Vehicle lights, In-cab indicators

[Johnson777717]

Ok, I'm back after a few months of time. I have an idea, and I'm a little rusty on the applications since I've had my face in a book for a few months (math).

Anyhow, I've been thinking of creating an indicator panel for my truck. What I want the panel to indicate is the status of the lights on the truck, that way, the driver knows when certain lights have burnt out, or aren't functioning.

Here is the basic concept:

The panel will have an LED for each truck light, organized on the panel to correspond with the layout of the lights. For example, the headlight LED indicators will be at the top of the panel, tail light LED indicators will be located at the bottom of the panel...so on, and so forth. The LED will illuminate when the light is on, and stop illuminating when the light is off.

I don't have the specifics on the supply voltages / current for each light yet.

This seems so simple, and I'm a little embarrased to say, but I just can't seem to think of a simple way of turning an LED off, once a light bulb has burned out. (Again, I'm a bit rusty).

Would someone mind giving me a little push in the right direction?

 

[gerty]

What G.M. (Caddy/Olds) did back in the 60s/70s was use a fiber optic cable for each light.. The fiber end was simply placed in a hole drilled into the appropriate light fixture, epoxied in place . The other was terminated at a panel that had the outline of the vehicle drawn around it corresponding to it's location. In other words there was an overhead drawing of the vehicle and where thw headlights were drawn there would be two fiber ends, which would illuminate when the headlights were on. The same for brake/turn etc...
This was a rare option , I've only seen it on a few cars. They also used fiber for dash/ashtray lights , one bulb would have one or more fibers attached to it and be used for ashtray and accent lighting...the fiber was approx 1/8 " diameter..Hope this helps

 

[Roff]

See the circuit that John1 posted at the bottom of . I love it.
I've posted the mods you would need below. You will have to experiment with (or calculate) the number of turns required to keep the reed switch closed. Unless you buy the switches surplus, I believe you will find the pull-in/dropout spec'ed in ampere-turns, so if you know how much current your bulb draws, just use a number like twice the pull-in. So, if your bulb draws 5 amps, and the pull-in is 15 ampere-turns, wind 6 turns of wire around the reed switch (giving you 30 ampere-turns).
Obviously, both circuits are series circuits, so you can arrange the parts in any series order that is convenient.

 

[tansis]

An alternative method is to use op amps, was almost positive that I had seen a quad version of this or a similiar IC, sadly not been able to find it.

https://www.electro-tech-online.com/custompdfs/2004/10/doc4775.pdf

 

[Johnson777717]

You folks are awesome! Thank you!