Here’s the test:

    static void TestTwoSteps()
    {
         ColorBlender colorBlender;


        colorBlender.blendToColor(LedColor(255, 0, 255), 2);


        LedColor color = colorBlender.getCurrentColor();
         Assert::AreEqual(0, color.Red);
         Assert::AreEqual(0, color.Green);
         Assert::AreEqual(0, color.Blue);


        colorBlender.step();


        color = colorBlender.getCurrentColor();
         Assert::AreEqual(127, color.Red);
         Assert::AreEqual(0, color.Green);
         Assert::AreEqual(127, color.Blue);


        colorBlender.step();


        color = colorBlender.getCurrentColor();
         Assert::AreEqual(255, color.Red);
         Assert::AreEqual(0, color.Green);
         Assert::AreEqual(255, color.Blue);
    }

    and the updated code:

    class ColorBlender
    {
         float _red = 0.0F;
         float _green = 0.0F;
         float _blue = 0.0F;
         float _redDelta = 0.0F;
         float _greenDelta = 0.0F;
         float _blueDelta = 0.0F;


        LedColor _targetColor;


        public:


        LedColor getCurrentColor()
         {
             return LedColor((int) _red, (int)_green, (int)_blue);
         }


        void blendToColor(LedColor targetColor, int steps)
         {
             _targetColor = targetColor;


            if (steps == 0)
             {
                 _red = _targetColor.Red;
                 _green = _targetColor.Green;
                 _blue = _targetColor.Blue;
             }
             else
             {
                 _redDelta = (_targetColor.Red – _red) / steps;
                 _greenDelta = (_targetColor.Green – _green) / steps;
                 _blueDelta = (_targetColor.Blue – _blue) / steps;
             }
         }


        void step()
         {
             _red = _red + _redDelta;
             _green = _green + _greenDelta;
             _blue = _blue + _blueDelta;
         }
    };

    That works. One more test to add; we should stop blending even if we go beyond the specified number of steps. Here’s a test for it:

    static void TestThreeStepsAndHold()
    {
         ColorBlender colorBlender;


        colorBlender.blendToColor(LedColor(10, 0, 0), 3);


        Assert::AreEqual(0, colorBlender.getCurrentColor().Red);
         colorBlender.step();


        Assert::AreEqual(3, colorBlender.getCurrentColor().Red);
         colorBlender.step();


        Assert::AreEqual(6, colorBlender.getCurrentColor().Red);
         colorBlender.step();


        Assert::AreEqual(10, colorBlender.getCurrentColor().Red);
         colorBlender.step();


        Assert::AreEqual(10, colorBlender.getCurrentColor().Red);
    }

    That fails on the last assert, as it keeps adding and gives us 13. I added some code and ended up with this:

    class ColorBlender
    {
         float _red = 0.0F;
         float _green = 0.0F;
         float _blue = 0.0F;
         float _redDelta = 0.0F;
         float _greenDelta = 0.0F;
         float _blueDelta = 0.0F;


        LedColor _targetColor;
         int _steps;


        public:


        LedColor getCurrentColor()
         {
             return LedColor((int) _red, (int)_green, (int)_blue);
         }


        void blendToColor(LedColor targetColor, int steps)
         {
             _steps = steps;
             _targetColor = targetColor;


            if (steps == 0)
             {
                 _red = _targetColor.Red;
                 _green = _targetColor.Green;
                 _blue = _targetColor.Blue;
             }
             else
             {
                 _redDelta = (_targetColor.Red – _red) / steps;
                 _greenDelta = (_targetColor.Green – _green) / steps;
                 _blueDelta = (_targetColor.Blue – _blue) / steps;
             }
         }


        void step()
         {
             if (_steps != 0)
             {
                 _red = _red + _redDelta;
                 _green = _green + _greenDelta;
                 _blue = _blue + _blueDelta;
                 _steps–;
             }
         }
    };

    All of that was written without and tested without any interaction with my microcontroller.

