This is an ESP32 to RS232 adapter for the Monoprice 6ch Whole Home Audio Amplifier.
It has support for both a serial-socket interface (to support the existing iOS apps / HomeAssisstant integration) as well as direct control via ESPHome (via web-server ui, or via HomeAssistant API/Mqtt).
I currently have it configured to also have a relay and a 12V trigger onboard, to control the PA functionality. However, this could just be done via software as well.
I made an initial run of 5 PCBs via JLCPCB (total cost: $22 shipped), with all of the non-modules listed below presoldered. It works excellently electrically. Physically, I needed to expand the cutout for the ethernet port, and add a small cutout for the RS232 (done).
You can find my schematic here
Additional changes that would make it better:
- Place 3.5MM next to WT32 port, so that it comes out in parallel to the ethernet cable.
- Arrange the USB boost converter so that the cable can come out besides the null modem adapter.
- Relayout around making a custom 3d printed enclosure. I was trying to fit in 100x60x25mm Project Box, but I think that even if I had the cutouts properly, it'd still be ~2mm too tall. Right now, it wont take the lid.
Additionally, ESPHome has a bug currently where the WebUI for ESPHome won't show the values for all the sensors, if you have a boatload of them. Not a problem if you just use the HA integration.
If you'd like a PCB + the breakouts I've listed below, please reach out! I will distribute at cost.
You need a null-model (crossed pins) Male-Male cord to connect. Amazingly, these are hard to find. The combination below yields cables for ~$6 each
- ESP: https://smile.amazon.com/gp/product/B099PDG16B
- Power (provides 5V for ESP, and 12V boosted for trigger): https://smile.amazon.com/gp/product/B08R5LMQH1
- Serial breakout:
https://smile.amazon.com/gp/product/B07Z5Y1WKX(The exact item I ordered is no longer available, but it looks like this: https://smile.amazon.com/gp/product/B07PFB4MHR ) - Serial cable (straight through, M-F): https://smile.amazon.com/gp/product/B081GHYHPR
- Serial null-modem adapter (M-M): https://smile.amazon.com/gp/product/B01HMNIYJQ
