Not getting [RF12demo.12] on minimum

My boss handed me an emontx and an RFM69Pi and said to make it do something.  I have no idea if the EMONTX workes since there doesnt seem to be any led that shows power on and after plugging the radio onto a pi and following the RFM69Pi V3 wiki instructions,  I get   a stream of output lines that look like this:


? G0 166 235 31 129 102 179 137 4 224 194 136 8 184 240 1

I certainly don't get [RF12demo.12]  blah blah 

The state of the emon has no influence over the appearance of the console output, but I am not getting output without the radio so without starting to pull out a scope or signal analyzer I am assuming something is at least wiggling.   It would be nice to have a definitive way of telling that both the emontx and the radio are functional.  I was expecting an led to come on if everything ok.  I do not have emon hub on the pi and don't intend to at this point.  I just want to see the data stream from the tx.  So, how do I determine health of the parts?



Robert Wall's picture

Re: Not getting [RF12demo.12] on minimum

Look at the default sketch that is loaded into the emonTx (the emonTx Wiki tells you which and where that is).

When you read that, you'll see what outputs are sent where, and when the LED on the emonTx is turned on and what it means. You'll also find a data structure that describes the data transmitted. What you're looking at coming out of the RPi should be that as a byte stream expressed in decimal, but prefixed with the node number.
But what you report doesn't appear to have the right number of bytes, so it looks more like noise to me.

If you look at the FTDI output of the emonTx (serial, 9600 baud), that's where you see the readable text, which should start "emonTx V3.4 Discrete Sampling V2.2" or something like that. What happens after that depends on how you're powering it and what is connected.

stumpygreg's picture

Re: Not getting [RF12demo.12] on minimum

Thanks.  I will follow your lead on this and likely report back for further insights


pb66's picture

Re: Not getting [RF12demo.12] on minimum

The "G0" tells us the rfm2pi is in promiscuous mode (group 0), this can probably be altered via the serial console you are reading from, the default group of 210 can be restored by sending "210g" but there are no guarantees the emonTx is still on that group if your boss had access to a FTDI programmer.

I would at least try 210g before anything else, this is normally set by emonhub at startup.

the startup text only happens at startup and unless you can reset it while the serial console is connected you are very unlikely to see it, you should however get a help text print out returned for any un recognized command via the seial console or type "?" to see it, that should include the version number and current configuration too.

If you do not have the ftdi but do have a couple of link wires you could hook the emontx up to the serial port (gpio) of the Pi in place of the rfm2pi, search for "emonTx serial-direct" for info. 


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