Circuit design - DPST relay to 1 and 2 pulses?

Thread Starter

alexgoresin

Joined Oct 12, 2017
1
Hi, I'm new to the forum so hope this is the right place to post this question.

We've just installed solar panels on our house and when the sun shines, it generates plenty of power to run the pool pump (controlled by a timer). When the sun does not shine, the pump still runs, however it uses power from the grid, which becomes very expensive. I would like to be able to switch the pump off when the sun is not shining, however the pump controller is 'old skool' and can only be controlled manually via a press button (which cycles it between Auto/ON/OFF).

I have (bought for another project which did not proceed) a Lorentz Solar Intensity Sensor, which has a simple relay output. The challenge is to have the Lorentz turn the pump to 'OFF' when there is not enough sun, and 'Auto' when there is. The ideal solution would convert the relay input to a pulse output (of say half a second duration) so that when the relay closes (sun shining), one pulse is sent (OFF->Auto), and when the relay opens (not enough sun), 2 pulses are sent (Auto -> ON -> OFF). Is this something that can be achieved by say using 555 timers? Can someone design a simple circuit for this?
I'm good at soldering and have some electronics knowledge but am not any good at circuit design so hope someone on the forum can help.

Appreciate any feedback or assistance, particularly if there is an off-the-shelf solution available.

Alex
 
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