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Topic: Boat bilge pump on detection 22-27VDC (Read 101 times) previous topic - next topic



I need to make a bilge pump sensor to know when the pump is on and off and detect duty cycle incase it comes on more frequently than normal for example.

The pump is connected to a float switch and also to an on/off/automatic switch (automatic meaning the float switch controls if the pump comes on or not)

The 24vdc is nominal and is connected to batteries and a DC alternator, so the voltage can change from about 22v to about 27v.

I am trying to find the best way to detect if the pump is active and for how long.

I am considering optocoupler on the 24v side and then connect it to the arduino pin on the low voltage side. If the float switch goes on, then the pump gets nominal 24v and this will activate the optocoupler and send a voltage to the arduino which I can then detect, but I am not sure if optocouplers work this way.

Another option I am considering is a relay, that turns on and closes the pin on the arduino.

Also, I am considering a float switch directly to the arduino to use as a validation, if the float switch is on and the bilge pump is on, but the float switch does not go off after a few seconds, then the pump has failed and an alarm can go off.

Please could you help or give me some advice, I am fairly new to this and I don't know, what I don't know, if that makes sense?

thanks in advance


An opto-coupler is a good idea if you are interfacing 24volt electronics to an Arduino. Your ~24 volt circuit drives the LED of the opto-coupler through a series resistor (say 4.7k).

start here, for example https://electronics.stackexchange.com/questions/36517/opto-isolated-arduino-input

You can set an alarm in your sketch if the pump has been active for more than tolerable period.

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