Simple test is to use another GPIO pin for connecting the DHT sensor. If it works, then the previous GPIO is bad.Is there a way to check if a GPIO pin is undamaged ?
You can also use a raspberry pico (lower cost than a RPi) with your DHT11 and check if it works (exclude possibility of a bad sensor). The oscilloscope trace for a DHT sensor attached above was taken with a pico running micropython. I happened to have a breadboard with a pico and a DHT22 sensor lying around here.
A complete test is more complicated. Output behavior is to place almost zero volt or almost 3.3V with a load of prox 8mA. Try different load currents and run experiments with output drive strength. Check if GPIO input is reading low or high. Use a high series resistor of say 100k for input tests too, showing whether there are low (error) bypass short in the GPIO. Checking internal pullup, pulldown resistors should be done: add internal pullup/pulldown to the input and measure current (or voltage with a 10k resistor to GND, VCC3.3V). Some fun for a rainy sunday afternoon.
Statistics: Posted by ghp — Fri Feb 20, 2026 9:50 pm