I often find myself with my iPod or iPad at about 10% charge, but without a way to charge it. I recently discovered that you can buy keychain chargers, and that immediately got me thinking about how I could make one myself. At first I wanted to make a mini lightning cable, but soon found out that the lightning cable contains a small chip beneath the plug that makes it impossible to modify.
Step 1: Supplies
- A 30 pin (older generation iPhone, iPod, or iPad) cable: I used an old torn cable that I found lying on the road. If you can't find an old cable I recommend buying a cheap third party cable, which you should be able to get for less than $5. My cable's USB end was a bit bent so I had to use a different USB cable. Altogether I used an old 30 pin cable and the USB end of an old Nokia charger
- 2-3 mini packs of Sugru
- Soldering iron (fine tipped) and solder
- Needle-nosed pliers
- Dremel rotary tool and cutting disc: This is what I used to cut open the cables. Other tools might work just as well.
- Craft knife e.g. Exacto knife
- Third hand
- Key ring and hook
- Metal reinforcement rings
Step 2: Baring the Wires
The first step in making the charger is to strip away as much as possible from each side of the cable. My 30 pin cable had a messed up USB plug, so I took the USB of an old Nokia cable.
I used a dremel with a plastic cutting disc to cut open the plastic encasing, then used a knife and some scissors to strip the cable.
Once you have the casings and rubber tubing removed you'll notice that the wires are wrapped in a tight metal mesh. Strip it away too. You should end up with a bare plug as shown above (I didn't take a picture of the bare 30 pin cable, but it's the same deal).
You should now have two bare plugs with four colored cables each: black, green, white, and red.
Step 3: Soldering
This is where good soldering skills will come in handy. Match up each wire with its corresponding color on the other plug, and start soldering them together. You can strip each wire down to the bottom, and cut off the wires so that they're around 1-1.5cm long. If you think you can still solder them if they're even shorter, go ahead.
Step 4: Test the Cable
Once you've got them all together, check that it actually charges and syncs your device. If it doesn't, you may have mixed up two of the wires or one may have gotten disconnected. In order to charge only the red and black wires are needed, and to sync you need all four.
Step 5: Sugru
Before I made this, I had the idea of a perfectly symmetrical form with straight sides and flat surfaces. It turned out that getting things straight and symmetrical with Sugru is practically impossible. You might be more satisfied with the result if you make it free-form and as shapeless as possible.
You're going to need at least two packets of Sugru for this. Start off by taking small bits of Sugru and covering the bare soldered wires. Make sure that none of the cables touch each other (if they do, bend them outward slightly, then put some Sugru between them). Once all the wires are wrapped in Sugru, start covering the rest, as shown above. If you want to flatten the Sugru without leaving fingerprints, use some baking paper and a flat surface, such as a piece of wood.
Step 6: Cap
This is the tricky bit, and I think I could have found some better solutions if I had really tried. I used a part of the 30 pin adapter that fit tightly onto the plug, using that to start making the cap. The problem with my cap is that it doesn't hold on to the plug very well, so I have to continuously add tape to the inner wall to make it a tighter fit. If I had not broken apart the 30 pin in an attempt to salvage the lightning plug I could have used the entire adapter. Another alternative would have been to make the cap on the USB side of the cable, using a simple USB socket. The reason why I decided against that was because I wanted to keep it key shaped.
For the keychain hole I used two metal reinforcement rings, glueing one on either side of the hole I made in the top of the cap.
Step 7: Done
So that's my version of the keychain iPhone cable. Please post any questions, suggestions, or pictures of your own version below.