I have a dehumidifier that I’m trying to make ‘smart’ with an ESP32 board.
• I can control the control buttons by bridging them with a relay controlled by the ESP.
• I’m trying to read the ‘state’ of the dehumidifier by taking the power signal from multiple LEDs on the dehumidifier panel and feed that into the ESP via the ADC GPIOs.
The LEDs are multiplexed by the IC on the PCB so this is making ti difficult for me to find a HIGH signal to trigger the ESP.
Issue: The power coming from the (+) of the LEDs seems to be fluctuate very erratically (from 0.3v to 2.20v) regardless if the LED is lit/on or not.
(voltages jump around when measuring with ESP or multimeter).
I currently have the ESP monitoring x3 LED’s on the dehumidifier and it is impossible to tell what one of the three is on and what ones are off due to the voltage bouncing around so much.
The (-) side of the LED’s share a common trace in the PCB so can not measure off that side.
I’m at a loss of how to achieve this and hopeful that you lot are much smarter than me here 
.
Additional info:
ESP is powered via a 5v circuit inside the dehumidifier.
ESP Config I’m using for testing:
captive_portal:
binary_sensor:
- platform: template
name: "TEST Probe32 Triggered"
id: mb_b
lambda: |-
if (id(test_pin32_probe).state > id(test_probe32_trigger_level).state) {
return true;
} else {
return false;
}
- platform: template
name: "TEST Probe33 Triggered"
id: mb_c
lambda: |-
if (id(test_pin33_probe).state > id(test_probe33_trigger_level).state) {
return true;
} else {
return false;
}
- platform: template
name: "TEST Probe34 Triggered"
id: mb_a
lambda: |-
if (id(test_pin34_probe).state > id(test_probe34_trigger_level).state) {
return true;
} else {
return false;
}
sensor:
- platform: adc
pin: GPIO32
attenuation: auto
name: "TEST Pin32 Probe"
id: "test_pin32_probe"
icon: mdi:lightning-bolt
update_interval: 0.1s
filters:
- sliding_window_moving_average:
window_size: 30
send_every: 5
- platform: homeassistant
name: "TEST Probe32 Trigger Level"
id: "test_probe32_trigger_level"
entity_id: input_number.test_probe32_trigger_level
- platform: adc
pin: GPIO33
attenuation: auto
name: "TEST Pin33 Probe"
id: "test_pin33_probe"
icon: mdi:lightning-bolt
update_interval: 0.1s
filters:
- sliding_window_moving_average:
window_size: 30
send_every: 5
- platform: homeassistant
name: "TEST Probe33 Trigger Level"
id: "test_probe33_trigger_level"
entity_id: input_number.test_probe33_trigger_level
- platform: adc
pin: GPIO34
attenuation: auto
name: "TEST Pin34 Probe"
id: "test_pin34_probe"
icon: mdi:lightning-bolt
update_interval: 0.1s
filters:
- sliding_window_moving_average:
window_size: 30
send_every: 5
- platform: homeassistant
name: "TEST Probe34 Trigger Level"
id: "test_probe34_trigger_level"
entity_id: input_number.test_probe34_trigger_level
Photo of the control PCB:
