EmonTx Arduino Shield

emonTx Arduino Shield

An open-hardware wireless energy monitoring Arduino compatible (Duemilanove,Uno and Leonardo) shield.

See non-invasive section of building blocks for theory behind CT energy monitoring.

Overview

• Apparent Power, Real Power*, Power Factor* and AC RMS voltage readings*
• 4 x CT Current Sensor input
• AC 9V RMS voltage sensor input
• 433/868Mhz RFM12B (HopeRF) wireless transceiver to transmit/receive data to other OpenEnergyMonitor and JeeNode modules
• On-board DS18B20 digital temperature sensor (not included as standard)
• Status LED
• Compatible with Duemilanove,Uno and Leonardo
• Compatible with OpenEnergyMonitor modules (emonGLCD, emonBase - NannodeRF etc.)

* with 9V AC adapter

Design Files & Part List

• 10 x 470K (yellow, violet, yellow, gold)
• 5 x 10uF
• 4 x 33R 1% (orange, orange, black, gold, brown)
• 4 x 10K 1% (brown, black, black, red, brown)
• 4 x 4K7 (yellow, violet, red, yellow, gold)
• 4 x 3.5mm jack (Rapid: 20-0157)
• 1 x 0.1uF (100nF)
• 1 x 470R (yellow, violet, brown, gold)
• 1 x 100K 1% (brown, black, black yellow, brown)
• 1 x 2.1mm DC barrel
• 1 x RFM12B 868/433Mhz (HopeRf)
• 1 x 82mm/165mm Ant
• 1 x 3mm LED
• 1 x DS18B20 temperature sensor (optional - not included as standard)
• 1 x 6 pin ISP header (female)
• 2 x 6 pin header*
• 2 x 8 pin header*

* or 1 x 28 pin header

See OpenEnergyMonitor Shop for recommended CT and recommended plug-in AC-AC adapter

See building blocks for more information on CT's and AC-AC adapters.

The emonTx Shield schematic and board design in Eagle CAD format can be viewed and downloaded from the emonTx Shield SolderPad Git Repo

Build Guide

(In the making) WAITING FOR PHOTOS

Hardware Setup Instructions

On the top of the board there are two solder jumpers which need to be connected before emonTx Shield can operate. To make connection the middle solder pad should be connected with a blob of solder to either the left of right solder pad, depending on the connection required. The solder can be re-melted and adjusted at a later date if required.

RFM12B Slave Select (SS) - The left hand solder jumper determines which Arduino digital I/O is used for the RFM12B SS pin. In order to use the JeeLib library out of the box this should be connected to 10 as shown in the image above. However if Digital 10 is required by another shield Digital 9 can be used by connecting the solder jumper up the other way and adding the line rf12_set_cs(9) is added before rf12_initialize in void setup().

RFM12B Interrupt - The right hand solder jumper sets the RFM12B interrupt pin. The setting of this jumper depends on which Arduino board the shield is connected. This must be set to Digital 2 for Arduino Uno/duemilanove or Digital 3 for Arduino Leonardo.

For more information on RFM12B connection to Arduino see this this building block section

Port Map

Function	Arduino Port
9V AC sample	ADC0
CT 1-4	ADC 1-4
DS18B20 Temperature	Dig4
LED	Dig9
RFM12B SS	Dig10 (recommended) / Dig5
RFM12B INT	Dig3 Leonardo / Dig2 Uno

Example Arduino Sketches

See emonTx Shield Folder in emonTx Firmware examples GitHub Repo

Follow instructions on the GitHub readme for required Arduino libraries