A VIDEO DEMO OF THE MOUSE WORKING:
http://www.youtube.com/watch?v=luZazXOj9Mc

You will hear a pen drawing, the newspaper, any fabric pattern, any real or printed grid etc.
Just move the modified mouse over it.
It may prove usefull for blind people.

Anything but solid colors will sound.
Im working on makeing it convert uniformly colored surfaces to a musical note that tells the person how dark or bright is such surface.
We could even get a tone for the Hue and another for the brighness. Each tone with different quality. This would be cool.
But we need 3 more especial sensors with red green and blue filters, and more complex circuitry...

For now it converts the changes of light and dark under the sensor in high and low values of a wave that one may hear.
So you move it over a surface and hear its texture.

Shopping List:

* 1 x Optical mouse that may work or not, as long as the red led works.

* 1 x phototransitor (the most common ones, that look like transparent leds)

* Thin colored cables from inside the mouse usb cable, or from inside a parallel printer cable.

* 1 x BC337 or similar (small, 3pins, very common transistor)

* 1 x 741 (8pins, very common Op amplifier, only 5/8 pins are used)

* 2 x 500 Kohms Presets

* 1 x 1 Kohm Preset (the one marked as PST3 in the circuit drawing)

* 2 x 9 V Batteries

* some sinthetic paint (I used black, but after thinking it, white may give more reflection inside the sensor chamber, will understand in step 4)

Some mono audio cable, the longer the cable, the longer he reech.

1 mono audio plug of the kind that may be more convenient for you

1 x printable circuit board, or a prototype circuit board if you dont want to have fun making the board your self.

Some ferric perchloride (eats the copper on the board leaving only the tracks we draw)
You wont need this if you use a prototype board which has already drawn the tracks.

2 x Battery plugs, like double buttons, like in the picture. May be purchased or taken from old toys.

Tools:

Pliers
Wire cutters
Some cable stripping tool
Soldering iron &tin
Hot glue gun
Multimeter
Protoboard
Screwdrivers
A drill and a 5 mm drill bit. (or the diameter of the fototransistor you have)

Optional 1mm drill bit.
Optional drill stand.
Optional Permanent marker, all this if you plan to homemake the amp board.

A VIDEO DEMO OF THE MOUSE WORKING:
http://www.youtube.com/watch?v=luZazXOj9Mc

Step 1: Taking Appart the Mouse and Drilling Its Chip.

Just take the screws from the bottom of the mouse and take the upper cover.
You may need to take some more screws to get the board with the camera chip and red led.

Take out the usb/ps2 cable and strip it to get coloured thin cables.

Open the black cover under the chip, in the hole of the board. Making preasure with a knife in the edge of the cover to pop it out.

With the drill make a 5 mm hole in the microchip, aligned with the place where the small hole of the cover you just took out would be.

It may be better if you have a drill stand.

Put back the cover of the chip and make sure that the hole in the chip is in the middle of the small hole of the chip cover.

Step 2: Give DC to the Led

We should cut the copper tracks of + and - of the led in the original mouse board.
Then weld thin cables to the led pins to give them DC current from the homemade board of step 7.
10 cm cables are ok. Weld the + of the led to PST3. As you see it in the circuit drawing.

PST3 should be around 300 Ohms, dont make it much less than this or you will burn out the led and will have to replace it or start again on another mouse.
You could really just use a 330 Ohms resistor instead of the PST3.
I put it to make sure to get the most brightness from the led.

Step 3: Prepare the Phototransistor and Hotglue It to the Mouse Chip.

Now weld thin cables to both pins of the phototransistor.
15 cm cables may be enough.
Cut the excess pins of the sensor.

Place the sensor inside the hole in the mouse chip and hotglue it around.
Keep holding it with your hand in vertical position, aligned with the thin hole in the chip cover.
Dont let it go until the hot glue is cool.

Step 4: Creating the Blind Sensor Chamber.

The problem now is that the sensor and the hot glue are transparent.
Light gets to the sensor from bihind it.
To avoid this we paint the hotglued sensor, 2 or 3 times ensuring to cover all the transparent surface, but avoiding to paint the lens or led.

Now we are ready for the first test of the system.

Plug the possitive pin of the phototransistor to the possitive pin of a 9V battery.

Pin a 500K preset to the negative pin of the photo.

Pin the other end of the preset to the positive audio out.

Plug the negative of the battery to the negative audio out.

Reasamble the mouse as it is now.

Plug the audio out to some AMPLIFIED speaker.

For now the signal may not have enough amplitude to be heared with headphones or sthing.

Step 5: Protoboarding the Amplification.

Just make the circuit in the drawing on a protoboard and make sure everything works fine before making a homemade amp board.

Step 6:

Now the more crafty part.

We need to cut the original mouse board so that we room for the homemade board.

And then just make the board and weld all the thin cables from the sensor and led to the board.

If you dont know how, get help or google, its not very hard.

Just draw the tracks with a permanent marker on the board, submerge it in percloride for about 15 minutes, untill all the copper is gone.

Then drill the holes for the chip pins, the input cables of the sensor, the +9v, 0v and -9v.

Drill the holes for the cables of the audio output.

Weld everything in its place.

Glue the cables together, the presets and the two boards in their place.

Step 7:

The last step would be to weld the external audio and batery cables to the thin internal cables.
You may need to cut bigger the hole in the mouse case for the three cables to pass through.
When you can close the upper cover it´s done.

weld the + and - of the audio output to audio jack, or rca

Now hotglue the two batteries to the top of the top cover of the mouse.

Plug the batteries and the audio jack and play.

You can use 4 or 6 CR2032 batteries, button shaped. much smaller, that may fit inside the mouse.

And if you install a small speaker to the mouse you have a fully portable device :)

You can create images like the one in this picture, trying to create different wave shapes as a normal sinth would.

I will update this instructable if I get the 40106 oscilator working to make a sound depending on the brightness of a surface.

If somebody makes it Id like to see pics!