    Doing something nice with the blender…

    The blender by itself isn’t that useful; we need something to drive it through different colors. Here’s ColorWheel.h:

    class ColorWheel
    {
         int _stepCount;
         ColorBlender _colorBlender;
         LedColor _colors[6] = {
             LedColor(255, 0, 0),
             LedColor(255, 255, 0),
             LedColor(0, 255, 0),
             LedColor(0, 255, 255),
             LedColor(0, 0, 255),
             LedColor(255, 0, 255) };
         int _colorIndex = 0;


        public:
             ColorWheel(int stepCount)
             {
                 _stepCount = stepCount;
                 _colorBlender.blendToColor(_colors[_colorIndex], 1);
             }


            LedColor getNextColor()
             {
                 _colorBlender.step();
                 LedColor ledColor = _colorBlender.getCurrentColor();
                 if (_colorBlender.isDone())
                 {
                     _colorIndex = (_colorIndex + 1) % 6;
                     _colorBlender.blendToColor(_colors[_colorIndex], _stepCount);
                 }


                return ledColor;
             }
    };

    It uses a ColorBlender, and whenever a color blender is done – which is checked through a new “isDone()” method – it will add a blend to the next color in the sequence. So it continuously cycles through the 6 main colors (Red, yellow, green, cyan, blue, purple).

    It has tests:

    #pragma once
    #include “..\Arduino\Larson\src\ColorWheel.h”


    class ColorWheelTest
    {
         static void TestSingleStepWheel()
         {
             ColorWheel colorWheel(1);
            
             LedColor ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(  0, ledColor.Green);
             Assert::AreEqual(  0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(255, ledColor.Green);
             Assert::AreEqual(  0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(  0, ledColor.Red);
             Assert::AreEqual(255, ledColor.Green);
             Assert::AreEqual(  0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(  0, ledColor.Red);
             Assert::AreEqual(255, ledColor.Green);
             Assert::AreEqual(255, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(  0, ledColor.Red);
             Assert::AreEqual(  0, ledColor.Green);
             Assert::AreEqual(255, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(  0, ledColor.Green);
             Assert::AreEqual(255, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(  0, ledColor.Green);
             Assert::AreEqual(  0, ledColor.Blue);
         }


        static void TestFourStepWheel()
         {
             ColorWheel colorWheel(4);


            LedColor ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(0, ledColor.Green);
             Assert::AreEqual(0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(63, ledColor.Green);
             Assert::AreEqual(0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(127, ledColor.Green);
             Assert::AreEqual(0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(191, ledColor.Green);
             Assert::AreEqual(0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(255, ledColor.Red);
             Assert::AreEqual(255, ledColor.Green);
             Assert::AreEqual(0, ledColor.Blue);


            ledColor = colorWheel.getNextColor();
             Assert::AreEqual(191, ledColor.Red);
             Assert::AreEqual(255, ledColor.Green);
             Assert::AreEqual(0, ledColor.Blue);
         }


    public:
         static void RunTests()
         {
             TestSingleStepWheel();
             TestFourStepWheel();
         }
    };

    and that makes the Animater simpler. Here’s the running code:

    #define NUM_LEDS 15


    class Animater
    {
         int _last = 0;
         int _current = 0;
         int _increment = 1;


        int _color = 0;
         ColorWheel _colorWheel;


        public:


        Animater() : _colorWheel(20) {}


        void doAnimationStep(LedStrip &ledStrip)
         {
             ledStrip.setColor(_last, 0, 0, 0);
             LedColor ledColor = _colorWheel.getNextColor();


            ledStrip.setColor(_current, ledColor.Red, ledColor.Green, ledColor.Blue);
             ledStrip.show();


            _last = _current;
             _current = _current + _increment;


            if (_current == 0 || _current == NUM_LEDS – 1)
             {
                 _increment = -_increment;
             }
         }
    };









    Write and debug your Arduino programs on your desktop

    Working on projects with an Arduino – or with other microcontrollers – can be a lot of fun. It can also be a frustrating experience; you write some code and then you need to wait for it to be compiled, packaged up, downloaded to your microcontroller, and then run. And when it doesn’t work, it can be difficult to figure out why it isn’t working; generally, the best you can do look at the output from Serial.println() or look at the signals on an oscilloscope, if you own one.

