Top Five Finish in the Humber Care Tech Challenge

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This was our work area. Keith is posing with a rather nice multimeter. We had the camera in the middle of the table and cupboard (full of sweets), kettle (borrowed jug) and sink (we had everything but the kitchen sink it turned out). The tracking could tell which of the locations you were standing at, and also when you were moving. You can see a horrible, but mercifully short, video of it mostly working here. When the outline flashes white it means that the person has been detected at a location.

Once we had something working it was time to make a presentation in the event that we made “top five” and had to present to the finalist judges. We put together a quick bit of PowerPoint and then dropped it onto my elderly (but still working fine) Surface Pro 3 ready for use.

Turns out we were picked first to present, which was great fun. We didn’t win though, which is not surprising when we saw what the other four teams had been doing. Some lovely presentations, some great ideas and huge chunks of enthusiasm. The winner has a fantastic solution to the issue of “sunsetting”. The great thing about the solution is that the path to deployment is well established and so I’m really looking forward to seeing it go out there. If you’re interested in my horrible code and presentation you can find them on GitHub here. I’m going to have a go at replicating the behaviour using an ESP32 camera.

I’ve put some pictures on Flickr here. They include the all important “firework” shot of the winners getting their richly deserved prize:

Huge thanks to the team for organising another excellent event.

Day 1 of the Humber Care Tech Challenge

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..the tech challenge spaceship is landing…

The Humber Care Tech challenge is becoming a highlight of the year for me. I hope they have one next year. The idea is simple enough: Take a problem faced by healthcare professionals and then turn a bunch of techy folks loose to make things better. This year the theme is patients with Alzheimer and related conditions.

The scope of the problem was nicely illustrated by the range of ideas that have emerged. There are 14 teams here today working away and all of them are working on different aspects of the condition, from creating apps to help carers, to helping with shopping, to building reminiscence systems.

Keith and I are working on a system that tries to track the user performing simple processes. The one we’ve chosen is making a cup of tea. We’ve boiled this down (see what I did there?) to movement between a number of fixed kitchen locations (kettle, sink, cupboard etc) and our application will profile the activity in terms of movement between those locations. Once we have observed sufficient repeats of the activity we can detect changes and also detect when someone is having a bad day.

We are starting with my awesome OpenMV camera with a view to migrating to the ultra-cheap ESP32 Webcams and maybe even a thermal camera.

The Open MV environment is wonderful. I’ve not done much image processing before and this is a perfect way to get started. You write the code in Python and then push it into the camera which then runs it. The library is comprehensive and very easy to use. And it runs really quickly.

I’m trying to keep the algorithm silly simple so that it can be made to run on very constrained devices. Essentially I’m using the camera as a glorified PIR sensor. I’m not very proud of the code that I’ve written, but I’m rather proud of the fact that it seems to work.

Bolt Mystery Solved

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Yesterday I went to a wedding and found a bolt in my trouser pocket. Very strange. Today I remembered why. The last time I wore my suit was at a Humber Care Tech Challenge communications event near the Humber Bridge. Because it was supposed to be posh the suit came out. Then, on the way back I stopped off to buy some bolts for holding air quality sensors to lamp posts. The one in my pocket was the pattern that I took along to make sure that I get ones that match.

M5Stack and M5Stick

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I’ve had a soft spot for the m5stack devices ever since I found them on AliExpress a while ago. They are really well packaged ESP32 based devices with high standards of production and design and a wealth of different add-ons and configurations. I’m on their mailing list and every week they seem to put out something interesting, whether it is a butterfly launcher or a fingerprint sensor. Their prices are at pocket money level for the most part and you can program their devices using Arduino C++, Python or a rather neat system called UIFlow which is block based but actually ends up being Python code.

This is the M5STack unit playing a game of scissors, paper, rock. It’s called an M5Stack because the base unit is 5cm in size. The stack bit is there because units and interfaces can be stacked together.

The M5Stack bit is the unit at the top with the LCD panel and three buttons. This unit is fitted into an M5Stack Faces unit which provides exchangeable face plates. The one shown is the keyboard, but there is also a calculator keyboard and a Gameboy faceplate too which comes into its own when you load up the NES emulator and play some games.

This is the M5Stick. It is even smaller than the stack and has a tiny colour LCD screen (which is presently showing Flappy Bird in play. It has fewer interfaces (although I’ve managed to connect an environmental sensor to it) and just one proper button to press.

Up until now if you wanted some M5Stack goodness you had to buy them from AliExpress, wait for them to arrive and sometimes pay import duty and VAT and sometimes not.

But this week I received an email from Cool Components telling me that they were now stocking M5 products. They are a bit more expensive than buying the devices directly from China, but they do arrive next day and you don’t get any nasty surprises with the price.

If you’re looking for a pleasing device with a lot of flexibility you should take a look at these.

Using Multiple Processor Cores on the ESP32

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Most computers, particularly tiny embedded ones, have a single processor core. This means that they can do just one thing at a time. If you want a computer like this to appear to perform multiple actions at the same time it must execute a tiny “slice” of each action in turn to give the illusion of parallel activity.

However, the ESP32 has two processor cores, which means that it can run two “threads” of execution in the same program code. This has suddenly become very interesting to me, as I don’t want the LEDS to flicker when the computer controlling them has to go off and talk to the network.

It turns out that running tasks on different processors in the ESP32 is actually pretty easy. I used this guide here to get started. Then I slightly changed my program so that the code that drives the leds runs on one thread and the code that talks to the network runs on another.

It just worked. I was amazed. And there was no flicker on the display. One core in ESP32 is continuously running a function that redraws the display and the other core is waiting for network messages.

If you’re wondering how it all works, and whether you can get your hands on the code, I’m going to write a howto and put the whole thing on GitHub really soon.

Scrunching Text

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I’ve actually got my display showing text now. This turned out to be a bit more difficult than I expected. Drawing text was easy, there’s a built in 6x9 font. But of course I wanted a bigger one, so I scaled the text to double size. Then I discovered that, because there are now two pixels between each character, the text wouldn’t fit on the screen. So I rewrote the display code to place each character individually and draw them only one pixel apart. Then I noticed that the redraw was a bit slow and made the display flicker. So I improved the driver to only draw changed characters rather than the entire text. And then I found that characters redrawn in the middle of a line overwrote a part of the characters next to them because they were now one pixel closer than they should have been. So I modified my draw function to redraw all the characters “downstream” of an updated character and put back the missing bits.

And now it works.

And I have another problem. The display is not “fire and forget”. It works because the computer controlling it is continuously clocking the red, green and blue data to turn on each pixel in turn. This means that when the ESP 32 goes off to read the WiFi and get the message to be displayed the whole display falls apart and, if I’m really unlucky, the whole thing crashes.

Oh well. I’ll leave that for tomorrow.