06/14/2021 at 13:31 •
A separate task is going to be designing the battery holder. For now I'm just using an off-the-shelf battery box, with a switch on it, and it's enough for testing, but eventually a separate special design will probably be necessary.
There are two main problems to solve here:
- Since the battery holder will be worn on the back of your neck, it will be in contact with a rather sensitive part of your body — I will need to make sure it's safe for your skin.
- Since it's relatively large and heavy, an ergonomic shape will be necessary.
06/14/2021 at 13:27 •
This is not advertised very much, but CircuitPython can now load GIF files using the Adafruit's Image Load library — I have added GIF support to it a while ago, based on the example code a wrote here: https://github.com/deshipu/circuitpython-gif
However, there is one small technicality: that library doesn't handle animated GIFs.
An animaterd GIF image actually contains multiple images inside, each representing one frame of the animation. They can contain the whole frame, or just the differences from the previous frame, with everything else transparent.
I will need to modify my code to make it read one frame at a time — the SAMD21 microcontroller I'm using probably doesn't have enough memory to read all the frames at once. Hopefully the code will be fast enough to animate the image reasonably well.
If that fails, I might need to include a library written in C to read and display the animations.
06/14/2021 at 13:20 •
I'm still using the same tiny ST7735 color TFT screen, with a new PCB added to the back of it, containing just the microcontroller and a micro-USB socket made of the PCB itself — to make the whole thing as thin as possible. I will probably need to cast it in resin eventually, so it's a sturdy, one-piece thing. For now, for ease of debugging, I'm keeping it separate.
I will need to make at least one more version of that PCB, to include touch pads for switching the image on the pendant.
06/14/2021 at 13:17 •
I haven't touched the #Video Pendant project in a while, but I think it's really time to resurrect it now. CircuitPython has grown a lot in this time, and I also wrote a library that reads GIF files in Python, so there is much that can be improved on the software side.
On the hardware side, I'm going to continue where I left off. I will use the new configuration, with the screen on one end, and the battery holder worn on your back, under the shirt:
This allows the pendant itself to be much smaller, and the battery to be much larger. I will probably switch to a pair of regular alkaline AAA batteries, instead of rechargeable LiPO. They are safer and much easier to get. Also, I don't need to ship them with the device.