Suitability of the Home Energy Monitoring system components to India

Submitted by Guest on Thu, 09/08/2012 - 08:28

Hello all,

I want to build the Home Energy Monitoring system. However, I want to be sure that it is suitable for India. I did see 915 MHz mentioned on the PCB of emonTx. Do all the components work in the 900 MHz license free band?

I would presume that the sketches would incorporate appropriate switches for enabling 240V AC operation. Is my assumption correct?

Thanks for your help.

Re: Suitability of the Home Energy Monitoring system components to India

Submitted by GaneshShivashankar (not verified) on Thu, 09/08/2012 - 12:37.

I understand that only 865-868 is license free band in India. Is it possible to get emonTx and emonBase working at that frequency?

Re: Suitability of the Home Energy Monitoring system components to India

Submitted by Robert Wall on Thu, 09/08/2012 - 14:06.

I understand only 865-867 MHz is available to you. The frequency of operation of the r.f. module is set in software, the data sheet for the RFM12B module states:

Band	Minimum Frequency	Maximum Frequency	PLL Frequency Step
433 MHz	430.2400 MHz	439.7575 MHz	2.5 kHz
868 MHz	860.4800 MHz	879.5150 MHZ	5.0 kHz
915 MHz	900.7200 MHz	929.2725 MHz	7.5 kHz

So you should be able to set the frequency within your permitted band, but you will need a deep understanding of the library code to change the command that sets the frequency.

Both the emonTx and emonBase are available through the shop with 868 MHz modules.

The voltage monitor requires a suitable adapter with an a.c. output of nominally 9 V. Again, this is available through the shop but only with a BS1363 or European plug. If you cannot get a 9 V a.c. adapter, any other low voltage will work but you may have to change one resistor in the emonTx, the fine calibration is done in the software. You should get a reasonable quality one (but not necessarily high power) because a faithful reproduction of the mains waveform is important for accurate power measurements.

(Do NOT try to use the more readily available 9 V d.c. adapter).

You also need a 5 V d.c. USB supply (or batteries for the emonTx) to provide the main operating power for both units.

[Edit] The components in the RFM12B module are tuned to suit the band, so changing frequency within the band should give much the same performance. But you cannot change to another band in software alone. It tried: an 868 MHz module will work a 433 MHz, the range is limited to about 20 centimeters with many errors!

Re: Suitability of the Home Energy Monitoring system components to India

Submitted by kishban (not verified) on Tue, 29/10/2013 - 20:01.

Hi Ganesh,

Did you manage to build a kit for use within India? Or are you aware of any such not so expensive commercial monitors available in India?

thanks

kishore

Archived Forum