As you know, I like building dumb projects using junkyard parts, particularly when they're all about safety! This tale of building your very own Skull Brake Lights has more than the usual twists and turns, so buckle up!
(In honor of Halloween I resurrected this greatest hits piece after Murilee asked if we could reformat it so it worked better on the new site so he could post it on his awesome personal site. Did anyone try this? Not sure why we're all about custom posterior lighting lately. Enjoy — Ed)
It all started about two years ago, when I caught the 24 Hours Of LeMons jones, bad. How bad? Bad enough to put a team together, drop a Ford 302 in a Volvo 244, and enter the notorious Altamont "Demolition Derby" LeMons race back in early '08. With a Scandinavian Black Metal theme, the car needed to look evil! And thus began the saga of the Screaming Skulls...
Nowadays, my beater '92 Civic sports a pair of clattery, chattery "talking" skulls that use up pretty much all of the hatch area's storage capacity. When I hit the brakes, the jaws open and close (with enough force to bite through a celery stalk; yes, I've tested the bite power) and the eyes gleam a menacing- yet safe- red.
They're loud and annoying, but totally worth it. All it took was a few bucks in parts and hundreds of hours of time.
First, I needed a couple of plastic skulls. It turns out that "factory fourth" med-student skulls are dirt cheap on eBay. They're cheap because they tend to have different colors for the cap and face, or maybe some missing teeth, or just ill-fitting parts. None of that mattered for this project, so I ordered two right away.
My initial plan was to use vacuum motors, or "suck power," to actuate the jaws. I grabbed a couple of heater-vent vacuum actuators from a Chevy Astro Van and started cutting holes in the skulls. They're made of very dense, heavy plastic that's quite easy to drill, cut, and grind. I started the project by drilling out the eye sockets and cutting another hole at the base of the skull for the steel pipe that will form the "neck."
The illuminated red "eyeballs" were made from a pair of steel-and-glass Alfa Romeo warning lights, pulled from junked Alfa Spiders. Junkyard tip: always grab these lights when you see them; the quality is excellent and they're easy to mount on your homemade instrument panel projects.
The jaws on the cheapo plastic skulls don't include a reliable hinge mechanism for the jaw, so I went with a homemade rod-and-tube arrangement. Drill some holes, push the pipe through the jaw holes and a piece of tubing, then JB weld the ends in place.
Here you can see the pipe T fitting epoxied into place at the base of the skull, as well as the installation and wiring for the eyeball lights.
The Astro Van vacuum actuator goes into an aluminum spacer plate that mounts between the skull and its lid. There's a rod going down to the jaw. During high vacuum (engine deceleration), the actuator will suck the jaw closed; mash the gas pedal and the resulting low vacuum will let the springs pull the jaw open. Now repeat these steps with a second skull!
We mounted the skulls on the car's roof, hooked them up to a vacuum port on the intake manifold, and went racing. The skulls worked, but the jaws only opened at WFO throttle and it was a chore to get the springs adjusted for the correct tension. Clearly, I'd need to go to electrically-operated skulls next time!
I didn't have to look far to find electric actuators for the upgrade; most Volvo 240s came standard with power door locks. I sold the actuators that came with our car to meet LeMons budgetary requirements, so I had to hit the junkyard to get some more for the skulls. Here's a promising candidate!
Here's a mugshot of a typical Volvo 240, to make your junkyard shopping trip go faster.
First step is to remove the window crank, armrest, and door panel.
There's the actuator! A few turns of the wrench and a snip of the cutters and it shall be mine.
Voila! One more and I'm done.
My junkyard shopping isn't through yet, though; I'll need some relays and a turn signal flasher to create the "brain" that will control the skulls. Next stop is a 1980s BMW for some Bosch relays. This E30 looks promising.
There we go! This project requires three SPDT relays per skull, for a total of six. No problem finding Bosch SPDTs on an E30- just look for the ones with five terminals, including two labeled "87a" and "87b." As for the turn signal flasher, I like the old-fashioned cylindrical ones from pre-1990s Detroit cars; these skulls will use Chrysler K-car flashers.
