hand held projector :)

I will try to answer a few of the questions raised. The only real workshop tool used was my lathe for turning the plastic mirrors ( for card making,  ebay £1.50 loads left over for more projects), everything else could be covered with simple hand tools and a dremel.

The switch operates both motors, the first runs at constant speed for tunnel projection, the second one is variable to get infinate paterns, the controls were stripped out of an ipod dock/speaker/amplifier (ebay again  £2 ish)...I just removed all of the componants and wired to it as required.  On the subject of patterns, I have discovered that if I rotate the whole thing in my hand the motors change speed and hence paterns change without using the pot. I also cut down the the 4 battery holder, from the same ipod dock, to two batteries. I rejigged the connectors to get 1.5 volts with the two in parallel for longer life.
The motors were £2.50 each from ebay and came with the mounting clips.

When it comes to plans....well I had the radio spares box knocking around and checked to see if the batteries would fit, I had the cable gland and used a step drill to make it so that the greenie would fit, from there on it was just a case of making it up as I went along ...I cut a piece of thick cardboard and trial mounted the motors before fitting them to the base plate.

It is a very simple build, just needs time, care and around £10 ($20) to build, excluding laser pointer of course.


Regards rog8811

I have just put a movie of this up on metacafe on the following link.

http://www.metacafe.com/watch/763506/laser_projector_you_can_take_anywhere/


If you look at it there, could you rate it for me, it may earn me enough to buy some other laser related items

Regards rog8811

Nice video Rog, think I managed to rate it. Think I am gonna have to buy a Dremel...........

Nice video... I rated it as well

Thanx;
DDL

Rog8811 can you please answer

I am using a regular 3 volt motor, and purchased round mirrors from Michaels (the arts and crafts store ), its about a inch. Now when I am doing a trial setup, both the motors are running on 3volt, and tried different angle, but I am not getting the spiral.

How can I get the spiral?

1. Does both the motors have to run in different direction?
2. What angle both the mirros to be put?
3. I have a red laser which is less than 5MW does it make difference?
4. What is the characteristic of the pager motor, does it rotate and vibrate, causing the spiral?

Please answer me asap. If needed I will order pager motors online. I want to build this sooner...

Hi Sudra, lets see now......

1. Does both the motors have to run in different direction?

Click to expand...

Good question I think mine ran in the same direction but as they are opposed to each other they effectively run in opposite directions, reversing the polarity of one of the motors will do it no harm, I suggest you give it a try.

2. What angle both the mirros to be put?

Click to expand...

This is the most important one! The angle is VERY SLIGHT...When you set the motors up opposite each other check that when they are revolving, with the laser on, that the image from the first mirror falls inside the second mirror completely. If the angle is too great you will find that only a small part of the image is projected.

3. I have a red laser which is less than 5MW does it make difference?

Click to expand...

No problem at all, if you can see the spot from the laser when you point it at a wall it will project an image.

4. What is the characteristic of the pager motor, does it rotate and vibrate, causing the spiral?

Click to expand...

The only reason I used pager motors was that they were nice and small, they are just normal DC motors. To make them vibrate they would need an eccentric weight on the output shaft....not needed for your purpose.

I hope that has helped you If you are still having problems after trying the above post again, attach a photo of your set up it may help.

Regards rog8811

Thanks a lot for a quick reply.

I haven't stick the motors on board yet, but was trying holding one of them in my hand, which definitely gave me half images as you mentioned.

I have one more question, For a long time I didn't get the Spiral at all.

Do I have to paste the mirror Perpendicular to the motor "rod", or at a slight angle?

Do I have to place the mirror at slight angle on both the mirrors or one mirror?

What is the angle if you have calculated it, or any angle will do?

Can you send a picture of mirror attached to rod at angle. Just to get an idea?

Your setup is so cool, and it works great in the video .

Thanks,
sudra

If you look at the photo's on page 1 of this thread there is one showing the mirrors mounted on the motor shafts, they look almost straight....both mirrors need to just "wobble" slightly, it is all trial and error.

You will find it a lot easier to fix one motor down to a bench with sticky tape, grip your laser in a clothes peg and fix that down so that the beam falls on the mirror.

Again if you look at the photo's you will see the one with the motors mounted in the box. If you look carefully you will see that the laser is not aimed at the centre of the mirror.

Once you have that setup done run the fixed motor/mirror and hold the other one where the laser is reflected, this way you will get the position correct and you will soon be painting the walls with red rings

Regards rog8811

Oops... wrong thread

Hi Rog8811,

Thanks for your suggestion, I fixed one of the motor/mirror and played with the second one and I am getting better results ;D. earlier i was holding the motor in hand and was not getting the full image of the first mirror on the second one. But, I am not getting the spirograph as in you image 7. ITs so close spaced. Is it because of the speed of the motor? you are getting so close lines, or is it the angle on mirror and shaft?
mine shows a spirograph with a big circle in center and lines outside, but not so close.

IF you dont mind can you please attach a top view of both the motor and mirrors, I will get an idea of the angle to be set.

Also, in your video I saw that when you rotate the setup the shapes changes on the wall.

How is it possible. When the angle of laser, mirror everything is set, why the image should change?
Is it that when you rotate your setup, actually laser position is changing?
I am little confused. :-[

are you using front surface mirrors? if not, the extra circle might be the reflection from the mirror? just stick the mirrors on the motors, they will always be on a slight angle, it doesn't matter how big that angle is as long as it's not to big. he changes the patterns by varying the speed of each of the motors, using the potentiometers t adjust the voltage.
i hope that helps?

mine shows a spirograph with a big circle in center and lines outside, but not so close.

Click to expand...

Big circle in middle suggests to me that the first mirror is at too much of an angle, just expanding on what Things says if you were to try to get the mirrors on straight you would probaly have about the right angle.
I would need to dissassemble my projector to get the photo and to be honest I am not sure it would help as the angle is almost imperseptable

On the projector I built there is a pot to adjust the speed of 1 motor.
The reason the pattern changes in the movie is that as I rotate the projector in my hand the weight of the mirror on the motor changes direction of force on the motor bearings slightly and slows the motor down.

Regards rog8811

Thanks Rog8811 and Things,

You guys are awesome, your improvement tips are helping me a lot.

I am getting images like this.


But I am no where near to the image 7 posted by Rog8811.

Also I am using the 1 inch mirror, its not the plastic mirror, does it make any difference?

those patterns you showed are what this scanner is supposed to do, just simple spirographic patterns. any glass mirror will work better than a plastic mirror, but if they are too big, they may not spin fast enough, and the patterns would be much different