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iMac 2008 24" external display conversion...and USB camera failure.

Joined
Aug 17, 2018
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HP
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EliteDesk
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AMD
Hi All,

When my 2008 24" iMac's video card died a few years back I finally decided to turn it into an external monitor. It's largely worked quite well; removed most of the components from the case, found a display controller on eBay and got it working over HDMI using the original power supply, along with the speakers. I also succeeded in getting the original bluetooth and IR modules running over USB, using pinouts from schematics I found on the interwebs.

However, my USB conversion of the built-in camera (iSight?) has refused to be recognised, not by the USB bus on my macbook, nor by that of my desktop running Ubuntu linux -- no sign of life whatsoever. I've seen several accounts here and elsewhere of people getting these cameras working over USB, and I had success with the other USB devices, so I'm just wondering if there's a trick to it that I'm missing or if it really is dead. I've juggled some of the wires around in trial and error, so I guess I may have fried something -- for example, I've noticed that when I connect the ground and +5V USB lines to the camera (assuming I got the pinout right), the voltage across ground and the positive USB signal terminal of the camera is over 3V, while that between ground and the negative USB signal terminal of the camera is on the order of millivolts -- this suggests to me something is wrong as I'd expect the two USB signal terminals to be at similar voltages, but I confess I know next to nothing about how USB actually works.

Any wisdom from the forum is most welcome, thanks in advance.
 
Last edited:
Joined
Aug 17, 2018
Messages
17
Motherboard
HP
CPU
EliteDesk
Graphics
AMD
Follow up in case anyone comes across this: guess what -- turns out it was the effing USB cable I was using; tried a different (shorter) one and now the camera is recognised. It behaves a bit erratically, but is definitely working.

Also: I did some reading around the USB protocol and apparenlty yes 3.3V is precisely what you should expect on one of the data pins (+ for full speed, - for slow) when a device initialises.
 
Joined
Apr 23, 2020
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I didn't read
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the RULES
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Follow up in case anyone comes across this: guess what -- turns out it was the effing USB cable I was using; tried a different (shorter) one and now the camera is recognised. It behaves a bit erratically, but is definitely working.

Also: I did some reading around the USB protocol and apparenlty yes 3.3V is precisely what you should expect on one of the data pins (+ for full speed, - for slow) when a device initialises.
do you know the pinout for the microphone? i’m doing the same thing and i got the camera working but can’t figure out the mic?
 
Joined
Aug 17, 2018
Messages
17
Motherboard
HP
CPU
EliteDesk
Graphics
AMD
Mine had two black wires and one brown wire -- the brown is the signal, the other are grounds. It's analog audio so I wired it to a 3.5mm jack (signal at the tip) and used the microphone port to test it...I don't use it regularly.
 
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