There are many designs for iPhone chargers out there and many are confusing or use parts that are hard to find. My design uses parts that are easy to find, is tested works with all iPhones and iPods (as of this posting), and just works. It is a fun and useful project. I made one a few years ago and put a video on YouTube. I weekly get many questions about making one. So here you go and i hope you enjoy it.
Step 1: Parts List:
- 1 - SPST Switch (I used a toggle switch)
- 1 - LED for "ON" indicator red or green (Radio Shack sells LED's with resistor "350 ohm" you can mount. That's what I used.)
- 1 - 350 ohm Resistor
- 1 - 7805 Voltage Regulator
- 1 - 22uF Capacitor
- 1 - 10nF Capacitor (code 103)
- 2 - 33K Resistors
- 2 - 22K Resistors (Other values can be used, read step 2)
- 1 - Female USB Connector (I got mine at a dollar store)
- 1 - 9v Connector
- 1 - 9v Battery
- Electrical Tape
- Soldering Iron
- Small piece of perfboard
- Altoids Tin
- Dremel Tool with cutting attachment or tin snips to cut the tin
- Drill for switch and LED hole
- Hot Glue
- Paint if you want
You can go here for a good tutorial on soldering.
For most of the parts you can use techno scrap and recycle old broken electronics or just buy them.
I wanted to use parts that are easy to find and inexpensive so everything can be bought at Radio Shack or if your don't mind on-line shopping I like http://www.taydaelectronics.com/servlet/StoreFront because it's cheep!
I hope you enjoy the project.
Warning: Just a fair warning that there is a small chance that something can go wrong and you can end up frying your really expensive iPod. Be careful.
Step 2: How Does It Work?
All USB plugs run at 5v so need a way to make a portable 5v charging device. There are a few ways to do this. The way we are going to do it is to use a 9v battery and reduce its voltage to 5v with a 7805 voltage regulator. First, i like toggle switches and LEDs, the switch is placed first near the battery to ensure it's not running when not on. Then the LED (on indicator) and resistor before the regulator, but on ether side of the regulator a capacitor is placed to smooth out the current a bit.
For most USB charged devices this would be enough. Just attach the red and black wires from the USB and it should work, but Apples iDevices have a feature that tries to stop people like us from making our own charger or using most other non-Apple chargers. The iPhone or iPod Touch needs to "see" a 2v charge in each of the 2 USB data lines as a, "OK, this charger must be from Apple so it's time to start charging from the 5v." This is why you need the extra resistors to make a voltage divider to make the 2v because 22K / (22K+ 33K) * 5.0V = 2.0V. When I made mine I used the 22K and 33K values but you can also use 2 50K and 2 75K or 2 100K and 2 150K to also reach 2v. Let me know in the comments if those other values actually work, I think they will.
I have tested this charger with a few iDevices including an iPhone 4. For iDevises the charger will work until the 9v battery gets down to around 6v or 5v. Then you will get a message saying "Your iPhone does not recognize this charger." You may not get a whole charge out of a battery, so it is great to keep for emergencies. This charger can charge much more than iDecives. I have used it with other MP3 players, cell phones, cameras, and video cameras. Really anything that can be charged with a USB. That really was helpful when my kids were being cute and I wanted to video tape them but the recorder was dead. Just plug it in, carry it along, and catch those precious moments on video.
Step 3: Putting It Together
- Use your Tin to lay it out your pattern to make sure your wires are the right length.
- Solder the red (positive) wire from the battery connector to one pin of the switch and from the other pin to the perfboard.
- Solder the black (negative) wire from the battery connector to the perfboard also. So now you can have a positive and a negative side.
- Attach wires to your LED long enough to put it where you want it. Solder the positive LED lead to the board with the positive wire.
- The LED negative side has a small flat spot on the side of the plastic. Attach that wire to the 350 ohn resister.
- Then the other side of the resistor to the negative side of the board.
- Place the 22uF Cap in the board. The side with the line on it is the negative side and goes to the negative wire. The other is positive and attaches to that wire
- Now comes the 7805. If you look at the front of the chip, the left pin is attached to the positive wire in your board (which is from the 9v battery), the middle pin is ground and is attached to the black (negative) wire, and the right pin is 5v out which will be the positive source for the rest of the circuit. (see diagram for pinout) You can see in the pictures i used a heat sink on the 7805 but that is not necessarily.
- Then add the little 10nF cap to the negative (ground) and the positive 5v.
- Now comes the voltage divider. You need 2 33K resistors connected to the positive 5v and each of those are connected to a 22K resister which is then connected to ground (negative, black).
- Almost done
- Now the Female USB. If you get one with wires still on it will be a little eaysier. If not just attach your own wires. The red wire needs 5v and the black needs to go to ground. The green and white wires each need 2v and are attached between the 33K and 22K resistors.
- Plug in the battery, the iPhone/device, and turn it on :-)
Step 4: Prep the Tin
Then just install all the circuit guts, use a little hot glue to hold down the USB and you're good to go.
Step 5: More Information
My YouTube Chanel for more techie videos :-)
The Mysteries of Apple Device Charging. With a Cool Video. Thanks Lady Ada.
If you have questions you can leave them in the comments and i'll do my best to answer them.