People use smartphone a lot these days , smartphone batteries are not powerful enough to keep up. So pluging it again and again when the battery drains out is so pain. So i made a portable charger (not exactlly it is still a rough circuit).
Step 1: Parts
1.A broken car charger for smartphone.
2.9 Volt battery
3.Some Wires with alligator clips
Step 2: Process
Take the car charger and find the positive and negative terminal.Next, Take the wires and solder it with the car charger and the battery.And smartphone begins to charge.The photos shown are not the complete idea i had but it shows the rough idea.