Laser lumia illuminated obelisk

[dar303]

What diameter is your lumia disc, about 12 centimeters?

[robvdv]

15cm. To get a nice pattern rotate as slowly as possible and shine a 1 or 2 cm line as close to the outside of the wheel as possible. If you shine it near the middle the rotation of the wheel becomes apparent in the pattern.

[dar303]

Thanks!
I have a couple of 1000:1 gear motors that I will try: http://www.pololu.com/catalog/product/1596

[robvdv]

I'd slow it down further if you can, particularly with a large lumia wheel. Wheel rotation speed makes a big difference to how good the projection looks. There are lots of videos on youtube that illustrate this.

This guy in particular does some amazing stuff: http://www.youtube.com/watch?v=KwgmHS0O9Vo

[dar303]

The motor have a minimum speed of about 1 RPM at 0.6 V, I will try with a simple constant current generator or a 555 PWM circuit and see what speed I can get under load.
Thanks for the link, that oil trick was cool!

[robvdv]

Watch out for burning out your motor by dropping it below stall speed. I spent a lot of time and effort trying to control the speed of the motor electronically. In retrospect I should have just added a 200:1 gearbox and been done with it.

[dar303]

Since it has a 1000:1 gearbox already I might just set it at decently slow speed with a lm317 voltage regulator and then use a rubber band and a simple belt drive reduction with a rubber band if slower speed is required. I'll be sure to post pics when I get there, thanks for the tips!

[Galvonaut]

I keep finding stuff on this forum that simply melts my mind more and more! I'm going to end up a lasery wreck!

Amazing work robvdv

[skot]

I know this is digging up something old, but this looks great. Such relative simplicity for a stunning effect.
Nice work.

[robvdv]

Thanks :-)

I'm playing with a new design that uses a P73 and a M140. I was hoping to get a "flame" that fades from blue through magenta to red. Struggling to get the blending right. Seems the two "flames" split into two overlaid patterns and don't blend as expected.