Low cost Wifi Humidity sensor with ESP8266-7 or ESP8266-12 Wifi module and SHT21 digital humidity and temperature sensor. The board has on-board 3.3V regulator and can be powered from USB charger with USB-A socket. Deep sleep function is supported for entering ultra low power mode. There are also an on-board status LED and a PROG button for entering the program mode (hold down while power-up). Programming header is standard FTDI style UART serial interface. Humidity sensor is located away from other components and separated with cut out slot for better thermal isolation. The board dimensions are designed to fit the off-the-shelf enclosure.

Features:

• Wifi module: ESP8266-7 or ESP8266-12
• Digital humidity and temperature sensor: SHT21 or HTU21D
• Supply voltage: 5V
• FTDI 0.1″ locking header for programming and debugging
• UART logic level: 3.3V
• Program button
• Status LED
• Deep sleep function: supported
• Pins
  • LED: 13
  • SDA: 2
  • SCL: 14
• Optional enclosure: Multicomp 1603603

Resources

• Design files on github
• EmonCMS
• Arduino sketch for sending TaaraESP SHT21 data to EmonCMS
• Arduino sketch for sending TaaraESP SHT21 data to MQTT broker
• Arduino IDE support for ESP8266
• HTU21D Library from SparkFun

Buy

• Bare PCB: 3€