Thereâ€™s something to be said about the falling costs of printed circuit boards over the last decade. Itâ€™s opened up the world of PCB art, yes, but itâ€™s also allowed for some experimentation with laying down fine copper wires inside a laminate of fiberglass and epoxy. We can design our own capacitive touch sensors. If youâ€™re really clever, you can put coils inside four-layer PCBs. If youâ€™re exceptionally clever, you can add a few magnets and build a brushless motor out of a PCB.
We first saw [Carl]â€™s PCB motor at the beginning of the year, but since then weâ€™ve started the Hackaday Prize, [Carl] entered this project in the Prize, and this project already made it to the final round. Itâ€™s really that awesome. Since the last update, [Carl] has been working on improving the efficiency and cost of this tiny PCB motor. Part of this comes from new magnets. Instead of a quartet of round magnets, [Carl] found some magnets that divide theÂ rotor into four equal pieces. This gives the rotor a more uniform magnetic field across its entire area, and hopefully more power.
The first version of this 3D printed PCB motor used press-fit bushings and a metallic shaft. While this worked, an extra piece of metal will just drive up the cost of the completed motor. [Carl] has redesigned the shaft of the rotor to get rid of the metallic axle and replace it with a cleverly designed, 3D printed axle. Thatâ€™s some very nice 3D printing going on here, and something that will make this motor very, very cheap.
Right now, [Carl] has a motor that can be made at any board house that can do four-layer PCBs, and heâ€™s got a rotor that can be easily made with injection molding. The next step is closed-loop controlÂ of this motor. This is a challenge because the back-EMF generated by four layers of windings is a little weak. This could also be accomplished with a hall sensor, but for now, [Carl] has a working PCB motor. Thereâ€™s really only one thing to do now â€” get the power output up so we can have real quadcopter badges without mucking around with tiny brushed motors.
[Carl] has put up a few videos describing how his PCB motor works; you can check those out below.