emonTH wireless temperature & humidity sensor with SI7021 sensor
Eagle Arduino C++
Latest commit d71f5b2 Jan 17, 2017 @glynhudson glynhudson committed on GitHub add emonth2 octopart bom


emonTH V2.0

Build Status

Low power wireless temperature and humidity node

V2.0 hardware revision adds support for SI7021 temperature and humidity. This sensor brings performance and power savings over the DHT22, see sensor folder of this repo for sensor evaluation and comparison.

The emonTH V2 is an open-source, wireless, battery powered temperature and humidity monitoring node.

Data from the emonTH is transmitted via wireless RF (433MHz) to an emonPi / emonBase web-connected base-station for logging to Emoncms for data logging, processing and graphing.

emonTH V2


  • Hardware schematic & CAD files are in the hardware folder of this repo
  • See emonTH V1 Technical Wiki for more hardware design notes.

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PlatformIO is recommended as the easiest way to compile and upload Arduino compatible firmware for emonTH. One of the big advantages of using PlatformIO is all libraries can be automatically downloaded. Arduino IDE can also be used but libraries must be manually installed.

Compile & Upload Firmware Using PlatformIO

For a full guide and installing and using PlatformIO (including visual IDE) see 'Compiling' User Guide Section. Assuming platformIO is installed

$ git clone https://github.com/openenergymonitor/emonth2
$ cd emonth2
$ pio run
$ pio -t upload


emonTH hardware is fully open-source. See hardware folder of this repo for Gerbers, Eagle CAD design, BOM & port map.