The control circuitry is pretty simple: the power to the eyes and the coil of Relay #1 goes through the turn signal flasher (I added a taillight bulb, labeled "Load Bulb" in the diagram, inside the skull to provide enough current draw to make the flash rate a bit faster). When the coil on Relay #1 activates, it causes the coils of Relay #2 and Relay #2 to activate, which reverses the polarity of the power leads going to the lock actuators in the skulls. This causes the actuators to deploy down ("lock") as well as up ("unlock"), which means springs won't be necessary to close the jaws.
Speaking of jaws, I decided to improve the linkage with a double-jointed arrangement.
Some modification to the lock actuators was necessary to attach the jaws.
Now it's time to start playing with wires.
Here's a quick bench test of the circuitry. Hey, it works!
And it works when installed in the skull, too!
There's just enough room in the skull for the relays, flasher, lock actuator, wiring, and load bulb.
It's going to be a tight fit to get the lid installed, but it should work.
And remember, everything has to be done twice!
For Black Metal V8olvo Mark II, I decided to get some anatomically correct plastic skeletal arms (also cheap on eBay) and rig up the skulls so they appear to be backseat passengers. Add a T-shirt and it looks pretty good.
I hooked up the wiring to what became known as "The Metal Switch" on the race car's instrument panel. Pulling the Metal Switch activated the skulls and caused Opeth to crank from the in-car PA system. Oh, they'll love this at the track!
Some cheap blond costume wigs gave our skulls more of a "dead Swede" look. Add some evil black robes and spiked Hammer Of Thor V8olvo medallions and we were in business!
It looked great on the race track!
I'd be going on to a new theme for the race car, so the skulls were retired. What to do with them? I know- brake lights for my Civic! First step was to find an unused circuit in the fusebox to get some power. There's no sunroof on my car, so the sunroof fuse it shall be!
It would probably be more sanitary to tap into the brake light switch at the pedal, but that would mean running more wires to the back of the car. Instead, I'll just splice into the taillight wiring harness.
Since I've got junkyard relays all over the place, it's no problem to find one to actuate with the signal from the taillights. This will go in the spare tire well in the hatch.
A little carpentry work will be needed to mount the neck-pipes in a way that will be visible in the car's back window.
Because safety is so important, I'll use these long bolts through the spare tire (which is clamped to the floor) to hold the Skull Shelf in place.
A couple of wingnuts and it's fixed pretty firmly. As long as I don't wreck at a speed above, say, 15 MPH I shouldn't get bashed in the back of the head by 30 pounds of plastic skulls. Don't try this at home unless you find some way to mount the skulls more solidly.
I don't want the wigs coming off the skulls when I open the hatch, so a few hairstylist-approved sheet-metal screws will ensure that they stay in place.
Because following drivers at night won't be able to see anything of the skulls but four glowing eyes when I hit the brakes, I'll need to illuminate their faces. The rear side marker lights from a mid-80s BMW 7 series are just the right size, so it's off to the junkyard for some more shopping.
Some coat-hanger wire and an easy wiring job and the face lights are in place. I'll bend the wires so that the lights will be hidden below the edge of the window, out of view of drivers behind the Civic.
Here's the shelf installed in the car. I've cut holes in the hatch floor and carpeting for the mounting screws, and the wiring harness connects to the skulls via a 2-pin connector, making it easy to remove the whole unit when I get tired of the lack of cargo space.
The skulls look good installed, although the noise they make when I hit the brakes is a bit maddening. Sort of a "Ka-CLACK! Ka-CLACK! Ka-CLACK!" racket, which irritates nearby drivers nearly as much as it irritates me. The slightly different cycle rate for each skull's turn signal flasher means that they rarely sync up.
The whole rig looks quite snazzy. Amazingly, I rarely get pulled over by Johnny Law while driving this fine automobile.
My long-suffering neighbors have given up any hope of me ever driving a nice car. I like to get their hopes up by bringing home the occasional brand-new press car... which then leaves a few days later.
One skull has a ponytail, so you can tell them apart.
Here's what it looks like at night. Success! The puzzled looks I get from tailgaters are worth the effort... maybe.