Help me design a simple time delay (not electrical)

[supak111]

Hey everyone I'm trying to design a simple time delayed device. Device could me mechanical but it doesn't really have to be as long as it does what I want.

Just need something that is relatively small could be wide and tall just not thicker then 1 inch.

The device should have a arm/button that you can push down (1 inch travel at least), when you push the arm/button down it should stay down for about 2 minutes and then come out and have enough push power to push up something that's about 1/2LB. The arm/button that does the pushing/work can come out slow or fast

 

[DaveC426913]

I smell a Hallowe'en prank!

 

[supak111]

No actually but now that you mention it, that sure would be a good device for Halloween. Do you have any ideas on how this could be achieved Dave?

 

[DaveC426913]

I've been giving it some thought but nothing yet.

 

[phinds]

You could build a watch escarpment but that's not exactly simple

 

[supak111]

Yea. I was thinking maybe something with cylinder, spring, air and a one way valve. Kinda how the screen door closer works but flipped around. If I made the one way valve leak air a tiny little bit it would take a long time before the arm comes back

 

[David Lewis]

When you push the output arm down, it compresses a spring and then latches (jack-in-the-box mechanism). The latch is released by a wind-up clockwork timer.

 

[Ranger Mike]

dashpot

 

[Nidum]

mechanical but it doesn't really have to be as long as it does what I want.

There are lots of simple 555 timer kits on the market . Use one of those for timing and add a power stage or a relay .

 

[David Lewis]

The simplest and cheapest non-electronic may be kitchen, toy (e.g. Tomy), or model airplane de-thermalizer timer (e.g. Tatone). Even cheaper is Silly Putty timer. The release string slowly drags through the putty.

 

[supak111]

Don't really want to use 555 timer because its electric and won't be dirt cheap. Dashpot is too expensive and complicated, I want to keep this under a $1 if possible.

Lewis I found a lot of info on all 3 you suggested but can't really use them. My device MUST be easy/fast to push down but then it doesn't matter if it release slow or fast.

I had someone suggest a simple suction cup because he saw it used as a time delay in a bathroom paper towel dispenser. Idea like that sounds perfect but can't seem to find one that has 1" or move of travel for cheap.

 

[rootone]

Maybe you could use sand or a similar dry powdery material.
When you open a trapdoor it will flow through the gap until it's all gone, and then a small spring pushes the trapdoor back to original position.