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CRT Yoke to the Rescue

A project log for 3D Printable 2-axis MEMS Mirror

A home buildable 2D mirror for controlling light deflection.

zach-baldwinZach Baldwin 06/14/2021 at 00:030 Comments

A friend of mine was getting rid of a projection TV and asked if I could come over to help dismantle it to get it out of his basement. Excited to tear down his TV (and get some lenses), I headed over and after about an hour, we had a pile of electronics and a pile of wood and plastic.  I got to take the electronics home and while I was unloading everything, I realized that the deflection yokes from the CRTs were designed for the sort of task I was trying to solve.

Don't these look like Podracer engines?

With the yoke in hand, I did some quick 3D modeling to create a 30mm diameter 2-axis galvanometer to fit in the center. To make sure the gimbal had a tight fit inside the yoke, the outside was wrapped with about one and a half turns of masking tape.

In the small hole in the center, I put a small nail to give the yoke something to act on. Connecting one axis of the yoke to the bench supply, I was able to get about 1-2 degrees of deflection out of the gimbal. Despite operating at around 2-3 amps, the coils did not get terribly warm, even after a few minutes of adjusting the current. This new setup seems to have the heat problem solved, so now on to getting more deflection out of the gimbal.

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