Modded my D4 some more. This time I added a lighted switch!
Whewwww…. what a pain! Actually burnt out something in one D4 driver during mid-assembly testing when I didn’t realize the positive and negative driver wires for the main LEDs were touching when the star was not installed. Oops! I think the FET’s gone. Fortunately, I had another driver, so rebuilt it and kept on going.
The first problem I encountered was removing the finishing washer I had previously attached to this light.
- It was attached with Arctic Silver thermal epoxy and I found I couldn’t lever up the switch retaining ring and remove the boot with the washer still in place.
- Trying to cut the arctic alumina or lever up the washer didn’t work. That glue is strong!
- I ended up having to use a hammer and chisel to get it off. Fortunately, with that method the washer came off instantly.
I had some ideas about building my own mini-circuit board for the switch LEDs out of scrap on hand. A big complication is the D4’s switch does not sit on a board. Instead it fits in a socket in the head. The switch leads come out the bottom of the switch. I needed a board small enough to fit in the light without raising above the head much.
- First I tried some thin brass sheet with a layer of Kapton tape on top. I used tiny strips of copper tape applied by hand for traces and then soldered it all together. No luck. My switch LEDs poofed… didn’t have the right resistors. Also this felt very awkward. I was worried the kapton tape might break and cause a short.
- Second attempt used a piece of 0.020” polystyrene sheet for the base with copper sheet on top. Unfortunately polystyrene has a low melting point and my board melted during soldering. No go.
- Third attempt was back to the brass sheet, this time using a conductive carbon ink pen for traces. It worked during initial testing. I then coated the works with superglue to lock everything together only to discover it no longer worked for some reason. I think the LEDs poofed again since I saw a tiny bit of smoke.
- Fourth attempt I decided to go for tried and true. I started with a basic lighted clicky switch module from I think Aliexpress. I desoldered and removed the switch and spring. Then I filed down the edges enough to verify that it could fit into the D4’s switch receptacle. Finally I drilled a whole in the center of the board, then filed it to size with a handfile. I also filed down the back of the board to make it thinner.
Here is what I started with:
And what it looked like after I worked it to shape:
The next step was to wire up the driver for the switch.
- This was fairly tricky since the open space around the D4’s driver is tiny and there are now 8 separate wires inside: 2 for the main LED, 2 for the switch, 2 for Lexel’s bezel LEDs, and now 2 for the switch LEDs. It was in doing this wiring I accidentally burned out the FET on my driver. When I redid the wiring on my second driver I covered all exposed joints with arctic alumina epoxy for extra support and to protect against shorts.
- I also needed a way to get the LED switch wires to the LEDs. There wasn’t any space around the switch, so I used a dremel to widen the sides around the switch socket, creating an opening. I coated the dremeled area with arctic alumina for extra ground protection.
- With the sides of the switch socket dremeled off I found the switch no longer fit securely in its socket. I used a little fiberfix superglue to hold it in place.
Here is what it looks like with the new lighted switch LEDs installed:
I needed a new switch boot to cover the LED. I used 1mm thick translucent high temp silicone sheet from Amazon. Thanks CRX for the tip on using Silicone sheet for this!
- First I cut a circle of silicone sheet the same size as the switch socket.
- Then I cut a very small circle to glue onto the center of the big circle to serve as the piston. I used plastic super glue activator followed by firberfix super glue. I love fiberfix because it cures instantly when you apply the little blue LED light built into the dispenser.
- With the board for the switch LEDs installed it was no longer possible to use the switch boot retaining ring. Instead, I used more plastic activator and fiberfix to superglue the big circle onto the light. I carefully went around all the edges to make I didn’t miss any cracks and the glue formed a water-tight seal.
Here is what it looks like with the silicone sheet on. I apologize for the blurry phone camera picture:
I then stuck the washer back onto the light around the switch with Arctic Silver Thermal Epoxy. Here is what it looks like with the washer in place (light is wrapped in tape to prevent epoxy getting on it):
Finally, to cover up the still visible switch and give it a classy feel I glued a circle of aluminum onto the center of the switch with fiberfix. Prior to gluing I used plastic activator on the silicone. I also filed the edges of the circle at an angle and roughened the underside of the circle to reduce the chance the circle might come off.
Here’s the end result:
It took a lot of effort but I’m quite pleased with how it came out. The switch looks and feels great and still has a distinct click. Due to the washer the switch is recessed reducing the chance of accidental activation (though not as much as the rubber boot did). The firmware is Pobel’s modified version of D4 Anduril with aux LED controls activated.