I recently brought some Fcmila RGBW bulbs and I discovered that they switched to a new app (“Cloud Intelligence”) and they cannot be flashed with tuya-convert.
I opened a bulb and found a new daughter board, based on the OPL1000 chip:
I’m trying to replace it with an ESP-12 board to make it work with Tasmota and HA.
I checked with an oscilloscope the pins when controlling the board with the official APP… on RGB pins I was able to find the expected PWM signal (4KHz) that changes its duty cycle depending on the brightness and color I choose.
What I cannot understand is the “C” and “W” pins… I thought W was for the white leds, but it stays flat (referred to GND), while the “real” white PWM outputs from pin C.
I connected an ESP-12 module to pins GND and 3.3V and it works… but when I try to connect a pin (for example D4) to the main board the blue led of the module stays ON and I cannot connect to the esp chip…
the problem occurs only if I connect the top board (the one with LEDs).
If I connect, for example, PWM1 to RED pin, when I power it on the RED leds are on at the max brightness and the esp board doesn’t boot (blue led fixed)
my bulb has only cold white so it should be ok that W signal is always GND…
I still have to figure out why, if I connect the LED board, the ESP12 is stuck.
In addition I reverse engineered the LED board… it has 3 MOSFET for RGB but only one “power” pin for white leds…:
I chose Tasmota simply because it’s the firmware I’m using for all my smart devices… but as soon as you modify the lamp, you can upload the firmware you prefer.
