OpenSprinkler Forums Hardware Questions OpenSprinkler Pi (OSPi) Is measuring 24V current possible? Re: Re: Is measuring 24V current possible?



@hf3 wrote:

Sorry, I’m a s/w, not a h/w guy…. Is there a simple circuit using one of the new ADC channels to measure the 24V current? If there were, seems that would be a good indication of whether a valve is open or shorted, which would be a nice utility to have.


Some commercial sprinkler controllers do have a feature which allows them to scan through all connected valves and detect those that are shorted. I don’t know what’s the easiest implementation, but one possible way is to use an additional resistor to form a voltage divider with the solenoid, and detect the voltage on the resistor using an ADC channel. Probably another approach is to add a current limiter circuit to limit the amount of current supplied to each channel. In any case, I am very interested in finding a simple and low-cost way to address shorted solenoids.