DIY XY scanner from PHR-803t lens positioner coils

[Achro]

I was messing around with some lens positioners from some PHR-803 sleds tonight. They have three degrees of freedom, in and out for focus, side to side, and tilt side to side for tracking. The coils are around 4 ohms, and the tilt axis drives pretty good with a couple tenths of a watt of audio from my amp, so I made a simple XY scanner out of two of them. I took the lens positioners off the sleds, soldered some wires to the tilt coil leads, removed the lenses, and glued some fold mirrors from some old sleds on where the lense were. I attached one positioner to the other so the mirrors were at a right angle to each other. Next I hooked one positioner up to the right channel, the other to the left channel.  Don't crank the amp too much or you will let the smoke out of the coil. Aim the laser about 45 degrees to the first mirror so it bounces and hits the second mirror. The frequency response is a bit slow because of the mass of the mirrors, but it looks pretty cool. You could also get some nice Lissajous figures with two sine waves from a function generator. I will try some lighter mirrors when I find some.

I would insert some pics, but the form isn't letting me in for some reason....

 

[potatorage]

Re: DIY XY scanner from PHR-803t lens positioner c

You can't upload pictures until you have a certain amount of posts (10 I think)

 

[Achro]

Re: DIY XY scanner from PHR-803t lens positioner c

I got 10 posts now, trying again...

 

[Achro]

Re: DIY XY scanner from PHR-803t lens positioner c

Here's a pic of the beam with some audio driving XY on my wall...

 

[LarryDFW]

Re: DIY XY scanner from PHR-803t lens positioner c

Achro;

It looks like resourceful use of parts you had in hand.

You can add a variable resistor (pot) in series with the coils to limit the power applied to them.

I would try a 100 Ohm pot and adjust the level with it.

Another forum member, "AP_Digital_light" has a link to building lightweight mirrors from plastic.

Here is the link to his video:

DIY Front Surface Mirror
http://www.metacafe.com/watch/1076186/diy_front_surface_mirror/

I prefer actual glass first surface mirrors for scanning, but they are harder to fabricate.

LarryDFW

 

[Achro]

Re: DIY XY scanner from PHR-803t lens positioner c

I will probably do something with opamps and add an agc/limiter and such to keep it from banging into the stops.

Thanks for the mirror link.

Jim

 

[Morgan]

Re: DIY XY scanner from PHR-803t lens positioner c

I really like this idea Achro. Being new to all this I thought those little coils looked useful when I pulled apart my first CD writer. I'm not sure they had quite the number of axis choices but now I KNOW this can be done I'll have a serious think...

Good stuff, thanks for posting it.

I'm hooking up an HDD to my keyboard at the minute while I wait for some parts for my, "Eye-phone", project.

I think I'm close to 10posts now so will try to attach what I've done so far. Don't know if anyone will be interested but hey.. I'm enjoying the challenge. Just a conventional x16 red, mounted on an Ericsson battery at the moment. Both work. Even at the same time if so desired. Looks like a wicked aerial! But I have plans.....

Thanks again,


M

 

[rog8811]

Re: DIY XY scanner from PHR-803t lens positioner c

I tried adding op amps to one I built but I always ended up with overshoot and bounce, I may revisit my setup and have another go some time.

Regards rog8811

 

[rog8811]

Re: DIY XY scanner from PHR-803t lens positioner c

I'm enjoying the challenge. Just a conventional x16 red, mounted on an Ericsson battery at the moment. Both work.

If you havn't already done so make your own thread with a bit more info in experiments and mod's...I think it is the first time I have seen this done so others may be interested.

Regards rog8811

 

[kendon]

Re: DIY XY scanner from PHR-803t lens positioner c

If you havn't already done so make your own thread with a bit more info in experiments and mod's...I think it is the first time I have seen this done so others may be interested.

+1

 

[ElektroFreak]

Re: DIY XY scanner from PHR-803t lens positioner c

I love some of the creative ideas that get posted here on LPF. This is just awesome!!

 

[Morgan]

Re: DIY XY scanner from PHR-803t lens positioner c

Re ericsson piggy back...

I'll put it in a thread. Thanks Rog.

M

(Not sure how to use the, "quote", function yet, (didn't work last time!))

 

[Achro]

Re: DIY XY scanner from PHR-803t lens positioner c

I tried adding op amps to one I built but I always ended up with overshoot and bounce, I may revisit my setup and have another go some time.

Regards rog8811

I was driving mine with an amplifier with a < 2 ohm output impedance. I suspect this helped the damping. In this manner, Any back emf generated in the coil would opposed strongly by the amplifier output. It is pretty easy to add a pnp/npn push-pull follower pair to boost the current capability of the opamp, or just use a high current amp like the l272.

-Achro

 

[tony70516]

Re: DIY XY scanner from PHR-803t lens positioner c

Achro;

It looks like resourceful use of parts you had in hand.

You can add a variable resistor (pot) in series with the coils to limit the power applied to them.

I would try a 100 Ohm pot and adjust the level with it.

Another forum member, "AP_Digital_light" has a link to building lightweight mirrors from plastic.

Here is the link to his video:

DIY Front Surface Mirror


http://www.metacafe.com/watch/1076186/diy_front_surface_mirror/

I prefer actual glass first surface mirrors for scanning, but they are harder to fabricate.

LarryDFW

No not even 100 ohms I have a laser spirograph pumping 12 volts all I need is a 25 ohm. Also don't buy front surface mirrors I used some regular round 1inch mirrors and they're fine

 

[Things]

Re: DIY XY scanner from PHR-803t lens positioner c

Never thought about using the positioner coils as a scanner. Creative idea!

 

[Achro]

Re: DIY XY scanner from PHR-803t lens positioner c

In answer to a PM I received on hooking up to the actuators:

I cut the flexible circuit off and soldered two small enameled wires on. I will post a pic in the thread. There are six leads going to the three sets of coils. One coil moves the lens from side to side (tracking), another coil tilts the mirror side to side, the third coil focuses the lens by moving it farther or closer to the DVD. The coil leads are brought out from the moving armature to the magnet / stator through the six support spring wires. I hooked the two wires up to the tilt axis (the center pair of leads) and hooked this to a small audio amp speaker output.