Medieval Madness Troll Eyes Mod

So I decided to put LEDs in my troll eyes. The first step is getting the LEDs into the eyes themselves. I chose not to add any other circuitry in the head; the head gets beaten about, so the less joints the better. My initial plan is to run off of  the troll hold coil. That's going to mean about 70V, so we'll be using a 4k7 resistor to limit the current, and a diode to protect the LEDs against any unforeseen happenings.

I prefer the greater robustness of red LEDs for this mod. And Pam says that the red LEDs look better in the game. Using the hold coil keeps all the wiring inside the assembly. If I was inspired, I would rewire the power connector and add a Molex disconnect. But I am not that inspired right now.


4x red LEDs (two spares recommended in case something goes wrong)
3" of 1/8" heatshrink
8" of3/16" heatshrink
2x 4k resistors - these should be 1W parts. 1/4W - surprisingly - is OK, but will get ugly in the long run.
1x 510R resistor (for testing)
9V battery - also for testing
2x 1n4007 diodes
6 feet 24GA stranded wire
4 small tie wraps

We have a kit for all this stuff on Pinbits. The wire that we have there is Troll green 24GA teflon coated 19 strand wire (compared to 7 strands for regular wire). It is even silver plated, but that doesn't matter here. the reason to us it is that the extra strands make it extremely flexible, so that it won't mind all the movement for the carriage. Also, the Teflon jacket won't run away from your soldering iron - which makes for nice-looking joints.



First, we have to drill the eyes out. I used a 0.116" drill. This is about right for snug LEDs. 7/64" is the closest common size, which will be a little bit tight, but the vinyl stretches easily.


Drill in the middle of the eyeballs. Drill straight down, you want vertical holes. Here you see the LEDs ready for bending; set them up with the flats to the left. Get the drilling burrs out from the inside of the head, they will be a nuisance otherwise..
Stick the LEDs into the outside of the troll's face, with the flat sides / short legs to the left.


Cut the left leg of the right LED about 3/16" up. Bend the right leg of  the left led down, and create a little loop around the leg. trim the end of the loop and the end of the leg.
Remove the LEDs from the face. Soldering iron scars will not look good on your troll. Separate the wires, and slip a piece of heatshrink over the long leg. Connect them back together, tighten the loop, and solder. Be quick: these little LEDs don't like overheating. Attach wires to the outside legs and put heatshrink on them. I do this by tinning the wire and the leg, and then soldering them together along the length of the wire. Cut the black wire that goes to the flat side of the LED a little short so that you will recognize it- this is the negative lead.


Put one last piece of heatshrink over the wires, and make a triangle. Tighten it all down with some hot air. Finally, work the LEDs into the eyes from behind. By assembling them to the face of the troll, you set the spacing right, but you still may need to bend them a bit to get them in. Push them deep into the hoes using a screwdriver as a lever. Pull the wires through the hole in the bottom (you may have to open it up with a screwdriver). Push the wires towards the front of the head.


Here's the finished head. I filled the lower half of mine with silicone to hold the LEDs and wiring in place, it is going to be taking some action. I also put a blob of silicone in the exit hole. Test your wiring by hooking the wires up to a 9V battery and the 510 ohm resistor. The long wire is positive.


Now you can re-install the head. Run the new wires underneath the chin, away from the switch blades, and along with the switch wiring. Put a piece of heatshrink on the wire where it touches the carriage, and tighten it and the switch wire down with a tie-wrap
Next, the wiring. Trim both wires to be about 5" longer than the run to the solenoid.  Keep track of the positive wire. positive wire Then, we need a 1N4007 and a 3k6 resistor in the positive lead, wired in the order shown. Your resistor may be a different color (our current inventory has a brown body, and the test resistor is blue). Make little links out of the wire and solder the parts together, we want tight joints.


Slip about 3" of 3/16 heatshrink over the wire and resistor assembly and solder the resistor end to the red (right hand end) wire on the flipper coil.
Pull the heatshrink tight to the terminal lug, heat it up and lock it down. Tidy it all up with a tie-wrap. You should have a nice loop that readily accommodates the carriage motion.


Put the troll in the machine and test it out - if you removed the flap, don't replace it until you have it all working. Then, don't forget to connect up the troll target switch and the troll up switch. One down, one to go!