    As a (now former) professional developer, I was sure that there was a better way, and after some experimentation I came up with the method described in these posts.

    Basically, the approach is pretty simple. We are going to structure our software so that there are two discrete parts; a first part that is directly dependent on the microprocessor and libraries and a second part that is generic. The second part will contain the bulk of the code that we will be writing.

    And then, we are going to use a generic C++ environment to run the code from the second part and verify that it works. Once we have it working in that environment, we can then move over to the arduino environment and test it on the real hardware.

    In addition to making it easier to write and verify code, this will also break our code into parts and make it simpler to understand.

    Tools

    We will be using two different development environments. For our Arduino code, we need an Arduino environment – what I would call an “IDE”. I’m going to be using Visual Studio Code with the Platform IO package, but you can use the Arduino IDE if you’d rather. Both of those are free.

    We will also need a desktop/laptop environment that can run C++ code. There are several good options here; I’m going to stay true to my roots and use Visual Studio Community with C++ support installed (also free) for that development, but you can use whatever environment you would like.

    The project

    A quick look at my blog will indicate that I am quite devoted to LEDs, so that’s what we’re going to build. Specifically a Larson Scanner:

    Or at least something like that; I’m not sure we’re going to get to the dimming trail part. If you want to follow along, you’ll need a microcontroller that can run the FastLed library (I’m going to use an ESP8266 board), and a strip of WS2812/Neopixel LEDs. There’s a nice intro to using FastLED in their wiki here, and I suggest getting something working in your environment using their directions before trying to follow along.

    I’ll add a note here that if you are using the ESP8266, Makuna’s NeoPixelBus is a better choice than FastLed as it has hardware support, but FastLed is more popular so that’s why I’m using it here.

    First Version

    All of the code lives in the LarsonScanner repository. I will try to keep my commits small and informative so you can see what the changes are.

    I started by writing a quick and minimal version of the code. It looks like this:

    #include <Arduino.h>
    #define FASTLED_ESP8266_NODEMCU_PIN_ORDER
    #include <fastled.h>


    #define NUM_LEDS 15
    #define DATA_PIN 3


    CRGB leds[NUM_LEDS];


    void setup() {
       FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
    }


    int last = 0;
    int current = 0;
    int increment = 1;


    void loop() {
      leds[last] = CRGB::Black;


      leds[current] = CRGB::Red;
       FastLED.show();
       last = current;
       current = current + increment;


      if (current == 0 || current == NUM_LEDS – 1)
       {
         increment = -increment;
       }


      delay(30);
    }

    Most of this is boilerplate FastLED code. The code itself is simple; it has three variables:

    • current defines the next LED that we need to turn on
    • last defines the LED that is currently on that we will need to turn off
    • increment defines the direction we are moving with the animation

    The loop code sets the previous LED off and turns the new one on, and then increments to move to the next LED. If that puts us at the ends of the strip – either LED 0 or LED NUM_LEDS-1 – then that tells us we need to start going the other direction and we negate increment to do that.

    Running this code on the desktop

    Our goal is to be able to run the code that we wrote – the code to do the animation – on the desktop. But we can’t do this because that code calls the FastLED library, and there’s no FastLED library on the desktop. What we will need to do is provide a way for our animation code to *use* the FastLED code indirectly rather than referring to it directly.

    In software development terms, we’re doing what is called “encapsulation”; taking all of the code related to a specific operation and separating it from the rest of our code.

