Hello, 

If you have gotten this far you probably know that I intend to build a watch. This is correct. I can also assume that this information alone is not enough to satiate your curiosity, so here I will provide a few cheeky details of my plan. 

Goals

The watch must be:

• Small enough people will not notice that this is 'homemade' from a distance, and sleek enough that people are not repulsed by it when close up. 
• Run on a charge for about 1 year, the same as my current wristwatch. The assumption would be that only the time keeping functions would count towards this, the other features should be pretty intermittently used. Also if you have a long thermal camera session you would expect to charge the device you are using anyway. 
• I want it to be waterproof. This is something that I have not seen in any other DIY watch designs (and few commercial watches with cool features either). This is important as I self identify as "Someone who has a watch", and time without a watch gives me tremendous separation anxiety. Therefore I should be able to wear it in the shower and while washing hands etc. Diving to 100m will remain on the TODO list indefinitely.  
• Be Dumb. I solemnly swear that this project will not become an internet of thing. Nor will it think itself clever enough to have the prefix "smart... " . It will have a predefined list of features, it will do them, and nothing more. No expansion interfaces, no communication. No infinite list of TODOs. Can you remember the last time you 'finished' a project. Me neither. 

Hardware 

You can view the hardware in its unfinished state (Unless you are reading this in the future, in which case, the project is done and the files are gorgeous) here. Currently the hardware is based on 3 main components. Processor: STM32L432, Camera: FLIR Lepton,  Screen: 1.27" OLED ssd1351. 

Additionally to these main components there will be a light sensor for appropriately dimming the display. A UV index sensor, because I am pale and I drink SPF50+ to survive. And some bright LED's for convenient wrist mounted light when you are under a desk renovating a desktop. 

In order to allow the camera to point outward from the user I will be using a flex PCB with rigid sections. There will be 3 parts: the thermal camera pointing out, the watch face on top of the wrist, and the push buttons facing the user.

Software

I will be attempting to use ChibiOS and uGFX primarily. I know that I will need to stretch the STM32 pretty hard to get the Camera read out and the screen update to all meet their timing constraints. Also if I want to run some simple games then having a nice graphics library is nice to have.    

Conclusion

Like / follow etc if you would like to see a watch with a thermal camera integrated.