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Help with a simple circuit design

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FireAce

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Greetings friends, need help designing a simple circuit, I have no idea how to go about it.
What I'm looking for is this. I have a motor opening and closing a gate on a N scale coal loader. As you may know, N scale is fairly small so I have little working room.

I wish to have a push button that once pushed and held, will power motor for, say, 1 second. Enough to open gate. Once, and only once button is released, the motor will run the opposite direction for 1 second or less.

I will probably use 2 relays for an H bridge, and I love 555 IC's, so help me out if you have any bright ideas!

Thanks
 
I personaly prefeer HO but the choice is yours. What you are suggesting is something that is not going to be easy to do with such little working space. Something simple would be to have a simple transistor inverter driving one side of your H-Bridge and the other (which would be what opens) would go through a 555 timer or such to creat the delay. This would allow you to push the buton and the 555 would run for a certain time before stopping. Relesing the button would allow the unit to close until alimit switch is triped.

May I ask why you didn't just go for a limit switch for opening instead of a time delay?
 
I wish to have a push button that once pushed and held, will power motor for, say, 1 second.
How long should the motor run for if the button is held for much less than 1 sec (say 0.2 sec) ?
How long should the motor run for if the button is held for much longer than 1 sec (say 3 sec) ?
 
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Thanks for the replies, I sold my N scale and am now building loaders and dumpers for both scales. My next layout will be HO.

I limit switch is doable for the open gate limit. It prob woudnt work for closed, as "coal" may keep gate from fully closing, even though flow is stopped.

Run time is flexible, the drive system is belt run, and is allowed to slip once gate is open or closed.

So I will go with limit switch on "fully open", and once button is released would then need motor to run opposite direction for 1 second. PC board can definitely be place externally of unit, like under layout.
 
Here's a 1 second (adjustable) timer which is triggered when the button is released. The only active component is a quad NAND Schmitt (CD4093). Sorry, no 555 :).
 

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If you can add an auger screw then you can have it run so that "coal" can flow out of your hopper (I'm assuming that's what it is) and when it stops, it keeps any more from flowing out, and what ever is below the auger screw is free to exit the hopper before the door closes.

alec_t's circuit will definitely work if you want to use it.
 
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