Tuya Water Leak Sensor SKU-S2502 Converted to Tasmota

uss · June 3, 2021, 6:00am

20190119_102556x

uspass/Tuya-Water-Leak-Sensor/blob/master/README.md

# Tuya Water Leak Sensor SKU-S2502 Converted to Tasmota
MCU Product ID: {"P":"SmFKLTOcGHbPQvmh","v":"1.1.0"} 
Wifi 8266ex 

![20190119_102556x](https://user-images.githubusercontent.com/42880649/120639804-6dac6180-c47a-11eb-85a8-bf8dbfecacb2.jpg)

Basically the sensor works like this:
The MCU (U3) is powered by the battery through Q2 which acts like a diode (with a low drop-off voltage) protecting it from reverse polarity.
This micro-controller takes care of:
  1. water leak tips reading p1.0
  1. battery low reading p1.2. 
  1. push button K1 reading p0.2. For WiFi pairing.
  1. Buzzer B2 writing p0.6. Sound alarm.
  1. LED D1 writing p0.7. WiFi and visual alarm.
  1. Reset ESP (EXT_RSTB) writing p1.5.
  1. ESP power writing p1.7. Power control to save battery.
  1. GPIO5 linked to p0.0.
  
In order to save power, ESP (U1) is powered through Q3 which is normally closed (VM0=0).

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Cheers,
us

bluk · January 10, 2022, 5:07pm

Thanks! Any idea why the battery would overheat within 10 seconds of being inserted?
Everything works well and reads properly when powered by serial but with the battery I get instant heat. Using a Merkury if that makes any difference? Cheers

uss · January 10, 2022, 9:50pm

Looks like a short circuit. See the diagram and try to localize it.