Shelly Plus Plug UK - teardown and pin outs

ESPHome
1

I couldn’t find any information on running the Shelly Plug Plus UK under ESPHome, but I bought a couple guessing that they’d be the same inside as the EU version. Turns out that’s not quite true. I quickly semi-bricked mine by OTA flashing it to ESPHome, not realising that the new locked bootloader means that you can’t then OTA flash it again, so that gave me enough of an excuse to take it apart.

image
image881×919 37.2 KB

The front plate is glued on, and can be removed by sliding a blade between the LED ring and the body, and carefully working it all the way round the outside.

image
image1225×919 149 KB

There are three PCBs. The top is the LED board, this just pulls off.

image
image1225×919 141 KB

The main PCB is soldered to the live and neutral pins on the back. The ESP32 board is mounted sideways next to the left of the earth pin. The riser pins for the LED board rule out any chance of accessing the ESP32 board without removing the main board (both are soldered from the underside of the main PCB).

The ESP32 board has test points for serial. I soldered wires to these to serial flash it.

image
image689×919 85.7 KB

Brown = GND
Red = 3.3V
Orange = GPIO0
Yellow = RX
Green = TX

The unsoldered pad to the right of the red is CHIP_PU.

I traced the pin outs while I had it open:

Switch = GPIO4
Relay = GPIO32

The LED ring is a set of normal RGB LEDs:

Red = GPIO12
Green = GPIO26
Blue = GPIO14

The temperature sensor is a 10k NTC next to the big 1mΩ resistor in the bottom left, connected to GPIO34.

The power sensor is a BL0937, with:

SEL = GPIO27
CF1 = GPIO25
CF = GPIO33

(I’ve not tested these three yet)

Hopefully this is useful to others. I’ve got another one that I’m going to attempt to flash to ESPHome OTA using the code on PR5535.

7 Likes
2

Thank-you so much!! I’ve been looking high and low for these pin-outs !!!

3

Great Work! Can I ask how you removed the main Relay board so you could access the ESP sub board? Is it a matter of removing as much solder as possible from the 2x rectangular pins below the power connectors … then easing the board out? I managed to brick my new unit … also quite easily🙄 I would like to flash with Tasmota.
Thanks and Best Regards Norman

4

Probably a bit late, but the “with difficulty” is the answer. You’ve got to be careful with the heat as the pins are housed in plastic.

Adding leaded solder will help - I added leaded, removed as much as possible, and then added more leaded, then I think I “walked” it up the pins by melting one side and pushing sideways on the other contact to lift that side a little, then repeat alternating sides.

I mostly popped back to say that I just bought a 3rd one of these and finally succeeded in converting it to esphome OTA, by following the instructions here and then here.

When you do the Tasmota autoconfiguration step, there’s no Shelly Plus Plug UK, but it worked using the Shelly Plus S option. I’ve no idea if this gives a working Tasmota configuration, but it’s enough to do the safeboot conversion for converting to esphome.