We made a custom bracket out of thick aluminum stock, following the contours of the skull. It was painted black to hide the bracket. Very cool - it looks like the chrome skull is floating in the back window.

But wiring it was interesting. We found that only one connection actually did anything as far as lighting up the eyes. The rest of the wires from the flat connector did zero (except the ground wire).

This was NOT cool, because we wanted to multi-task it. Running lights, brake lights, possibly turn signals as well.

What we found is that a 3K ohm resistor was needed to connect the running lights, and that each wire had to have a DIODE installed in it.

A diode is an electronic device that only allows voltage to run in ONE DIRECTION. This was needed to keep the turn signals from becoming HAZARD flashers, and also to prevent the running lights from over-riding the turn signal flasher.

Three wires are needed.

The running light wire has 3K of resistance in it, and a Diode.

The left and right turn/brake wires have a diode.

We nabbed the diodes at radio shack - 3 amp 200 volt rated just to be sure. ($1.29 a pair)

The striped end of the diode should be installed on the side towards the skull. Think of it as the negative side.

We used jumpers to try different resistors until we found a set that made the eyes of the skull light dimly when the running lights were on, and became bright when either the brakes or turn signals were used.

The next project calls for using a pair of these on a 1950 Chevy truck as tail lights, so that application will be slightly different.

Again - although the hitch cover has a flat trailer connector on it, only the white (ground) wire and the brown (running lights) wire is connected to anything.

All of the above was installed in a 1950 FORD 2 door. One wire runs from the running lights, with a resistor and a diode. One wire each with a diode in line with it runs from each rear turn signal/brake wire.

The install went smoother than cookies and cream...

Pictures later, it's miller time!!!

 

Sounds pretty sweet, looking forward to some pics! Do you have it setup to flash or just steady on?

 

States of activety:

(Lights off)
TS on: Skull eyes flash
Brakes on: Skull eye lights bright
Brakes + TS on: Skull eye lights bright

(Lights on)
No input: Dim eye lights
T/S: Skull eyes lit dim, but eyes flash bright
Brakes: Eyes go bright
T/S + Brakes: Eyes lit bright

This is the reason we put a resistor in line with the marker lights - we wanted a difference between signals and just plain lights.

The resistor makes the marker lights dimmer than a brake or turn signal light.

The problem here was that the same connection was supplying power from the turn, brake, and marker lights. We had to reduce the current from the marker lights using resistors. This brought the voltage down, so it reduced the power.

Putting it simply - one of the inputs had to be reduced (the markers). So we limited it. The others are straight 12 volts.

If we did not limit the juice from the markers, they would be the same intensity.

- I hope that makes sence to you

 

Yeah all makes sense to me (electrical engineer), Was just wondering if you added a timer or a flasher circuit like a 555 timer to make the leds flash rapidly, several times a second. But I do like the idea of lowering the intensity with the running lights.

 

We kept it very basic. There's no need to modify the flash rate in this application.

If I did want to do that, I'd setup the timer circuit to replace the T/S flasher unit itself. But this way everything is easily replaceable, flasher goes out - head to any parts store. The wiring and components are purposely heavier duty than needed so they will last.

 

Pictures of the project showing the bracket that we made

 

I like it! that is definately trick, it does look like it is floating from the back.

 

Cautions when working with Aluminum plate:

Avoid grinding aluminum on a bench grinder - it's a soft metal and can cause the stone to explode.

A saws-all can remove most of the metal at odd angles if you make several cuts from different angles. Sort of like making chisel cuts.

Once you make a bend (unless you "aneal" the metal first, which softens it) consider it BENT. Aluminum will crack if worked too much. Don't go back and forth...

YES, aluminum does conduct electricity. But run a ground anyway - dissimilar metals can lead to corrosion and mess up continuity.

Wire wheels are the BOMB for smoothing cut edges... You can carve soft aluminum with a wire wheel, so be careful how much you take off.


~Wolf

PS: I'll drop two more pic's here showing it lit up later on.
PPS: In the '50 Ford, the brake lights are on the same wire as the turn signals.