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emonTH Temperature & Humidity Node

  • Wireless temperature & humidity monitoring node
  • Communicates with emonPi & emonBase via RF (433Mhz)
  • 1yr+ battery life (2 x AA not included)
  • Up to 4x emonTH can communicate to a single emonPi*
  • Internal temperature & humidity + optional external probe
  • Optional pulse sensor input

* More than 4x emonTH units can be connected to a single emonPi / emonBase with manual change of RF nodeID. This can be done via serial node ID config


emonTH Setup

1. DIP Switch Config (emonTH V1.5 and up)

If more than one emonTH is to be used with the same base-station, each emonTH will need a different RF node ID. The node IDs on each unit can be set using the on-board DIP switch; this enables four node IDs to be selected by changing the switch positions without the need to change the firmware (as before). Up to 30 emonTHs can theoretically connect to a single emonBase / emonPi.

A USB to UART cable and Arduino IDE can be used to set additional unique node IDs by changing the nodeID variable at the beginning of the sketch.

Alternatively, we are happy to set the node ID for you before shipping (please leave us a note with your order).

DIP 1 DIP 2 RF node ID V1.x firmware RF node ID V2.x firmware
OFF OFF 19 (default) 23 (default)
ON OFF 20 24
OFF ON 21 25
ON ON 22 26

2. Install Additional Sensors

An internal temperature and humidity sensor is built in to the emonTH, additional external sensors can be connected if required:

Only one external DS18B20 sensor can be connected to an emonTH with standard firmare. If more than one DS18B20 is required see emonTH alternative firmware.

3. Power Up

  • Power emonTH from 2 x AA batteries
  • Alternatively 5V DC can be wired into terminal block if required

4. Indicator LED

  • Illuminates solid (dimly) for a few seconds at first power up
  • LED should then extinguish to indicate successful sensor detection
  • Flashing LED indicates sensor detection failure
  • To preserve battery LED does NOT flash regularly during operation

5. Emoncms Setup

  • RF transmission from the emonTH will be picked up automatically and data will appear in local Emoncms Inputs page.
  • If Remote logging has been setup, data will also be posted to Emoncms.org.
  • See guide Log Locally for an overview of logging inputs to feeds. For EmonTH inputs select a feed interval 60s or greater:

Important: the emonTH reports data at a 60s interval, it's important to log the data to emoncms with a 60s inerval as shown below:

emonth input process

Note: If using more than 4x emonTH units (with custom RF node ID or modified firmware) emonhub.conf node decoders will need to be setup.