obs0lete
Posts: 3
Joined: Thu Mar 10, 2016 7:07 pm

Solenoid to push a button...help!

Thu Mar 10, 2016 7:26 pm

Hi there!

So, I have an RPi 2 Model B laying around and finally have a project I would like to use with it, but I'm not sure how to begin.
I do have a strong I.T. background but am not sure about the DIY electronics as much.
I should let you know, I have no idea how to go about this, and I will likely need some help with the setup/coding but I think this is a fairly simple project :)

Basically, I want to have a physical button (such as that on a garage door opener) pushed every 90 minutes. Simple enough (?)
From what I've researched, I will need a solenoid to act as the device that will push the button, but I'm not sure exactly what kind of solenoid I will need, how to connect it all up, coding to drive it all, etc.

Please, any and all assistance is most greatly appreciated!

Adco
Posts: 42
Joined: Fri Mar 11, 2016 3:01 pm

Re: Solenoid to push a button...help!

Fri Mar 11, 2016 7:57 pm

Why do you need to physically push the button every 90 seconds? Can't you set up a timer to "push" the button in software instead?

obs0lete
Posts: 3
Joined: Thu Mar 10, 2016 7:07 pm

Re: Solenoid to push a button...help!

Fri Mar 11, 2016 8:33 pm

Adco wrote:Why do you need to physically push the button every 90 seconds? Can't you set up a timer to "push" the button in software instead?
Thanks for the reply Adco.

The button I am trying to push is a physical button on child's toy, that auto-shuts off after 90 minutes but if you press a specific button on it, it will reset itself and run another 90 minutes until it either shuts off or that button is pressed again.

I'm not looking for hand holding (would be nice!) but at least a way to get me started with this project.

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Burngate
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Re: Solenoid to push a button...help!

Sat Mar 12, 2016 10:55 am

Pimoroni sell a solenoid for £6, which may do the job.
https://shop.pimoroni.com/products/mini ... GwodvcoPCQ
It has a throw of 3mm, and 80g, which would probably be overkill for what you want.
It takes 1.1A at 5V, so you would need to power it separately from the Pi, and drive it from a transistor.

Smaller solenoids are probably available, though probably not much cheaper.

Sonny_Jim
Posts: 45
Joined: Tue Oct 23, 2012 4:15 pm

Re: Solenoid to push a button...help!

Sat Mar 12, 2016 11:01 am

Solenoid sounds like absolute overkill tbh. Personally I'd either use a relay hardwired into the button or just pop the toy open and swap out whatever capacitor drives the timing circuit so something else.

obs0lete
Posts: 3
Joined: Thu Mar 10, 2016 7:07 pm

Re: Solenoid to push a button...help!

Mon Mar 14, 2016 1:30 pm

Thanks all for the replies!

It looks like a Solenoid may be to much based on the responses, so i'm going to take a look at the suggestion posted by Sonny_Jim and see if I can make sense of this. I'll post with any questions.

Thanks again!

Adco
Posts: 42
Joined: Fri Mar 11, 2016 3:01 pm

Re: Solenoid to push a button...help!

Mon Mar 14, 2016 6:42 pm

I think a RPi is way over the top to do this job. Depending on the accuracy needed, I would either use a dedicated cmos type "counter" or a PIC chip like a 12fxxx. Depends on the person electronics abilities. Then I would either drive a transistor across the push button or drive a relay contact onto the switch. Again, depends on the person's experience. To use a RPi for this job is like hunting for rabbits with a guided missile.

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