    We will take all the FastLED code and move it into a separate class. It looks like this:

    #define FASTLED_ESP8266_NODEMCU_PIN_ORDER
    #include <fastled.h>


    #define NUM_LEDS 15
    #define DATA_PIN 3


    class LedStrip
    {
         CRGB _leds[NUM_LEDS];


        public:
         void setup()
        {
             FastLED.addLeds<NEOPIXEL, DATA_PIN>(_leds, NUM_LEDS);
         }


        void setColor(int ledIndex, int red, int green, int blue)
         {
             _leds[ledIndex] = CRGB(red, green, blue);
         }


        void show()
         {
             FastLED.show();
         }
    };

    This new class now keeps track of the details of dealing with FastLED. Note that the “leds” array has been renamed “_leds”; that is a naming convention to make it easier to know that it belongs to this class.

    Our main code now looks like this:

    #include <Arduino.h>
    #include <LedStrip.h>


    LedStrip ledStrip;


    void setup() {
       ledStrip.setup();
    }


    int last = 0;
    int current = 0;
    int increment = 1;


    void loop() {


      ledStrip.setColor(last, 0, 0, 0);
       ledStrip.setColor(current, 255, 0, 0);
       ledStrip.show();


      last = current;
       current = current + increment;


      if (current == 0 || current == NUM_LEDS – 1)
       {
         increment = -increment;
       }


      delay(30);
    }

    Better. There are no FastLED details in here, but there are still arduino details that would get in the way of using it from the desktop. Just as we took all the FastLED details and put them in a class, we will now put all of the animation details into a separate class. It looks like this:

    #define NUM_LEDS 15


    class Animater
    {
         int _last = 0;
         int _current = 0;
         int _increment = 1;


        public:


        void doAnimationStep(LedStrip &ledStrip)
         {
             ledStrip.setColor(_last, 0, 0, 0);
             ledStrip.setColor(_current, 255, 0, 0);
             ledStrip.show();


            _last = _current;
             _current = _current + _increment;


            if (_current == 0 || _current == NUM_LEDS – 1)
             {
                 _increment = -_increment;
             }
         }
    };

    That puts all the code in a method named doAnimationStep; we pass in an LedStrip, and it does whatever it needs to do.

    Our main program code gets even simpler:

    #include <Arduino.h>
    #include <LedStrip.h>
    #include <Animater.h>


    LedStrip ledStrip;
    Animater animater;


    void setup() {
       ledStrip.setup();
    }


    void loop() {
       animater.doAnimationStep(ledStrip);
       delay(30);
    }

    This demonstrates quite well why encapsulation is a good thing; instead of having one main program with different things going on, we have three sections of code; the code that only deals with FastLED operations, the code that deals with the animation, and then a very simple bit of code that hooks them together. If your arduino code is getting complicated and hard to understand, using encapsulation will help immensely.

    The desktop version

    We are now ready to run our animation code. I’ve created a Visual Studio C++ project named “ConsoleTest” next to the arduino project. My goal is to run the code in Animater.h in this environment, and to do that, I’m going to need a different implementation of LedStrip.h. Here’s what I create in the ConsoleTest project:

    class LedStrip
    {
    public:
         void setColor(int ledNumber, int red, int green, int blue)
         {
             printf(“LED %d: (%d, %d, %d) \n”, ledNumber, red, green, blue);
         }


        void show()
         {
             printf(“Show: \n”);
         }
    };

    Instead of talking to an LEDStrip, it just writes out the information it is called with to the console.

