I am trying to make a rudimentary energy metering system for my workplace. We have several Countis E50 meters in place which feature a pulse output. The output is 100VDC at 0.5A.
What I would like to do is detect these pulses with a Pico W and transmit them to a server. The Pico requires 3.3V on the GPIO pins for the detection.
How can I lower the 100VDC down to the 3.3V for the Pico to detect, and maintain safety? I believe a resistor network / voltage divider may work but I feel like optoisolation might be a better option.
EDIT: The pulses are 100ms in length and happen every 10 WattHours of usage. So the time that the voltage is on will vary by usage of the downstream circuits.