I am planning to make a portable charger that works with batteries, cables and a USB charger. I chose this because sometimes you don't have a place where to charge and your friend doesn't want to lend you a charger so in that case it will work. Another reason I used this was because I wanted to work with cables and a solder, and how I knew this will be challenging I chose is because at the end I will learn new skills and it will eventually pay of.
Step 1: What You Will Need
1: 1 new 9 volts batteries
2: 1 used 9 volt battery
3: An Altoids box
4: A switch
5: Some wires
6: Silicon gun/glue
7: Portable charger
Step 2: Take the Battery Cap
This will be a step you can't miss because the cap of the battery will be one of the main sources because it will connect to the battery and to the USB port. What will happen if you miss this step is that you won't be able to achieve the portable charger.
Step 3: Use a Solder to Melt Two Metals for Them to Attach and Use Sylicon Glue
The solder will work for the metals to attach when you melt the metals and they attach you use silicon glue because maybe they can detach and that will not be good. What you have to attach are the 2 cables to the battery cap.
Step 4: Use the Solder Again to Connect It to the Switch and the USB
In this step what you need to do is use the solder again and you will have to connect the other end of the cable to the USB and to the switch so that both can work.
Step 5: Use a Exacto Knife
The exacto knife is used to cut some holes and you need to cut 2 holes on the altoids box one is for the USB to fit and the other one is for the swith to fit.
Step 6: Final Step Oraganize Everything
You can organize everything as you want just that you need to have the USB and the switch sticking out.