Originally posted by venquessa
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I have added a 1.5M resistor to the ADC pin of the wemos D1 mini A0. This is in addition to the internal voltage divider on that particular pin. This will allow me to monitor the voltage of the particular source. If the primary source falls below a threshold, I will have the wemos turn the SSR off and turn on the secondary source. I discussed the anti parallel issue on an electronics forum. Without using expensive mosfets, I was advised to use Schottky diodes to prevent the two sources from becoming parallel if a fault occurs and both SSR's are allowing current to flow. I will obviously have voltage drop through the diodes, but it will hopefully be minimal. I still need a short circuit protection device. I am looking at the simple crowbar configuration for that.
Here are a couple of images (top and bottom) of the PCB. I have circled how I handled the surface mount grounding issue. I simply made a small trace on the top of the board to get away from the pad and then a via to the ground plane. I am not sure if this is the best way to handle this, but it is what I did.
Thanks!
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