⬆️ | Introduction | Parts Required | Assembly
The Bluetooth stereo from eWaste is a singularly low cost electronics project. It uses an old iMac aluminum frame and foot, a solar panel, recycled car speakers, and a combination 18650 battery charger/bluetooth speaker amplifier. The 18650 rechargeable cells you can pull from old laptop batteries!
- 20W 12 Volt solar panel (10W may also work)
- 12V -> 5V USB voltage converter
- PAM8403 or XH-A153 battery charger + Bluetooth speaker amplifier
- 18650 lithium ion battery (new or from ewaste)
- iMac 27" aluminum foot (from eWaste)
- high fidelity speakers (from luxury cars in the salvage yard)
Two ways of attaching the solar panel securely to the iMac frame: short screws into a thin piece of hardwood from the back, or (more securely, less chance of damaging the cells) into a thicker piece of hardwood using long screws drilled into either side of the solar panel. The battery charger + Bluetooth speaker amplifier has holes in the circuit board in either end that can attach with small bolts through corresponding holes in the iMac frame, or via screws into the back of the wood.
To charge the board, solder the 12-5V USB voltage converter to the solar panel as in the solar briefcase project. Place a recycled 18650 lithium ion rechargeable battery in the battery slot, attach a connection cable: USB-A from the voltage converter to the mini USB input of the battery charger. The 12V to 5V USB voltage converter LED glows blue when it has a voltage, and the battery charger shows red while charging, green when full.
Attach the ewaste speakers to the appropriate wires supplied with the board. The best kind by way of frequency response are a combination woofer-tweeter, often found in the automobile scrapyard in discarded luxury cars, however any speakers should work. Pair your streaming media device with the bluetooth device to hear it through the speakers. The yellow LED indicates pairing has occurred. The 18650 battery holds 2-3h of charge, so after dark, the stereo will continue for hours! Make sure to wrap any exposed components in electrical tape, so they don't ground on the aluminum frame.
