Some month ago I made the mistake to park my bike at our local train station. After some hours I wanted to pick it up again and sadly found it without the saddle and the taillight.

I bought an new saddle but still the taillight was missing. Last week I found an damaged solar garden light and I was wondering if I could convert this into my new back light.

So I started my new project:

Step 1: Materials & Tools

Materials

1 damaged (the electronics still worked) solar garden light
1 rear reflector
3D-printed parts
hot glue
solder
zip tie

Tools

caliper
precision screwdriver
wire cutter
soldering iron
3d-printer
pc with some CAD-software (I used RHINO 5)
hot-melt gun
file
hammer
cotter pin drive
drill
metal saw

Step 2: Disassembly the Solar Garden Light

To dissemble the solar garden light was a little bit tricky because the main parts and the wires were glued together with hot glue, so I had to be very careful not to damage the elctronics and the wires.

Step 3: Modify the Housing

I tried to use the most of the available parts of the solar light and so I took the main housing with the solar cell, the elctronics and the storage battery and modified it to hold our new led socket.

I used an 8mm wood drill because of its top (you can better center up while you are drilling).

Step 4: Building Our LED-Socket

To built up our new led socket I just cut of the old one with a metal saw.

Step 5: Modify the Electronics

In this step I had to connect the shortend wires with the led by using my soldering iron. It's important that you wire the battery and the led in the right way (+ to +, - to -), otherwise you can damage the led. You also have to notice to put the heat shrink tube over the anode and the cathode of the led before you wire it.

Step 6: Preparing the Housing

I used hot glue to combine the led socket with the main housing. I also had to use some hot glue to put the battery in the right position. The housing was a little bit damaged and I fixed it like that.

Step 7: Preparing the Rear Reflector

After I had assembled the main housing I had to brake the housing of rear reflector to get the round red reflector disc.

Step 8: Assembly of the New Rear Reflector Housing

After measuring the dimensions of the reflector disc I created the new housing by using RHINO 5 and a 3D-printer. It consits of 2 parts which are pushed into each other to hold the disc in the right position.

Step 9: Frame Connector

After getting the dimensions of the main housing and the tube of my bike where the new back light should be positioned I also created an stl-file of the new frame connector and printed it with a 3D-printer.

When I finished assembling the main housing and the frame connector I realized that I had to modify the frame connector a little to put it in the correct later on position. For thís modification I used a small file.