Using a traffic light to help parking the car in the garage

I'm not sure where your light was sourced from, in the UK older systems used 12v capsule lamps with local transformers in the head.

You could localise the relay control and switch 12v instead of mains voltage.

Also worth considering is the operation where a lamp has failed. If the red light has blown you may end up with a dented car.

I'm not sure where your light was sourced from, in the UK older systems used 12v capsule lamps with local transformers in the head.

You could localise the relay control and switch 12v instead of mains voltage.

Also worth considering is the operation where a lamp has failed. If the red light has blown you may end up with a dented car.

It's a US traffic light that, currently, uses fairly low wattage 110V lamps.  I built up a circuit many many years ago with a couple of 555's and (I think opto-isolated) SCR's just to have each of the lights flash in sequence (RED ... yellow ... green).  Now, with a garage, I'm trying to make it more useful.

And, yes, the failed lamp scenario could be a problem.

You could look into drop-in LED replacements for those lamps. What kind are they?

If the red light has blown you may end up with a dented car.

You could always check if the lamp is okay and flash all the remaining lamps at the same time to show an error.

Obviously you'd need some form of microcontroller.

Many of the automotive computer modules do something similar and throw an error.

Mark

Good Idea! could something like the ACS712 be used?

Good point although many have LED arrays in now.(At least  here in the UK)

One way of dealing with that is to light all 3 colours and then as they go past certain proximities switch off the Green and Orange until only the Red is still on and you need to stop

I took a peek at the bottom "green" lamp.  What I found currently in the socket looked like a standard A19 base with a small Westinghouse 15W "Industrial" lamp.  I can't recall if that was the original lamp or one I had/found with a lower wattage.  In any case, going with LED's as a few have suggested is an interesting idea.

That's a great suggestion regarding having all lamps on and turning off green and yellow as the vehicle approaches.  That would also give a visual indication that all lamps are working before the vehicle gets too close or things get expensive...

Paul

This device (please include a reference link next time) is a current sensor, and would work.

You would need to power the lamp to get the current flowing.

Most methods I've come across simply use a fairly high source resistance and detect if the load pulls it to ground.

If the circuit uses an open collector arrangement, then there wil be voltage at the collector if the load is present.

You could use an optocoupler across the collector to emitter, which will conduct if there is power and the load is present (it will be off when the transistor conducts)

So you have a double detector. (Load/lamp present and Switching works)

If Allen has an idea of how he wants to configure it, what voltage/type of lamps then we can suggest some ideas.

I think these will be cheaper than the current detector.

Mark

I'm sure we'll need one soon I've just ordered Elite Dangerous and I've heard some of the big spacecraft are a bugger to park

Since I've got 3 operational (110V) lamps and with the current sockets/wiring already in place I'm inclined to just add the proximity logic ... and switch the lamps with relays, SCR's, ...

Not sure that I need to go full out and detect when one of the lamps has burned out.  I'm also not sure I want to change the Green (GO), Yellow (SLOW), Red (STOP) pattern.  But, I can mix things up a bit and add a 4th pattern of Green/Yellow/Red -- All FLASHING -- for "NO, SERIOUSLY, STOP".  The question to answer here is how much granularity (feet or inches) will I be able to get from the ultrasonic sensor?