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ArcticMyst Security by Avery

ipod touch laser

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Oct 27, 2011
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hi I'm trying to make an ipod touch laser pointer that connects into a dock connector. I know that it outputs 3.3 volts but how many milliamps. iI there an equation to find the amount of milliamps? does any body know how much it outputs?
 





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Feb 28, 2011
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I'm assuming you want to make your own laser pointer from a bare diode.

I don't think you should depend on the output current limit of the iPod. For a start, all iPods are slightly different and all have different current limits on the 3.3v output, as far as I know. Just to be safe, I would assume it's capable of supplying infinite current and destroying the laser without current limiting.
The output is probably very well regulated since chances are its the same supply for all the sensitive 3.3v things inside the iPod. Because of this you could probably get away with just connecting your laser diode in series with a suitable resistor to the output. Probably stick a cap or two is parallel too, just to make sure.
 
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hi I'm trying to make an ipod touch laser pointer that connects into a dock connector. I know that it outputs 3.3 volts but how many milliamps. iI there an equation to find the amount of milliamps? does any body know how much it outputs?

5v @ 20mA out is the maximum that iOS allows for any given device. That being said, you can power any device using a USB hub and ipod touch as long as the hub is powered!
 
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Seoul_lasers said:
5v @ 20mA out is the maximum that iOS allows for any given device.
Huh, didn't know they even had a 5v output. Unless you mean 3.3v, in which case 20mA doesn't seem right since i've seen GPS receivers running from an iPhone before...
 
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The current in iOS is set at 20mA! the GPS dongle is self powered or has a charge line in.
Sorry you are correct, it's a 3.3v raw off the rails, and then stepped to 5v using the camera connector. 20mA output limit!
 




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