maemo.org - Talk - View Single Post - The Ludicrous N900 Powermat Mod

Wonko	2011-05-10 , 20:33
Posts: 456 \| Thanked: 1,580 times \| Joined on Dec 2009	#19

Originally Posted by woody14619

I plan on putting a micro reed relay (or maybe a low power opto-isolator?) in to short the data pins activated by current from pad itself, so it auto-closes the connection when it's powered by the pad. That should take less than 10-20mA for an opto-isolator...

Using an opto-isolator seems to work quite well.

Thanks for that hint. I made an improved mod that uses such an opto-isolator (Optokoppler in German) to short-circuit +Data and -Data. I attached an image of the actual circuit I am currently using.
The diode BY 133 is used to protect the Powermat receiver from the USB +5V voltage and to prevent the opto-isolator being activated when the N900 is attached to a common USB port/charger.
Furthermore, I am now using the receiver part of a Powermat Nintendo DS Lite charger. This one is slightly thicker and requires more manual work in order to being attached to the N900 battery cover. Though it has the benefit that it is not as complicated as the Iphone 3G version and occupies a smaller area. I'll let you know how this one works out...

Attached Images

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Last edited by Wonko; 2011-05-16 at 15:39.

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