    The ConsoleTest.cpp file in this project looks like this:

    #include “stdafx.h”
    #include “LedStrip.h”
    #include “..\Arduino\Larson\src\Animater.h”


    int main()
    {
         LedStrip ledStrip;
         Animater animater;


        for (int i = 0; i < 30; i++)
         {
             animater.doAnimationStep(ledStrip);
         }


        return 0;
    }

    It includes the printing version of LedStrip in the test project, but it then includes Animater.h from the arduino project. The main() function then calls the animation code the same way the arduino code would call it. It generates the following output:

    LED 0: (0, 0, 0)
    LED 0: (255, 0, 0)
    Show:
    LED 0: (0, 0, 0)
    LED 1: (255, 0, 0)
    Show:
    LED 1: (0, 0, 0)
    LED 2: (255, 0, 0)
    Show:
    LED 2: (0, 0, 0)
    LED 3: (255, 0, 0)
    Show:
    LED 3: (0, 0, 0)
    LED 4: (255, 0, 0)
    Show:
    LED 4: (0, 0, 0)
    LED 5: (255, 0, 0)
    Show:
    LED 5: (0, 0, 0)
    LED 6: (255, 0, 0)
    Show:
    LED 6: (0, 0, 0)
    LED 7: (255, 0, 0)
    Show:
    LED 7: (0, 0, 0)
    LED 8: (255, 0, 0)
    Show:
    LED 8: (0, 0, 0)
    LED 9: (255, 0, 0)
    Show:

    We are now able to see the calls the animation code would make to the FastLED library when it runs on the arduino and see if it is behaving as expected.

    Digression for experienced developers

    If you aren’t an experienced developer, you can safely ignore this section.

    This technique – which I call “abstraction by include file” – likely looks a little weird. The “right” way to do this in C++ is to define a pure abstract class named ILedStrip with pure virtual functions that are then overwridden by LedStrip in the arduino code and by a LedStripTest class in the console project.

    I’ve implemented this technique both my way and the “right” way, and I’ve found that the right way requires an extra interface definition and doesn’t really help the resulting code. And it requires understanding virtual methods. But that’s an aesthetic choice; feel free to make the opposite choice.

    Modifying our animation…

    Let’s say that we now want our animation to change colors each time it switches direction. Can we write that code and test it without downloading it to the Arduino?

    Here’s my crappy implementation:

    #define NUM_LEDS 15


    class Animater
    {
         int _last = 0;
         int _current = 0;
         int _increment = 1;


        int _color = 0;


        public:


        void doAnimationStep(LedStrip &ledStrip)
         {
             ledStrip.setColor(_last, 0, 0, 0);
             if (_color == 0)
             {
                 ledStrip.setColor(_current, 255, 0, 0);
             }
             else if (_color == 1)
             {
                 ledStrip.setColor(_current, 0, 255, 0);
             }
             else
             {
                 ledStrip.setColor(_current, 0, 0, 255);
             }
             ledStrip.show();


            _last = _current;
             _current = _current + _increment;


            if (_current == 0 || _current == NUM_LEDS – 1)
             {
                 _increment = -_increment;


                _color = _color + 1;
                 if (_color == 3)
                 {
                     _color = 0;
                 }
             }
         }
    };

    Basically, it has a color variable that increments each time we switch directions, and we check that variable to decide what color to set.

    By examining the output, we can see if the program is doing what we expect. Or we can use the debugger that is built into Visual Studio Community to have the program stop at any line in our code so that we can see what the values of variables are and what code is being executed. That is much much easier than trying to figure out what is going on in code running on the arduino. There’s a nice introduction to using the debugger here.

    Tracking state

    To verify an animation, we have to read a lot of output and keep track of which LEDs are which colors. We can make that a little easier by modifying our test LedStrip class so that it keeps track for us. First, we’ll need class that can hold the state of one LED:

    class LedColor
    {
    public:
         int Red;
         int Green;
         int Blue;


        LedColor() : LedColor(0, 0, 0)
         {
         }


        LedColor(int red, int green, int blue)
         {
             Red = red;
             Green = green;
             Blue = blue;
         }
    };

    And then we can use that class in our LedStrip class:

    class LedStrip
    {
         LedColor _colors[15];


    public:
         void setColor(int ledNumber, int red, int green, int blue)
         {
             _colors[ledNumber] = LedColor(red, green, blue);
         }


        void show()
         {
             printf(“Show: “);
             for (int i = 0; i < 15; i++)
             {
                 printf(“(%d,%d,%d)”, _colors[i].Red, _colors[i].Green, _colors[i].Blue);
             }
             puts(“”);
         }
    };

    This generates the following output:

    Show: (255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)
    Show: (0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(0,0,0)(255,0,0)(0,0,0)(0,0,0)(0,0,0)

    I find this approach to be a bit more visual and easier to understand.

