Mk5 LED Cupcake lighting
by natko, published
Since finishing my spool box my desk lamp no longer lights the platform.
I looked at lighting in Thingiverse but the solutions required parts I didnt have or the Mk4 Plastruder.
So heres my attempt using two led torches from the local store, some 15A fuse wire, and a 9.8 ohm resistor.
WARNING DO NOT CONNECT TO YOUR POWER SUPPLY WITHOUT A CURRENT LIMITING RESISTOR, IT WILL RESULT IN AT LEAST 1AMP CURRENT DRAW. (Warm cables to say the least).
And for the electrical engineers out there, yes you are not supposed to connect LEDS in parallel without individual resistors.
Although you can get away with it if they are the same type of LEDS in my mind (thus I bought 2 off same type torches).
Print out the plastic thing.
Remove LED heads from torches, (they push out the front, so a bolt or somet that is longer than the torch body is ideal to push it out against the floor, maybe a bit of tapping with a hammer too).
With soldering iron and flat screwdriver price out your leds from the PCB, its easier if you have someone to hold the PCB or use a vice.
Push the LED's into the plastic thing, YOU WILL NOTICE A FLAT EDGE ON YOUR LEDS EDGE - FACE THIS TO THE CENTER/CENTRE OF THE THINGY. This will put the cathode (negative legs) all around the inside rim.
(You might have to ream the holes a little, I used a 4.8mm drill bit)
Using the fuse wire or what ever wire you got solder the inside ring and seperately the outside ring of legs (see picture). I found putting a loop around each LED pin stub a help, but makes replacement of a single LED a pain.
Connect your cable and insulate so it cant short (remember you risk your power supply.
Connect the other end, again see picture, I worked out that the 9.8ohm resistor should result in about 158mA (0.8W) consumption (measured about 120mA). Now you may spot that I used a 1/4W resistor (its all I had), if you can, use at least a 1/2Watt. Mine works but gets a little warm, its been running now 12Hrs and seems stable.
Please remember though you must use a limiting resistor.
Test, I used the battery pack out of one of the torches to test the ring's prior to fitting the resister, possibly a good idea as I had fitted one the wrong way round and another I had knackered when removing from the PCB.
Plug into your power supply, making sure you connect positive (outer ring) to red wire on molex connector (+5V) and negative (inner ring) to black on molex connector.
Initially just keep your eyes open make sure you dont let the magic smoke out and check your cables/resistor are not getting warm/hot.
If ok, remove the plastruder head from Z axis table, slide plastic thing into the U slot with the pin going to the hole drilled in the table, it should just pop in to the hole holding the lights in place.
Run your cable as suits, and thats it.
My system has the thermal tape fitted, I would not suggest using this thingy on an un-insulated head.