Simple Reverse Current Detection

I've never messed with the Arduino etc. and don't really have much spare time to play with this, so I'm looking to do this with fully built kit that I can just buy, and maybe perform some small software mods etc.

What I'm looking to do is simple - I already monitor energy usage using a Current Cost Envir and a clamp... however I've recently had 6kWp of PV installed and of course the clamp can't tell what direction the current is flowing in. I've got one of the Landis and Gyr E110 variants, which has an LED pulse which stays on when reverse current is detected. So, all I want to do is get something that can tell me as soon as the LED is on for longer than a typical pulse, and use this as a "direction" signal for my existing monitoring.

That would be simple enough, but the main issue is that my meter cupboard is outside, so it would be a pain to have to run wires to it etc. My thought was to use a pre-built emonTX and a receiver for my existing PI, and mod the firmware on the emonTX so that as soon as it detects a solid LED, it sends a signal to the Pi. My ( very limited ) look around this site though suggests that the pulse sensor in the emonTX triggers an interrupt on the trailing edge of the pulse, so unless there's also a way to poll the current led state ( efficiently ) then this might not work. Does anyone have any pointers for me?


calypso_rae's picture

Re: Simple Reverse Current Detection

Hi Adam, and welcome on board.

I have always detected changes of state in a meter's LED by polling rather than using an interrupt.  I have plenty of hardware oddments here which should be able to do as you are asking for.  You may also want to do some additional monitoring & control of any surplus power.

To discuss these options, just send me a PM.


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