Here is an interesting problem.

[GonzoEngineer]

I went nuts a few days ago trying to find a problem with my trackball.

It started acting up and doing weird thinks, or it didn't work at all!

I took it apart, cleaned it...found nothing wrong.

The next morning, it worked fine. But that night it started acting up again.

Turns out that the problem was my new Halogen desk lamp!

Moved the lamp to the other side of the desk and all was well!

Just thought you might want to store this tidbit in the back of your minds in case you ever come across a similar problem!

 

[glutnix_neo]

hmmm, that's interesting . It could be caused by the EMI emitted by the desk lamp.

 

[GonzoEngineer]

hmmm, that's interesting . It could be caused by the EMI emitted by the desk lamp.

Actually, it was the light itself, leaking through the opaque plastic case.

If I shine the lamp on it it goes nuts!

 

[whiz115]

the IR receivers getting interference from the light of you desk lamp?
weird...... unless your mouse has UV receivers which again weird.

 

[Rolf]

Very Interesting ...........

I went nuts a few days ago trying to find a problem with my trackball.

It started acting up and doing weird thinks, or it didn't work at all!

I took it apart, cleaned it...found nothing wrong.

The next morning, it worked fine. But that night it started acting up again.

Turns out that the problem was my new Halogen desk lamp!

Moved the lamp to the other side of the desk and all was well!

Just thought you might want to store this tidbit in the back of your minds in case you ever come across a similar problem!

My old cordless Logitech shows no similar problems, even when held a few inches from my 20w halogen lamp. Do not know the model # of mine, the label is gone.

Those trackballs are great!

Thanks for the heads up.

 

[GonzoEngineer]

My old cordless Logitech shows no similar problems, even when held a few inches from my 20w halogen lamp. Do not know the model # of mine, the label is gone.

Those trackballs are great!

Thanks for the heads up.

If I put the lamp about 15 inches above the trackball it goes nuts! I put my left hand over the trackball to shade it....and it works perfectly!

This isn't an EMI problem.....its a photon problem!

Could it be that Halogen lights produce more infrared?

I think my next step is to take the top cover off the trackball and paint the inside with black paint...just to see if it works!

 

[Hayato]

Yes.
Halogen lamps procuces much heat therefore much IR.

Or its light intensity could, I dunno, attrackt some ghosts.

 

[GonzoEngineer]

Yes.
Halogen lamps procuces much heat therefore much IR.

Or its light intensity could, I dunno, attrackt some ghosts.

I am an Engineer...we don't believe in ghosts! There is always an explanation!

 

[Rolf]

{snip}
I think my next step is to take the top cover off the trackball and paint the inside with black paint...just to see if it works!

That sounds like a good idea, hold it up to the light first and get some feeling for how much light is coming through. Or maybe just a strip of black electrical tape in the correct place.

Are you able to locate the spot of the interference by shading it with your finger? If so maybe you could to put the tape on the outside temporarily.

 

[Hayato]

You have to be cautious with that. Black is not opaque to IR

 

[GonzoEngineer]

This is an old trackball....the top cover is about 6x4 inches. It is made of injection moulded plastic with a light grey color but opaque still.

I actually took a black permanent marker (Sharpie!) and painted the inside of the top cover and it worked!

So what was the problem.....Infrared?

 

[Hayato]

Yes, I believe so. I did not consider the wall thickness.

Infrared or some light infiltration. The trackball position sensors works with IR, isn't it?

 

[GonzoEngineer]

Yes, I believe so. I did not consider the wall thickness.

Infrared or some light infiltration. The trackball position sensors works with IR, isn't it?

Yes they are...obviously the lamp is putting out IR, (probably at 60Hz?), and it interfered with the optical sensors on the board.

Learn something new everyday.......

 

[Hayato]

But it's strange to know that isn't any bandpass filters in the mouse tho prevent this kind of interference.

 

[GonzoEngineer]

But it's strange to know that isn't any bandpass filters in the mouse tho prevent this kind of interference.

It is an old trackball............I bought it many years before Halogen desk laps came around.

 

[Rolf]

IR test............

You have to be cautious with that. Black is not opaque to IR

In my experience black (tape) might not be 100% opaque to IR but it is a fantastic attenuator.
To prove my point, you can make this simple test for yourself. Take a piece of black electrical tape and put it over the IR emitter of a TV remote. Now see how close you have to approach the TV before it works. In my case I have to be within 16"! Go and figure.

Next I am going to take a few IR pictures with my camera without taking the lens cap off! (just kidding!)

 

[Hayato]

In my experience black (tape) might not be 100% opaque to IR but it is a fantastic attenuator.
To prove my point, you can make this simple test for yourself. Take a piece of black electrical tape and put it over the IR emitter of a TV remote. Now see how close you have to approach the TV before it works. In my case I have to be within 16"! Go and figure.

Next I am going to take a few IR pictures with my camera without taking the lens cap off! (just kidding!)

Nice test!

But we have to consider the thickness, as well. I believe that a layer of black electrical tape is about 10x thicker than a layer of black ink.

 

[whiz115]

change your bulb with one of a higher quality that has the needed UV/IR coatings!! don't change or paint your mouse...

i believe you're still using your desk light with the bulb that came from the factory...

[edit]

These halogen bulbs without coating could be useful for PCB deveping.

 

[kchriste]

It would be interesting to see if one of Gonzo's hands is more tanned than the other!

 

[GonzoEngineer]

Well, the marker worked, but not perfectly.....I just moved the damn lamp!

Will look into another bulb when this one burns out.

I could get another trackball, but my hand likes this one. The ball is also the same size as a pool ball.....I replaced it a long time ago with an eight ball and it looks pretty cool!