help to identify this diode - Page 1
Forum section: electronics / beginners

author: 4serge
author_rank: Newbie
timestamp: December 31, 2018, 07:46:29 am
content: Hi everyone! Here is my first post here.I need help to identify LED in the attached photo (or whatever it is) and to source the replacement.this is from roller mousehttps://www.contourdesign.com/product/rollermousepro3/happy new year!

author: Brumby
author_rank: Unknown
timestamp: December 31, 2018, 07:54:53 am
content: What makes you think you need to replace it?

author: ataradov
author_rank: Super Contributor
timestamp: December 31, 2018, 08:26:46 am
content: And if you really need to replace it (highly unlikely), you would have to look at the sensor model. You are not likely to find the complete datasheet, but you may at least find the wavelength. You need to find an LED with the same or similar wavelength.Although those sensors have pretty wide sensitivity range, so any random red led may work.

author: Brumby
author_rank: Unknown
timestamp: December 31, 2018, 08:50:40 am
content: What if it's an IR LED?

author: ataradov
author_rank: Super Contributor
timestamp: December 31, 2018, 08:53:56 am
content: Quote from: Brumby on December 31, 2018, 08:50:40 amIt is possible, of course. But that looks like a standard Avago sensor that uses visible light.

author: exe
author_rank: Unknown
timestamp: December 31, 2018, 02:55:20 pm
content: I wonder if it really needs to precisely match the old part. Afaik these sensors are 32-pixel cameras, they are most sensitive to red (or IR), but I doubt a small shift in wavelength will make it completely non-functional. In the worst scenario it will work bad on dark surfaces. I just took my mouse with IR led, and moved a red led over the sensor lens. The cursor seemed to be moving. I don't have an ir led to compareI wonder how it happened that only the diode died, but not the circuitry around. Are you sure you need to replace (only) the diode? BTW, to check if sensor is alive, I think you can just light directly on it to see if

author: 4serge
author_rank: Newbie
timestamp: December 31, 2018, 10:09:47 pm
content: Thanks for all the replies. This LED has very low intensity (you can barely see it) when the the roller mouse plugged in and the cursor does not move with roller bar .. So I guess it is either power supply which powers this LED or LED itself. ..I was wondering if I should take apart regular optical mouse and get the LED out of it ... it is likely they used the same one, in this roller mouse it just looks up on the roller bar rather than on the mouse pad...

author: ataradov
author_rank: Super Contributor
timestamp: December 31, 2018, 10:12:58 pm
content: It is likely that the LED is fine. In my trackball that works on the same principle, I see no visible light at all.Can you read the model of the sensor?

author: wraper
author_rank: Unknown
timestamp: December 31, 2018, 10:23:33 pm
content: Quote from: 4serge on December 31, 2018, 10:09:47 pmIs it recognized by OS to begin with (device manager)? It might be IR led, sometimes you can see a bit of visible red light from them. Also it's powered from sensor, so it might be just a dead sensor.

author: wraper
author_rank: Unknown
timestamp: December 31, 2018, 10:27:31 pm
content: BTW considering 1648 date code on the PCB, it still should be under it's 2 year warranty.

author: Jwillis
author_rank: Super Contributor
timestamp: December 31, 2018, 11:49:42 pm
content: Check it with with the diode function on your multi meter.If it has a forward voltage of 1.5V and it doesn't shine its probably an IR LED.If it has a forward voltage of 3.6V then it's probably an UV LED.If you get no forward voltage then it's dead.Red to yellow to green LEDs will be typically 2V to 2.2V forward voltage .Blue to UV are typically 3V to 3.6V.White has UV elements so typically have 3V Forward voltage.This chart doesn't have IR LEDs but they have forward Voltages as low as 1.5V .Because a DMM puts a voltage across the LED ,visible ones should shine.