RF-Controlled Concert LED Bracelets

This is an unlisted blog post on my RF-Controlled LED bracelets that I'm actively developing. The following consists of captioned photos of the project and a short blurb on where it's going now.

This is the first revision of the PCB, which used a TI Bluetooth chip and had battery holders on the back. There were a few issues with this board, namely that the vias would cause the back of the batteries to short the circuit, and that it was just slightly larger and ticker than what would be comfortable on the wrist after casing was added. This was also the first PCB I ever designed, so it came with a few general schematic mistakes.

This is the second iteration of the PCB, hosting several changes. I moved away from relying on Bluetooth, as my understanding of what's needed for this project has grown dramatically. Now, I'm using OOK at 433.92 MHz, which is perfectly fine for my low datarate and comfortably out of the frequency ranges that concert mics, WiFi, LTE, and other concert interference would be in. The antenna is also now a helical trace antenna, which is cheaper than the chip. Additionally, the new TI MCU is much cheaper (~$1 to ~$0.50), since it doesn't require bluetooth support and can otherwise be low-spec.

Disclaimer: This is the prototype PCB for the final version, with extra resistors and and a U.FL connector.

The TX board and casing for the bracelets is still a WIP. Here is a demo of one of the latest prints for a demo case; it is meant to fit version 1 of the PCB, so is a little larger than what I want in the end.

A final demo of everything working together is coming soon along with a proper blog post for this project!

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