I’ve tried the DHT11 sensor modules at both Vcc 3.3V and 5.0V, and at both voltages the humidity values are bad. dfrobot has introduced a V2 DHT11 sensor module that changes the 10K pull-up to 4.7K.

We’ve said it before but it’s worth repeating: rolling your own hardware solution is ridiculously easy these days. If you want to make a network attached environmental sensor, you wire a DHT11 ...