OMGLED

[TitanDiddly]

I'm modifying my mouse to replace the red LED with a blue one. I put the new blue one across the leads of the old red one, and it was very very dim. Probing with it on other areas of the boards allows for full brightness, but too much if I just use VCC and GND- overheats. The LED is 3.3v IIRC, not 5v. Through looking at traces and probing a bit, I've found that there's an inline transistor(Not sure on the term- small three-contact part, only two being used- straight through) that causes the dimness, I'm not sure if its dropping the voltage or limiting current. I'm assuming that this is done to keep the bright LED dim. However, my blue LED is way too dim with what they're giving to the red one normally.

Would it be safe to remove the transistor to allow the 5v LED to operate at capacity? I know the mouse changes the brightness kind of in an analog format (Take the mouse off the surface, and it out it back near it and it gets real bright in an attempt to pick up the signal from the surface) but even then it's in 'bright mode' you can barely tell that the blue LED is on. The blue LED seems to operate well when I manually bypass the transistor, not overheating or anything. Is it safe to perma-bypass it or remove it altogether?

Please advise.

 

[mrrman]

Is the transistor that you are talking about inline with any other components? I would say that if there was a resistor inline replace that with a lower rated one, less resistance more current.

 

[TitanDiddly]

Originally posted by: mrrman
Is the transistor that you are talking about inline with any other components? I would say that if there was a resistor inline replace that with a lower rated one, less resistance more current.

Nope, just the LED.

 

[RaynorWolfcastle]

A) your mouse may or may not work properly with a blue LED, it depends on the photoreceptor's response
B) Red LEDs generally have both a smaller forward voltage and require less current than the blue LEDs
C) The transistor you're thinking of removing is probably sourcing the current for the LED so that it isn't driven by the digital logic directly

I conclude that you don't really know what you're doing and should probably leave the mouse alone with the red LED

 

[TitanDiddly]

Originally posted by: RaynorWolfcastle
A) your mouse may or may not work properly with a blue LED, it depends on the photoreceptor's response
B) Red LEDs generally have both a smaller forward voltage and require less current than the blue LEDs
C) The transistor you're thinking of removing is probably sourcing the current for the LED so that it isn't driven by the digital logic directly

I conclude that you don't really know what you're doing and should probably leave the mouse alone with the red LED

A) I'm willing to give it a try
B) Good to know.
C)The current comes from the logic circuit. The transistor is a pass-through component- in and out, no other connections.

I'm pretty experienced with general electric stuff, but not with IC stuff.

 

[RaynorWolfcastle]

Originally posted by: PhasmatisNox
A) I'm willing to give it a try
B) Good to know.
C)The current comes from the logic circuit. The transistor is a pass-through component- in and out, no other connections.

I'm pretty experienced with general electric stuff, but not with IC stuff.

I'd have to see the circuit to be absolutely sure, but I 'm almost positive the transistor is sourcing current. You may not be seeing all the traces, there might be a trace on the other side of the PCB that goes to Vdd. Or it could be that the device is something other than a transistor, does it have 3 legs and looks like a "D" when you look at it from above?.

The other thing is that there is probably a resistor inline with the LED to limit the current, the value of the resistance does matter as it plays a part in how bright the LED will shine.

Either way, I don't think you should be toying with this any further unless you accept the fact that you may FUBAR the mouse permanently.

 

[myusername]

I am willing to bet that if mice would work with blue LED's, they would have been in production for the last year, given the lighting/casemod craze.

 

[TitanDiddly]

Originally posted by: RaynorWolfcastle

Originally posted by: PhasmatisNox
A) I'm willing to give it a try
B) Good to know.
C)The current comes from the logic circuit. The transistor is a pass-through component- in and out, no other connections.

I'm pretty experienced with general electric stuff, but not with IC stuff.

I'd have to see the circuit to be absolutely sure, but I 'm almost positive the transistor is sourcing current. You may not be seeing all the traces, there might be a trace on the other side of the PCB that goes to Vdd. Or it could be that the device is something other than a transistor, does it have 3 legs and looks like a "D" when you look at it from above?.

The other thing is that there is probably a resistor inline with the LED to limit the current, the value of the resistance does matter as it plays a part in how bright the LED will shine.

Either way, I don't think you should be toying with this any further unless you accept the fact that you may FUBAR the mouse permanently.

Heh, it's a $5 mouse - a backup for my main mouse actually, so I have no problem whatsoever with it dying.

myusername- People have been doing this for years. Google turns up a plethora of tutorials and guides, but none for my mouse specifically.

 

[DurocShark]

Originally posted by: myusername
I am willing to bet that if mice would work with blue LED's, they would have been in production for the last year, given the lighting/casemod craze.

I agree.

There are success stories about blue LED mods out there, but I wonder if the response curve is stunted with the blue output.

If it's only a $5 mouse, go for it. If it doesn't work toss the mouse.

