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Timer gadget to press a button (on a dishwasher)? Answered

Back in the days when appliances had real dials and switches on them, you could set the program and then put it on a timer switch so that it would run on off-peak electric. Now that they're all software controlled with soft switches you can't do that unless you either pay a premium for one with a timer or if they have memory to resume the program from a power cut.

What I'm looking for is a simple little thing with a timer on it that you stick over the top of the soft power button, and it will press it (unless you can trigger a soft switch like a capacitive switch by sticking a voltage in front of it?) when the timer runs down.
Is there a little gadget to do this? or does anyone have plans to build something?
I know I could hack a timer into it fairly easily but that would mean voiding the warranty.

Any help would be greatly appreciated, thanks.


Where I live there is a separate metered-circuit for off-peak, so where I live this wouldn't work for you.
How about a plug-timer (you buy them and they switch things on & off), if you meter simply switches tariffs?


Before you try building a timer, see if the machine will start if you switch the mains on with the start button taped down.

If that doesn't work, you could use a 555 timer IC in monostable mode for the delay, using a potentiometer to let you change the delay. The button could be pressed by a small solenoid connected to the output of the 555 by a MOSFET. To get the solenoid to retract again, put a large-ish capacitor between it and one of the power supply rails.

That should be fairly cheap and simple to construct, and will run for a long time off of some AA batteries (how many you need depends on the rated voltage of the solenoid)

Something like this should work

The transistor on the right needs to be a MOSFET