esp8266-dth22-ts

Mini DIY low-powered weather sensor, ESP8266-01(ESP-01) connected with DHT22 temperature/humidity sensor, that publish data to ThingSpeak channel.

Requirement

• ESP-01 Wifi module (or any compatible ESP8266 module)
• DHT22 temperature/humidity sensor (or DHT11)
• 3.3V Power source
• Wires, connectors, etc.
• Arduino IDE with
  • Board package: “esp8266” by ESP8266 Community https://github.com/esp8266/Arduino
  • Library package: “DHT sensor library” by Adafruit (Version 1.2.3) https://github.com/adafruit/DHT-sensor-library/tree/1.2.3
• Thingspeak channel

Instruction

1. Change Thingspeak API key, Wifi SSID and password.
   • Also change the sensor type if you are not using DHT22.
2. Hardwire ESP XPD_DCDC pin (bottom right corner of the mcu) to RST pin. This is neccessary for ESP-01 to wakeup from deepsleep.
3. Upload the code to ESP using Arduino IDE.
4. Connect ESP with DHT22 and power.
   • DHT22 data pin to ESP GPIO2.
   • DHT22 Vcc pin to ESP GPIO3(RX).
   • 3.3V to ESP’s Vcc, ESP’s CH_PD.
   • (recommend) Pull-up ESP’s GPIO0,GPIO2,RST pins with 10K resistors.
   • (recommend) A 47uF capacitor between 3.3V and GND.
   • All GND to ground.

Testing and result

The sensor wakes up, reads and sends data to Thingspeak server, then goes to deepsleep for 5 minutes and repeats.

• Powered with 2x AA batteries (average alkaline, 3V.), directly connected without regulator.
  It operated for about one week until the battery voltage is dropped below working level of DHT22.