Introduction: Adding Led Eyes to the Mack Bulldog Hood Ornament
The bulldog hood ornament is on just about every mack truck across the globe. I managed to get one, mount it on a jeep, and led lights for eyes. This instructable explains the led mounting procedure in non technical terms so your rig (or bike, kayak, dune buggy, etc) can have glowing eyes.
Step 1: Procurement and Parts
the mack truck bulldog hood ornament is available for purchase on ebay or online
I purchased it 6 years ago at a tour of the mack truck factory for 30 dollars at the time. it might also be a good idea to find a big scrapyard and check.
i used 3mm (aka T1) bright led's check mouseror digikeyfor the brightest ones available for the color you choose. 5mm led's would be too big and look dorky. its also good to use clear led's so that when the eye's are off they look like part of the silver structure, not little red dots. resistors can be purchased at radioshack or along with the order.
Current Limiting Resistor
the resistor value you use is dependant on the led used and the power supply for your vehicle. for an led with a vd or forward voltage of 2.6 volts and an id or forward current of 20 milliamps (see datasheet image) and a vehicle with a 12v supply here's the procedure for determining the correct resistor value
(vehicle voltage - vd) = vdrop so:
12v-2.6v= 9.4V= vdrop
using R=(V/I) substitute values in place
R= 9.4V/ 20 ma = 9.4/ .02
so R = 470 ohms
the power dissipated across the resistor is calculated from P=IV
.02*9.4=.188 Watts , so a 1/4 watt resistor (common at radioshack or real electronic parts store) is ok to use. chances are a 1/2 watt resistor might be better suited as the resistor wont be able to dissipate much heat into epoxy.
Step 2: Drilling and Mounting
first off i placed the bulldog between 2 pieces of scrap pine wood to prevent scratches.
Its important to note that the back of the bulldog is hollow, probably for this purpose. I drilled out the eyes using a 1/8th drill bit and moved around until the led i chose could fit through snugly ( all the way through)
Step 3: Assembling the Circuit
this is really simple, the positive side of the led for each eye consists of the following shown below.
connect the ground to the frame of the bulldog via soldering with a hot soldering iron / solder gun. you have the choice of running either 2 or one switched lines up to the bulldog (if you want one to blink while turning or something) i used lamp cord for the automotive wiring
Step 4: Finishing Up the Lights
after soldering the led's and resistors wrap everything in electrical tape or heatshrink to isolate from the bulldog metal frame.
feed each one through and test each with a 9v battery (yes they probably still work at 9v too) or 12v supply.
to ensure that the led's stay in place i packed all the wiring inside the head with hot glue to temporally hold everything together. ensure that everything works, because the next step is to epoxy everything together. bang it with your fist, shake it make sure there is no flickering, nothing is more ghetto than a one eyed bulldog hood ornament.
also drill a hole for any power wiring (switched lines)
using a piece of broken bike tubing, i cut a piece that covers the bottom, remember to leave a spot for the power wiring
Step 5: Epoxy and Mount
fill empty area with epoxy and let dry
begin to mount the hood ornament. this requires drilling through your vehicle's hood (or your kayak) .
It took a few seconds to realize wow, im drilling through the hood. at the time i saved up and had the vehicle painted at an overnight re-spray warehouse in Brooklyn 4 months earlier (by a guy only known as big vinny) for this step its important to Take your time and not screw up.
drill through the hood at a predetermined point from the top, and file out the necessary distance so everything mounts properly, also drill for the switched power line.
mount everything and run the necessary switched power from a fused power line. make sure there is a fuse!
mount a switch and wham, your rig, kayak or jeep now has more testosterone.
Step 6: Vehicle Wire Harness and Switch
After completing the mounting, running a switched line to the hood is relatively simple. on most vehicles, the hood has reinforcement (see image, showing ribbed reinforcement thing under the hood)
There are already holes there from factory production, try to take advantage of them and use them for securing the switched line. keep in mind, separating the vehicle (ground) from the wire is very important!
Step 7: Final Product
Here's the results: