solder and wifi

Hi everyone !

I haven’t posted in a long time (yeah, I know), but I’ll try to make up for it by depicting what I did since then.

This week-end, after finding the north with the Bosch sensor, it was all about crafting the ball ! Clement and I started to solder the LEDs ribbons on the surface of the shell. Unfortunately, we weren’t very good at it and it took us far too much time for a little progress. The other Clement and Artur turned out to be way better at this. They crafted the ball at the beginning of the week as I took the matter of Wi-Fi in hand.

The goal was to be able to notify the ball but let it perform other network operations at the same time. I wanted to make a TCP server and generate an interruption on a GPIO for the program to be notified. It would then scan the active connections looking for data to be read, parse it, and decide what to do with it.

And yes, this approach winded up as a real nightmare ! Fortunately, I got tipped by Sam and did something much simpler: the program opens a websocket on a server, and waits for a message. Those have a command on the first line and some data on the second one. What I did for the LEDs is that the data is a URL where a binary image awaits to be downloaded and loaded on the LED SPI bus. Well, it works way better like that ! So I started with a Django server, but this framework is a bit too high-level to do Comet. I switched to Node.js, fooled myself trying to use socket.io on a JS-uncapable chip, and finally made it with this cool library. I now can listen to the server, get the URL, download the image, and display it on the ball !

So now I’ll probably make a tiny UI to ease testing. 🙂

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