how much volt does an optical mouse LED use?

[700nm]

I want to change the LED of my mouse to IR and possibly re-use the red LED that comes with it does anyone have any idea if it's safe to replace it with an IR LED? Any ideas how much voltage the red LED's in the optical mouse uses?

 

[2xTrinity]

I tried modding the LED on one of my mice, an old logitech -- turns out it was current regulated and ended up supplying about 20mA to either a red LED (at 2.2v) or even a white LED (at 3.6V). This will probably depend on the LED. Switching for an LED that is the same votlage or lower (from red to IR) would probably work -- I'm actuaslly somewhat surprised they didn't go for an IR LED to begin with -- as that would make the whole thing invisible.

 

[TorchBoy]

I think it's probably a good idea that the stock LED is visible. If it wasn't an awful lot of people would pick them up and shine all that IR light straight into their eyes (without squinting or anything) wondering if their mouse was on. And they're quite bright.

 

[2xTrinity]

I think it's probably a good idea that the stock LED is visible. If it wasn't an awful lot of people would pick them up and shine all that IR light straight into their eyes (without squinting or anything) wondering if their mouse was on. And they're quite bright.

Hmm... that's a good point, didn't even think of that. Makes sense though -- a typical 5mm LED at 20mA drive would be bad to put a couple inches from ones eyeballs and stare into for prolonged periods, similar problem as green lasers with crappy IR filtering (though there you have a lot more problems if you try to stare into one ... even if it has good filtering...) Most of the newer mice seem to be going all black as well -- so even the red beam isn't really visible anymore, anyway. In the past optical mice used to be clear as if to "flaunt" that feature.

 

[TorchBoy]

Why are they red? Is it a matter of operating voltage, cost, spectral sensitivity of the sensor?

 

[2xTrinity]

Why are they red? Is it a matter of operating voltage, cost, spectral sensitivity of the sensor?

It probably has to do with sensitivity of the sensor more than anything. Swapping an LED such as a blue or white will still work, even in one that was orignally red -- it just won't be as sensitive on surfaces that aren't consistent. Although, there are some gaming mice that have blue LEDs in them for looks.

Also, one the one I took apart, the little scroll wheel actually has several small slots, an IR LED, and an IR sensor -- rolling the wheel on a typical optical mouse causes the slots to inetrrupt the beam at a readable rate.

 

[True]

Actually, most old ball mice were optical in nature - the ball moved a horizontal and vertical bar, which had slotted wheels at the ends. Between these were a light source and a receptor - when the mouse was moved, this would cause the slotted wheel to turn, cutting off then allowing the light to pass at a high rate.

As far as the topic goes, I have swapped IR into a mouse and it worked fine. I have also swapped high intensity blue into a few mice, and all worked fine as well. One wireless one in particular would turn the LED off earlier than it would with red, then it'd flicker on / off at .8-2hz or so, so the mouse would seem like it was turning on / off rapidly... if you are doing this to a wireless mouse, this would be my only concern.

And yes, the red LED is reusable (most use a 5mm LED), but why not just buy a package of them for cheap?

 

[Robban]

My first thought is that they probably had a pretty good reason for going with a red LED. By changing it to IR you might make your mouse "blind". Of course I have no idea if that's the case (and True's experiences would seem to indicate that I'm completely wrong) but my gut feeling goes along the lines of "if it aint broke..."

 

[johnny13oi]

Actually, most old ball mice were optical in nature - the ball moved a horizontal and vertical bar, which had slotted wheels at the ends. Between these were a light source and a receptor - when the mouse was moved, this would cause the slotted wheel to turn, cutting off then allowing the light to pass at a high rate.

As far as the topic goes, I have swapped IR into a mouse and it worked fine. I have also swapped high intensity blue into a few mice, and all worked fine as well. One wireless one in particular would turn the LED off earlier than it would with red, then it'd flicker on / off at .8-2hz or so, so the mouse would seem like it was turning on / off rapidly... if you are doing this to a wireless mouse, this would be my only concern.

And yes, the red LED is reusable (most use a 5mm LED), but why not just buy a package of them for cheap?

I currently use a wireless mouse and it does this. I believe this is to conserve energy. At first my mouse flickers really quickly so that it could still detect movement but just not as precise. Then it goes down to slower and very slow as if it were a heartbeat. This is most likely to keep it flashing every now and then to detect movement if there is any and turn it on back to full power. All of this only starts after the mouse sits untouched. Once the mouse detects the movement, it always switches back to full power.

 

[riffraff]

I get about five feet of throw with the stock LED in my tailless Logitech MX700! :twothumbs

 

[raythompson]

I get about five feet of throw with the stock LED in my tailless Logitech MX700! :twothumbs

Beamshots?