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Step 2Test your LED
Before tearing anything out, make sure the LED will work.
To do this, plug in the mouse and simply touch the leads from your LED to the same corresponding leads of the one thats already installed.
Make sure you have the leads correct; it is a diode and only works one way.
The red LED found in most standard mice is a 1.7V rated diode, and that resistor is holding the power down to that level so the LED doesn't overheat and burn out.
If your LED does not light up, and you have it positioned correctly, then it is not receiving enough power.
Mine was not getting enough power using this method.
Connect a multimeter to the leads of the installed LED to see how much voltage is actually going across it -both at idle and when the mouse is moved.
If you are not getting enough power for the LED you want to put in, use the multimeter to see how much power you would have if you override the resistor.
To do this, place the black prod from the multimeter on the anode of the led (negative side) and the red prod on the other side of the resistor than the LED is connected to.
Conveniently enough with this mouse, the voltages were (I believe) about 3.2V at idle and 5V when moving.
To test the override, reposition your LED in the same place you just put the multimeter.
As you can see, the two LEDs had consistent luminosities.
If your LED still won't light up, find a lower voltage LED.
If your LED is too bright, consider some smaller resistors to replace the installed one with.
Ultraviolet LEDs have the lowest wavelength, and thusly the highest voltage required to light em.
Blue LEDs are the next down on the list
Followed by Green and the rest of the visible light spectrum in it's order.
Red are just the most common used because they consume the least power other than Infrared. I don't believe infrared light can be sensed by a standard mouse eye though. (some higher end mice do have infrared LEDs)
To find the right resistor without guessing, you'll need some good ol' evil- i mean... math.
You have resistance (r), voltage (V), and current (I, uppercase "i")
The resistance is measured in ohms, the voltage in volts, and the current in amps.
Current = Voltage/resistance -or- I = V / r
the circuit in mice will usually be running at .02 amps. So the resistance you need to drop the voltage by half a volt (.5V) can be expressed by the equation:
r = V / I
r = .5 / .02
r = 25 ohms
so you would need a 25 ohm resistor in that case.
Here's an easy calculator for power and resistance and such:
http://ledcalc.com/#
To do this, plug in the mouse and simply touch the leads from your LED to the same corresponding leads of the one thats already installed.
Make sure you have the leads correct; it is a diode and only works one way.
The red LED found in most standard mice is a 1.7V rated diode, and that resistor is holding the power down to that level so the LED doesn't overheat and burn out.
If your LED does not light up, and you have it positioned correctly, then it is not receiving enough power.
Mine was not getting enough power using this method.
Connect a multimeter to the leads of the installed LED to see how much voltage is actually going across it -both at idle and when the mouse is moved.
If you are not getting enough power for the LED you want to put in, use the multimeter to see how much power you would have if you override the resistor.
To do this, place the black prod from the multimeter on the anode of the led (negative side) and the red prod on the other side of the resistor than the LED is connected to.
Conveniently enough with this mouse, the voltages were (I believe) about 3.2V at idle and 5V when moving.
To test the override, reposition your LED in the same place you just put the multimeter.
As you can see, the two LEDs had consistent luminosities.
If your LED still won't light up, find a lower voltage LED.
If your LED is too bright, consider some smaller resistors to replace the installed one with.
Ultraviolet LEDs have the lowest wavelength, and thusly the highest voltage required to light em.
Blue LEDs are the next down on the list
Followed by Green and the rest of the visible light spectrum in it's order.
Red are just the most common used because they consume the least power other than Infrared. I don't believe infrared light can be sensed by a standard mouse eye though. (some higher end mice do have infrared LEDs)
To find the right resistor without guessing, you'll need some good ol' evil- i mean... math.
You have resistance (r), voltage (V), and current (I, uppercase "i")
The resistance is measured in ohms, the voltage in volts, and the current in amps.
Current = Voltage/resistance -or- I = V / r
the circuit in mice will usually be running at .02 amps. So the resistance you need to drop the voltage by half a volt (.5V) can be expressed by the equation:
r = V / I
r = .5 / .02
r = 25 ohms
so you would need a 25 ohm resistor in that case.
Here's an easy calculator for power and resistance and such:
http://ledcalc.com/#
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Jul 21, 2009. 6:42 PMBriguy9
says:
I have one of those IR mice. It has the same thing on the bottom as a red LED, but it's in a little hole and it's tiny, and no light coming from it. Also, it works like the best mouse i've ever had. Another thing: It's wireless!
Reply
Jul 21, 2009. 6:44 PMBriguy9
says:
Actually I just looked at it and if you look at from the perfect angle you can see a tiiny red led pulsating on and off at about 6 times per second.
Reply
6
Dec 17, 2009. 7:30 PMlilpepsikraker
says:
That's not IR you are seeing. Look through your digital camera/cell phone camera, you should see the IR light being emitted, as cameras can "see" IR light.
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