 

[shilala]

Maybe get a blue led of the proper voltage rating?
I'd experiment with some different ones and see which works without frying too quickly. You can bypass the capacitance and see if that gets it, too.
You'll likely just toast the LED.

 

[TitanDiddly]

Originally posted by: DurocShark

Originally posted by: myusername
I am willing to bet that if mice would work with blue LED's, they would have been in production for the last year, given the lighting/casemod craze.

I agree.

There are success stories about blue LED mods out there, but I wonder if the response curve is stunted with the blue output.

If it's only a $5 mouse, go for it. If it doesn't work toss the mouse.

There's a couple:
http://www.spodesabode.com/content/article/irmod/2
http://guides.pimprig.com/modding/change_the_mx-700_led.php

 

[DurocShark]

Let me add one more thing.

I have the MS Starck mouse. It has lots of blue lights on it but the sensor LED is still red. Tell ya sometin'?

 

[dderidex]

Originally posted by: myusername
I am willing to bet that if mice would work with blue LED's, they would have been in production for the last year, given the lighting/casemod craze.

Yeah, the problem is that the sensor response curve peaks at the radiation wavelength closest to what we perceive as 'red'. Blue is pretty awful for responsiveness.

Chart

We see the wavelength of 620nm-660nm as 'red' (most mice use a 660nm LED). 'Blue' is a wavelength of 475nm. Although the typical "Blue" LED you pick up is not going to be quite that high. Another chart. Most LEDs that Radio Shack, et al, carries from the 'Blue' range are the "Ultra Blue" on that chart - 430nm.

Which, if you consult the Agilent chart above, you'll note will cut your mouse's responsiveness roughly in HALF.

EDIT TO ADD: Obviously, putting an Infrared LED in the mouse (850nm - 940nm) will make performance on the mouse just TANK. Course, if you are using a wireless mouse, I suppose performance isn't your thing, anyway, since their report rate is so abysmal, at any rate.

 

[Colt45]

pics of the ?transistor?

 

[TitanDiddly]

http://pics.bbzzdd.com/users/Phasmatis_nox/trans.jpg

 

[sharkeeper]

I have an HP travel mouse that has a blue LED for the optical engine source. Tracking is no different than a standard optical mouse.

Modification of a standard one to blue will likely lead to performance degradations. Blue LED's do require a higher operating voltage and do NOT produce as many photons with the same amount of drive power as well.

In any case YMWV. Happy modding!

EDIT:

After reading some of the responses from above I will add a few more things:

Reduction in output from the sensor has no bearing on mouse update rate. If the surface isn't picked up, the tracking will be lost. The mouse will feel like it's skipping. You can increase the gain of the op amps with the risk of more noise or find a more efficient emitter and/or use more drive power. Remember it's a CW device so it won't last long running at 125% WOT value!

 

[dderidex]

Originally posted by: Kvaerner Masa
Reduction in output from the sensor has no bearing on mouse update rate. If the surface isn't picked up, the tracking will be lost. The mouse will feel like it's skipping. You can increase the gain of the op amps with the risk of more noise or find a more efficient emitter and/or use more drive power. Remember it's a CW device so it won't last long running at 125% WOT value!

You missed the point of my comment. I didn't say it would.

I merely said that if you were using a wireless mouse (poor update rate), then the quality of your mousing experience is clearly not important to you, such that the reduction in response accuracy (using different wavelength LED) probably wouldn't matter to you.

They ARE two different things - I was simply implying that if you didn't care about one, you likely wouldn't care about the other, as they both affect performance adversely.

 

[sharkeeper]

Sorry but these are two different things.

Normal mice use (non FPS games) does not require high update rate.

Reducing sensitivity of the scanner has NO EFFECT on this parameter whatsoever. If your mousing surface is uniform and has decent reflectivity for the given wavelength and the scanner output stays higher than the noise floor, there will be absolutely NO DIFFERENCE in what the user feels, corded or not.

Now where the difference lies is being able to use the mouse on a variety of surfaces.

Basically it's like a person that sells overclocked chips and tests them in a 65F room and they pass in his machine but someone in San Juan with no A/C buys one and it fails in a 85F room.

 

[dderidex]

While the surface is relevant, what the "responsivity" of the sensor determines is HOW WELL IT READS MOVEMENT.

IE., the difference between a freshly cleaned ball mouse, and one gummed up with years of gunk on the wheels (think any college computer). THAT is a difference in responsiveness, and is what we are talking about here.

Not report rate - yes, absolutely that's a different factor.

But how 'smoothly' the mouse moves across the screen is not controlled by a single factor alone. What factors matter are:
- Report rate (nothing to do with sensor, more to do with chip and mouse->PC interface)
- Sensor resolution (obviously a big deal, but not really the question here)
- Sensor accuracy/responsiveness (this is effected by the LED used)

Yes, the LED used ALSO influences what kind of mousing surfaces are usable, but a sensor that is 50% as responsive because of an LED change is going to be 50% less accurate in reporting movement, and so will feel more 'sticky' (as above - very similar effect to a gummed-up ball mouse).