Built this double ESP32 device to help me extracting data out of an SD card and into Home Assistant
This weekend I connected two ESP microcontrollers over SPI using custom embedded firmware and the result is something I’m pretty proud of.
The device bridges two completely separate WiFi networks simultaneously. One side connects to my CPAP writes therapy data to an SD card and exposes it over a secured local WiFi. The other side connects to my home network, where a server endpoint receives that data in chunks.
In between, the two microcontrollers talk over SPI synchronized, clocked, back-and-forth in milliseconds. One picks up the data, the other pushes it forward. I call it the Miner and the Mule. The handshake happens fast enough that from the outside, it just looks like the CPAP is on the network.
Once the server ingests the data, it fires MQTT messages that get picked up by Home Assistant so my sleep therapy data flows straight into my homelab dashboard without any cloud middleware in between.
Loved what I got with two cheap ESP32 and I was able to replace a dual WiFi Rapeberry Pi doing the bridge and move the service to my main NUC.
Thinking of building a 3D enclosure to stick it in the back of the machine