I am working on a Project that require something very simple. Is actually so simple that I’m more worried about getting it the most efficient way (less price with better solution).

The project require a signal to turn ON a 24DCV solenoid valve for approximately 3 seconds and then shut it OFF for 15 seconds and then repeat indefinitely until the user shut the system down. I was also thinking on making this time 1 and time 2 adjustable with a potentiometer.

The first solution came to my mind was to use a LM555 but I’m not sure if I can get that big times in-between oscillations and also that difference between ON and OFF.

Another solution I thought about (and I’m sure will work) is to use an Arduino UNO to send the signal to a relay. Then I start to think in the cost of an additional power source for the Arduino (5 to 12 VCD I think) and also remembered that the LM555 doesn’t use 24VCD either.

I’m only a beginner in this electronic stuff but I’m also sure that there is some kind of a timer that does what a need, the problem is that I don’t know where to start looking for.

Thanks for your help and taking the time to read all this.

  • \$\begingroup\$ Solenoids get driven by a relay. Relay is connected to a 24 V supply. A transistor switch or other buffer is used to control relay from an electronic source of some kind. Bufferinput can be from whatever you like e.g. push button, 555, or microcontroller. This buffer stage is what lets you mix low voltage sources with 24V relay. The easiest way today is probably an arduino. There are relay drive shields available \$\endgroup\$
    – crasic
    Jul 22, 2015 at 4:38

1 Answer 1


I think for whatever control circuitry you end up using, you are more than likely going to need a second lower voltage (step down the 24VDC to 3.3-5VDC). So, if this was my project, I'd probably use a simple microcontroller. An Arduino board would work. This would be the easiest way to control the valve using timers and potentially having a pot to select different time delays. You could even throw in an LED for when the valve is on/off.

I just did a quick search and came across this: http://www.instructables.com/id/Controlling-solenoids-with-arduino/ Not sure how well it is designed but it could be a starting point for you.


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