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Lock Timer - Can I do this?

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New Member
Apologies for posting this in two areas - I wan't sure which was the appropriate one

Background - 'cos it always helps

I have some electric driveway gates with an electric lock and sometimes the lock doesn't disengage properly. I've troubleshooted the issue and it appears that sometimes the lock binds slightly on opening and doesn't spring back. As soon as the gates start to open (about 1 sec after the lock should have disengaged), the binding pressure on the lock is released and, if I'm standing there next to it and press the manual release button, the lock will spring open and the gates can operate as intended. If the lock binds and the manual release is not pressed, the gate motors are pulling against the lock and I've already experienced some gate damage due to this.

The gate control board (in the garage) sends a 0.2sec 12v DC pulse to energise the solenoid and disengage the lock, this means that, when the lock binds, the solenoid is no longer energised at the point the gates try to open so even though the binding pressure on the lock is released it is in the 'locked' position. If the solenoid activation pulse was longer, say 2-3sec, the lock would release as soon as the gate starts to move and the binding pressure is released.

What I'd like to do

Extend the lock solenoid activation period to around 3sec using the 0.2sec pulse from the Lock Control Module as a trigger

How far have I got

It's been a long time since I've done much in the way of practical circuit work but I can create an extended 12v pulse by using a timed relay taking power from an independent 12v power supply (thinking of a 12v 5A laptop supply), and using the 0.2sec 12v pulse from the Lock Control Module as the trigger. I've tested the timed relay hookup using one old car battery as the trigger and another as the power supply (don't see why the laptop supply won't work) with a 12v lamp as the load, and I can generate timed 12v outputs

What I would like to do is take a 'belt & braces' approach and connect both the Lock Control Module and the timed power to the lock so that if there is a problem with the relay board the lock will still receive the pulse from the Lock Control Module - this is shown by the blue and red lines below.

In order to do this I think i require a diode on the +12v line to isolate the two power lines. Is this correct?

- Do I require one on the -ve line as well?

- What size/rating diode would be required?

- Am I barking up the wrong tree and this won't work?

Thanks in advance


View attachment 126390


Well-Known Member
Most Helpful Member
This is a mechanical problem and not an electrical/electronic problem. You seem to be trying to "fix" the wrong thing.



Super Moderator
Most Helpful Member
Apologies for posting this in two areas
Please do not do that.

It only creates confusion, some people reply to one thread, others reply to the other thread, and the whole thing turns into a bit of a marmalade.

I am locking this thread.

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