Hackster loves technology, but we recognize that e-waste poses a serious threat to the environment and sustainability. We’re huge fans of projects which recycle or upcycle obsolete electronics, otherwise they would end up on landfills. Giving old electronics a second life allows you to avoid buying a brand new device and also prevents it from being thrown away. If this sounds appealing to you, and you are able to access old hard drives then JGJMatt’s tutorial explains how you can turn them into planar speakers drivers.
All speakers drivers transform electrical signals to mechanical energy, which is usually vibrations inside a cone. The majority of speakers achieve this by sending the amplified audio through an electromagnet which then attracts a magnet attached to the speaker cone. Planar speakers are one of the other types. Planar speakers have permanent magnets either side of membranes with embedded coils. The membrane vibrates as the audio signal is amplified and passes through the coil. This vibration creates sound just like in any other speaker.
Hard disk drives happen to have powerful permanent magnets. You can also use other components from hard drives in various projects. JGJMatt says that you’ll need to use a Dremel with a diamond-cutting wheel to cut magnets in half. The poles of hard drive magnets are at the opposite ends. This is required to create a uniform magnetic plane.
JGJMatt has designed 3D-printable magnet holders. The driver needs to place a membrane with a coil in between the two magnet planes. JGJMatt has a number of different fabrication methods that you can use depending on what tools you already have. The easiest is a thin 3D printed membrane with a spool structure, where you can wrap the copper wire. A membrane can be made using UV-etching, similar to the techniques used for custom PCBs. If you own a 3D resin printer, you can use a similar technique to cure the resin that serves as the mask.
JGJMatt has uploaded a clip that demonstrates the 3D printed membrane. It sounds decent. The sound quality is not high-end, but the project would make a great weekend project.