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Two normally closed switches with timer and OR gate

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Newbie level 1
Aug 9, 2015
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I am a hobbyist. I have used automation systems and repaired damaged PCBs and stuff, but my training is limited to a course when I was about 10 years old which was a long time ago. Usually, I am a hobbiest out of necessity. I used to have some nearby friends to consult about issues, but we moved. I am hoping to find some assistance here.

Context: I have a commercial garage door opener. It operates perfectly when opening. Closing is now an issue. When I push close, it will not stop trying to close. It has two normally closed switches in the circuit. Both switches are operating perfectly. Without a switch in the circuit, nothing operates. I have concluded that the logic chip on the circuit board is damaged. I cannot find the logic chip to purchase anywhere. The circuit board was discontinued and the replacements costs $150. which is more money than I can afford right now.

Solution: Break the circuit at the point of the switches and create my own sub-circuit. The sub-circuit would simply break the 110V supply (relay) when either switch A or switch B is tripped. The circuit would break for 4-10 seconds then return to normal state.

HELP: The concept seems simple in my mind. I have the two NC switches. I just do not know what to insert for the OR logic or timing. In my mind, the following is the logical circuit:

Thank you for the help!!

Does your mechanism have the setup I've seen, where a light is mounted on one rail near the ground, shining on a photosensor at the opposite rail near ground? These prevent the door from closing if anything obstructs it.

Is your door controlled by the same setup? If so, then you might attach some kind of opaque shield on the door, so that comes down and blocks the light at the proper moment.

I forget if it would also prevent a door from raising. If it does then you'll need to custom shape the shield, or cause it to pivot out of the way, or somesuch.

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