Adding Extra Inputs to Tuya Zigbee Switch – Flashing & HA Visibility

Hardware
1

Has anyone ever modified or flashed a Zigbee (Tuya) switch to add an extra input, and made it visible in Home Assistant?

I’m looking to connect a PIR sensor input directly to the switch I/O. That would save me from using a separate device, especially since the switch already has the right voltage levels and some spare I/Os available.

I’m not sure if the additional inputs might already be readable by the chip-config, but just not exposed in the HA template. Is there a way to debug or inspect what the device is actually reporting, maybe via Zigbee2MQTT or ZHA logs?



Also, I’ve noticed quite a difference between two very similar Tuya Zigbee 3.0 switches:

  • BL702C10 (also BSD17)
    • Manufacturer: eWeLink
    • Model: SWITCH-ZR03-1
    • Side button
    • Antenna placed on the outer side
  • ZT2S
    • Manufacturer: _TZ3000_skueekg3
    • Model: TS0001
    • Rear button
    • Antenna placed on the relay side

The BL702C10 has much better reception. The ZT2S struggles, even after I soldered on an external WiFi antenna (following several online guides).

BL702C10 BSD17
BL702C10 BSD171280×1000 103 KB
BL702C10 BSD17
BL702C10 BSD171280×1271 156 KB
BL702C10 BSD17
BL702C10 BSD17901×1280 98.2 KB


ZT2S
ZT2S960×1280 164 KB
ZT2S
ZT2S985×1280 195 KB
ZT2S
ZT2S1280×1214 165 KB

2

Not sure if this will be of help, link below. There is a pretty good set of open sourcing work on Bouffalo Lab chips, check GitHub for BL702 related projects. Make sure to do any low voltage work with the device disconnected from mains :skull_and_crossbones: .Good hunting!