If you have been following the blog and twitter over the past couple of weeks you will probably have noticed that we've been gearing up for and starting manufacture (part 1
and part 2
) of a trio of new hardware units:
1. emonTx V3
The emonTx V3 is our new flagship energy monitoring wireless node
. Thanks to community contributions and user feedback we've improved on the previous through-hole emonTx design while trying to keep as much flexibility and user customisation potential as possible.
|Full emonTx V3 system with 4 x CT-sensors an AC-AC power adapter: Real Power, Power Factor and VRMS measurements|
The unit uses the same Atmel ATmega328 Arduino compatible microprocessor and all free I/O pins have been made accessible on a screw-terminal block for easy expandability.
Apart from the obvious change in enclosure and move to SMT pre-assembled electronics, the most notable hardware improvement is the addition of an AC-DC circuit. This enables the emonTx V3 to be powered from a single AC-AC plug-in adapter while simultaneously providing an AC voltage sample for VRMS and Real Power measurements.
|emonTx V3 with ATmega328, RFM12B and on-board 3 x AA batteries|
Instead of having a separate firmware sketch example for each function as we had with the emonTx V2 (e.g. Real Power (CT123_voltage), Apparent Power (CT123), Temperature etc.) we have for the emonTx V3 made progress combining all these into one 'auto-adaptable' piece of firmware. We have called it emonTxV3_discrete_sampling, it's based on EmonLib but no longer relies on the internal bandgap of the Atmel chip for ADC measurements. This will increase ADC accuracy and reduce the need for additional calibration. The main features of the firmware at present are:
- CT detection – only sampling from required channels
- Power supply detection & presence of AC-AC adapter – VRMS and Real Power measurements are enabled if powering from AC-AC adapter and power saving mode is enabled of powering from batteries
- Temperature sensor detection – external DS18B20 temperature sensors are auto detected and temperature readings added to measurements
The name 'discrete sampling' was used to draw distinction between the EmonLib based discrete sampling approach and Continuous Sampling. A Continuous Sampling PLL example is included in the emonTx V3 examples, after some testing we hope to integrate this into the main firmware: the emonTx V3 could switch to a more accurate continuous sampling mode when powered from AC-AC adapter of 5V DC USB. The emonTx V3 is now available from the OpenEnergyMonitor shop.
2. emonTH Wireless Temperature and Humidity Node
|emonTH Temperature and Humidity Node|
The emonTH is a new unit to replace the Low Power emonTx Temperature node (which was bit of a cludge!).
|emonTH installed in my house, I will be keeping a close eye on temperature and humidity in my house over the winter in North Wales|
Working with community groups like the Manchester Carbon Coop
who are involved in retro-fitting houses with insulation we realised the need for an easy to deploy, long lasting temperature and humidity monitoring node. Many emonTHs can be deployed thought a house or building to inform a building performance model
, heating control system or just for general interest! The emonTH supports DHT22 and DS18B20 sensors as well as simultaneous indoor and outdoor temperature readings using a remote DS18B20 sensor
wired into terminal block.
As with the emonTx the data is logged via a web-connected base station to emoncms server for logging, graphing and analysis. As with all our hardware, the emonTH is open-source and Arduino IDE compatible using the ATmega328 with the Arduino serial bootloader.
The emonTH is now available from the OpenEnergyMonitor shop.
|The emonTH comes pre assembled and has an on board DC-DC converter to increase battery life.|
3. emonTx Arduino Shield SMTArduino compatible energy monitor shield add-on.
|emonTx Shied SMT on Arduino Leonardo|
For prototyping and lab experiences an Arduino is a great tool to quickly try something. The emonTx Shield allows energy monitoring functions to be added to a standard Arduino Uno / Leonardo or Yun as well as a Nanode RF
. As with all our hardware units we provide as many software examples to help you get up and running. The emonTx Shield SMT uses Surface Mount (SMT) pre-assembled electronics. To keep costs down the through-hole components (headers and connectors) require manual solder assembly.The emonTx Shield SMT is now available from the OpenEnergyMonitor shop.