Easy USB Charger
This is an easy USB charger because you can get the electronic booster board already assembled. Just add the batteries, a couple of capacitors, the usb connector and nothing else.
Materials
The main component is the PTN04050, it takes the 2.4 volts from the batteries and raise it to 5 volts for the USB. You can get it from the Texas Instruments site here.
You will also need:
2 100uf capacitor
1 USB female connector
1 battery holder
Wires
You will also need:
2 100uf capacitor
1 USB female connector
1 battery holder
Wires
Assembly
The assembly is pretty easy, just follow the scheme. Try to not overheat the terminal of the PTN04050 and be careful with the polarity of the USB connector.
Finish
Find a nice case for your charger, an Altoids tin would be great, but I can't find one of that in my country so I will keep look for a case.
For testing the device at first I used my USB tester and then I tried it with my mp3 player, but there shouldn't be any problem if I were careful with the assembly.
For testing the device at first I used my USB tester and then I tried it with my mp3 player, but there shouldn't be any problem if I were careful with the assembly.