    That’s a good place to stop for this post. The next post will explore automated testing using this approach.


    Part 2: Automated testing


    Sequence Controller Part 2–Board design and MOSFET testing…

    Having chosen MOSFETs, I went off to do some board design. I’m hoping this will be a very simple design; it needs to provide power to the ESP, connect ESP outputs to the driving MOSFETs, and provide connections for the loads to the MOSFETs.

    Here’s the schematic:

    image

    On the right we have all of the LOAD outputs; we’re using N-channel MOSFETS to switch to ground, so there are 8 outputs plus a ground. Somewhat conveniently – assuming I’ve read the data sheets right – there are 8 PWM outputs on the right side and 8 on the left.

    In my WS2811 extender I put both positive and negative terminals for the load on the board, but in this case I don’t have room so only the ground connections show up.

    The other two 9-pin connectors – ExtOut1 and ExtIn1 – are for a feature that I’m hoping will be very cool, but it will be oh-so-easier to explain when I have boards in hand.

    One question I already had was whether the ESP could put out enough current to switch the MOSFETs quickly enough. The time spent switching is time the MOSFETs spend in their linear region, and the Rds is much higher during that period. The SOT-32 package doesn’t give much opportunity for heat dissipation.

    I didn’t have any protoboards to mount the MOSFET on, but I did have some WS2812 LED boards that I made. Two of the solder pads matched and I used a short wire to hook on the third one.

    IMG_9584

    That’s wired up to the ESP.

    IMG_9582

    The ESP running very simple code that ramps up to full brightness and then back down.

    I then needed a test load. I don’t actually have a good 2-3 amp 5V test load, so this was my first test:

    IMG_9581

    That’s 5 of my ornament kits stacked on top of each other. At full brightness they are pulling just over an amp, which is my design point (more would be better). I let it ran on that for a few hours, and the MOSFET was maybe a little warmer than ambient, but barely. I threw on my 12V light bulb testing rig, and got 1.5 amps, and it was also fine with that. Two of those bulbs in parallel would unfortunately be 4 times the power which is more than the MOSFET is rated for, so I’ll need a different load to finish my testing.

    I am a little concerned that the ESP may have issues driving more than 1 channel as there could easily be 8 (or 16) channels trying to change all at once. The ESP has 16 independent PWM channels and I’m thinking that if I desync the frequencies slightly (say, 500 Hz, 501 Hz, etc.), the transition points for the PWM will generally not be at the same time.

    Anyway, I considered that enough of a test to do the board design. I had to do a custom component and footprint for the ESP because I couldn’t find one that matched my 30-pin DEVKIT board.

    One of these times I’m going to remember to do a video of the layout process, but I usually enjoy it so much that I don’t remember.

    image

    The MOSFETS live at the bottom to minimize the length of the traces that carry the most current, and to put them all near the bottom. The high-current traces are 1mm wide; I could likely go to 1.5 or even 2mm but that seems like a bit of overkill for the currents I expect. The driving traces from the ESP are 0.5mm because I want to get charge into and out of the gates as quickly as possible.

    There is a bit of creativity on the left side; the pins on the 9-pin connector are quite a bit offset from the ones on the ESP, so I took pin 12 and 13 and ran them up to the two top pins to make the rest easy to layout.

    The board is meant to be an “undershield”; I plan on putting female headers in the 15 pin connectors of this board and those will mate with the male headers that are already on the board. The power and load connectors should probably use right-angle headers.

    I spun a small order of these boards for testing.






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