In this instructable, we will be reusing a defective wall adaptor as a USB powered laptop charger.
This example is intended for macbook air users but this charger can be altered to be compatible with other laptops.
Youtube Version of this project is available here:
Step 1: Parts
Components used in this project:
Step up Voltage regulator
Small voltmeter with display
Step 2: Disassemble
Using this video as a guide, disassemble the macbook charger using pliers.
Since this is a defective wall adaptor, only the outer shell and the charging cable was utilized for this project.
Additionally, the silver ground pin should also be removed for USB cable access.
In order to monitor the voltage display, the power pins have to be removed using pliers.
Step 3: Connect
Output: Connect the ground wire from the magsafe cable to the - Out connector.
Output: Connect the positive wire from the magsafe cable to the + Out connector.
Output: Connect the ground wire from the voltmeter to the - Out connector.
Output: Combine the white and red wires of the voltmeter together and connect it to the + Out connector.
Remove the micro usb from the usb power cable and thread it through the ground pin hole.
Input: Connect the ground wire from the usb cable to the - Vin connector.
Input: Connect the positive wire from the usb cable to the + Vin connector.
Solder everything together and make sure that all the wires are secured.
Step 4: Assemble
Use double sided tape to secure the voltage regulator inside the enclosure.
The input side of the voltage regulator should face the top of the charger where the usb cable is connected.
The output side of the voltage regulator should face the bottom of the charger where the magsafe cable is connected.
The voltmeter should be mounted at the corner of the charger so it can be monitored visually.
Once all the pieces are in place, use hot glue gun to glue all the components to the enclosure.
Before closing the enclosure, drill a hole next to the potentiometer so that the voltage can be changed.
Step 5: Done
After sealing the charger shut, adjust the potentiometer to match your laptop's charging requirements. (macbook air charges at 15v)