As my kids were quite excited with my BuffaloAmp project, i organised a speaker building project for my kids workshop groups. This project has evolved a bit over time, the current version uses a laser cut tabbed box with 2x 3W 4ohm speakers.
For details on the circuit, see the original larger size. First i downsized it to 2W 8Ω drivers, and left out the DC-DC booster, powering the amp straight from a Lithium cell, nominal voltage 3.7V. At that voltage, the amp would only deliver 1W per channel, so these smaller speakers can’t get damaged. I used the same Lithium battery charger but did not take out the charge status LEDs; we just made holes in the side of the speaker box to be able to connect the micro USB directly to the charger PCB, and the red/green light is visible through the hole.
The latest edition (2017) is a laser cut tabbed box with 3W 4Ω speakers as in below picture.
To make this project with kids, i usually split it up in 3 sessions:
- understanding the electronic parts and connections
- putting the wooden box together
- installing the components in the box
So this speaker box just needs to plug into a music source, any phone or mp3player with a headphone connection (3.5mm jack). The battery lasts for over 10 hours, and can be recharged with a standard micro USB connector, just like a powerbank.
I prepared the box panels for the kids, including gluing the triangular supports to the side panels. The got 6 panels, and together we drilled the holes for the screws with a cordless hand drill. The holes for the speakers were a bit more challenging, i borrowed a circular drill bit from a friend. Then we put the components into place with hot glue.
And the kids were very creative to paint their boxes!
The most recent batch of box panels were made with a laser cutter, and i also made a simplified version with 3x AAA batteries (non-rechargeable).
I explain the schematics with a puzzle as below, and then i ask the kids to draw their own version on a card to stick on the back of the speaker, as above.