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Lock Timer - can I do this?

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PerryGunn

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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

Perry

LockTimer.jpg
 
Looks like this is the right area as the other thread I posted has been locked - again apologies for that

Before the other thread was locked
Pommie said:
This is a mechanical problem and not an electrical/electronic problem. You seem to be trying to "fix" the wrong thing.

Mike.
Not quite... I didn't want to be too long winded with the post but mechanical fixes have already been explored and while some effect a temporary solution either the problem reoccurs or they come with 'worse' side-effects.

The binding is due to the pressure that the gate rams apply when closed - with help from the suppliers they've been fine tuned as much as possible but, at times, they still press the gates too firmly against the top/bottom stops. It's a pair of wooden swing gates so the reverse pressure against the lock changes due to the dimensional instability of the wood as the temperature/moisture content changes. The only way to avoid any back pressure is to set the rams up so that they barely close but this leaves too much play and they rattle/bang against the stops when it's windy - which will annoy both the neighbours and, more importantly, my wife :)

I've spoken to the lock manufacturer and they sell an add-on module which extends the solenoid latching time and suggested that it was applicable to situations such as mine. Great, I thought, I'll take one - however their module requires a minimum of a 0.5sec pulse to function and my control panel only supplies a 0.2sec pulse which they thought was too far outside their requirements for it to work reliably - hence why I've decided to make one myself. It's either that or replace a quite expensive electric lock that has the occasional glitch...
 
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Looks like this is the right area as the other thread I posted has been locked - again apologies for that
Actually, either thread would have been OK on its own, but two identical threads, bad idea.
Any way, no harm done, and welcome to ETO.

JimB
 
That looks good with 1 diode where you have it.
Any diode that is good for 2 amps or better will work.
 
You need an "Off delay" timer, or a multifunction timer that includes off delay.
They need a permanent power supply to A1 (+) and A2 (-) terminals.

The input signal is to S, B1, Y1 or whatever the data for the unit shows. That needs 12V applied at a trigger.

A floating contact would connect between that and +12V. or a device that provides 12V out would have its negative connection to the timer A2 terminal and the 12V pulse to B1 / Y1.

Then set the time control for the output duration you require.

Some examples that appear suitable:


 
You need an "Off delay" timer, or a multifunction timer that includes off delay.
They need a permanent power supply to A1 (+) and A2 (-) terminals.

The input signal is to S, B1, Y1 or whatever the data for the unit shows. That needs 12V applied at a trigger.

A floating contact would connect between that and +12V. or a device that provides 12V out would have its negative connection to the timer A2 terminal and the 12V pulse to B1 / Y1.

Then set the time control for the output duration you require.

Some examples that appear suitable:


Thank you, but I've already got this one from Amazon

I've already got it working with that module - tested using two car batteries and then, this afternoon, I have it working with the gate control panel using the 0.2 sec pulse as a trigger. It holds the gate lock solenoid in the open position for the configured time - currently set at 4 seconds while I'm testing, I can hear the lock solenoid trigger and then reset shortly after the gates are open.

I want to allow for failure of the 'cheap' Amazon module by sending both the 0.2sec pulse from the gate control panel and the 'longer' pulse from the timer module to the gate lock - so my question was more about connecting both 12v supplies to the lock without them interfering/damaging each other
 
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