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Topic: Adapting eHZ IR receiver schematics for Arduino? (Read 1 time) previous topic - next topic

vwegert

Hello,

I'd like to use an Arduino board to capture data from smart meters - devices like these:

They have an IR transmitter that sends a SML package about every 2 seconds. From what I've read so far, the transmission uses standard serial protocols (9600 baud, 8N1 or 7E1), so I should be able to use the onboard UART, right?
I've found some schematics for an IR interface at http://wiki.volkszaehler.org/hardware/controllers/ir-schreib-lesekopf#stromlaufplan (I need only the first part, the second part is the IR transmitter). Some of the components that are used there are not that easy to get for me, and I wonder whether I really need all this or if there's a simpler way to get this done. Does anyone have expericene in this area?

Thanks
  Volker

el_supremo

I thought smart meters used a wireless protocol, not IR. Have you got a spec of what it sends?

Pete

vwegert

Pete: I'm unsure about the difference between IR and wireless protocol - I'm more the software guy. With "IR", I only meant the frequency of the light - infrared instead of visible light. Some general notes can be found at http://en.wikipedia.org/wiki/IEC_62056. As far as I understand the matter so far, this is just a standard asynchronous serial transmission like RS-232, but using infrared light instead of a direct electrical connection.

el_supremo

Quote
I'm unsure about the difference between IR and wireless protocol - I'm more the software guy

You really are stretching my credibility to the breaking point. What kind of software guy doesn't know the difference between IR and wireless/wifi/etc.?

But, *if* the meter follows the specification you linked to, that communication protocol requires that the meter reader press a reading device against the faceplate and the reader device must then identify itself before data is transmitted. So, in that case unless you know how to transmit the identifying code you aren't going to get any response from the meter.

Pete

vwegert

Pete: This might not be a problem of credibility, but of technical jargon. Maybe we're thinking along the same lines, but I'm not able to provide the information you need because I don't understand the contradiction in "smart meters used a wireless protocol, not IR".

As for the identification, that's only necessary to change the configuration of the meter. Left to itself, the meter will send a SML message every two seconds, whether there's someone there to listen or not. One application is described here: http://kuehnast.com/s9y/archives/460-Stromzaehler-auslesen.html (german, sorry). I want to do something similar - intercept the contents of the message and store it for later processing.

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