Hello @sbollaerts there is only one analog input available on the M5Atom Matrix: GPIO34 which is shared with GPIO23. Please check out M5AtomMatrix Schematic In order to use the analog input you'll need to set GPIO34 as input and disable pullup/pulldown resistors of GPIO23. Below code works for me: #include <M5Atom.h> void setup() { M5.begin(true, false, true); pinMode(GPIO_NUM_34, INPUT); gpio_pulldown_dis(GPIO_NUM_23); gpio_pullup_dis(GPIO_NUM_23); } void loop() { Serial.printf("GPIO34: %d\n", analogRead(GPIO_NUM_34)); delay(1000); } Update: I just realised that GPIO33 can also be used as analog input. pinMode(GPIO_NUM_33, INPUT); Serial.printf("GPIO33: %d\n", analogRead(GPIO_NUM_33)); Cheers Felix