A low power wireless energy monitoring node designed to sense data from multiple CT current sensors, optically from a pulse-output utility meter and from multiple one-wire temperature sensors. It can be powered by 2 x AA batteries or 5V USB.

Technical
ATmega 328 with Arduino Uno bootloader
3 x CT sensor inputs
1 x 3.5mm jack DS18B20 input
1 x 3.5mm jack pulse-counter sensor input
1 x 9V AC-AC adapter input
On-board HopeRF RFM12B wireless transceiver module - 433 Mhz - worldwide ISM frequency band
3.3V board voltage
Power supply: 5V mini-USB / 2 x AA batteries

Note: Soldering assembly is required and an FTDI cable is required for programming

Kit Includes
emonTx PCB + all necessary components

Does not include
FTDI programming cable
Clip on CT current sensor, temperature, optical or AC-AC (voltage adapter) sensors
CT sensors give a much better reading of instantaneous power than pulse counting, we recommend using a CT whenever possible. When monitoring power using pulse counting method from a utility meter the sample rate is limited to the number of pulses, at low power values the pulse rate can be extremely slow.

Documentation
emonTx documentation & step-by-step build guide: http://openenergymonitor.org/emon/emontx
open-source hardware design: http://solderpad.com/openenergymon/emontx/
GitHub Arduino firmware examples: https://github.com/openenergymonitor/emonTxFirmware