SMTONOFF 63A Power Monitoring DIN Relay (SMT002)

Available from:

Install method:
USB to Serial

GPIO #Component
GPIO00 Button 1
GPIO01 None
GPIO02 None
GPIO03 CSE7766 Rx
GPIO04 None
GPIO05 None
GPIO09 None
GPIO10 None
GPIO12 Relay 1
GPIO13 LedLink
GPIO14 None
GPIO15 None
GPIO16 None
GPIO17 None
For more accurate energy consumption measurements this device requires power monitoring calibration.


  1. you must remove the 4 rivets holding the 2 sides together
  2. remove the 2 cable connectors from the PCB, remove the button and 2 light guides, then lift and flip the pcb
  3. on the backside locate the ESP 8285 and using the pinout below solder 4 wires to 3.3V, GND, TX and RX. Tip: use GND form the power button, easier to access

:warning: the pins are VERY small, it’s a difficult job as 3.3V, TX, RX are next to each other