DIY: Cheap wifi-based temperature/humidity sensor based on ESP8266 & DHT22

[1technophile]

@DaveL

I have a few NodeMCU ESP-12P development boards and AM2302 (DHT22) sensors and the goal is to get them inputting via my Mosquitto MQTT. An added handicap is that I’ve done very little with Arduino and don’t quite get many of those programming commands yet.
I found a very simple program to load into the board and via serial monitor can get it to show output values. But when I get to the point of configuring values to feed to openhab via MQTT…it’s gets very fuzzy for me. Does someone have a good workable example I can use to learn? The code examples above are old and I’m having trouble getting them to work at all.

Another solution available recently is an LYWSD03MMC + an ESP32, no soldering required, you will have a cheap, durable, low power solution to get temperature and humidity.
More info below:

XIAOMI Mijia Bluetooth Thermometer 2 integration

Another solution below : [4$ Xiaomi thermometer custom firmware LYWSD03MMC BLE TLSR8251] With this custom LYWSD03MMC firmware (supported by OpenMQTTGateway), the LYWSD03MMC advertises its data without encryption, so no need to connect to the sensor when using it. The data are read every BLEinterval, 55s per default, like all the other devices that advertise data. Note that the device flashing process takes less than 5minutes and is done over the air (impressive :-)).