GP32 9.6v battery + resistor = usb powered?


ZiUL

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I was wondering if it's possible to use a 9.6 or other kind of battery (look here) with the gp32. Is it possible to use a resistor to down the voltage to 3v? If so, you could in some way power up the usb port and the smc card reader... It's just an idea, I don't know if it's possible (or if you guys did understand my explanation)

Well.. that's it...
 
Firstly, as far as I know, it'd take more than a resistor to down the voltage to 3v - that would require a step-down transformer....

bulk.... pain in the ass to make....

etc

is it worth it?
 
It should be possible. But the usage of resistors or such things are not apropriate. Using a voltage regulator associated with a heatsink would do it well.
 
Adendum to my previous post :

USB requires +5V to be powered. So two voltage regulators are needed : one for +3V and one for +5V.



Athaniel@wanadoo.fr
 
or we can use a 5v battery and just one voltage regulator to 3v
 
Another prob is that 5V cards are shaped diffrent from 3.3V (corner cut is on opposite side) so you would have to mod the port for it to fit. Also I'd rather carry around 2 128's than a GP32 2ice as heavy (I have a HUGE digi cam that uses a Li-Ion 9.6V and the battrey is 2ice as heavy as the cam!)
 
You could use a simple voltage regulator and 2xAAs (~6v) to make 5v and 3v. I've a figure of 180ma as the max current for USB in my head, (but thats prolly wrong!!!), which would make the average set of AA batteries last for ages!

You could build up a simple voltage divider circuit for a keyboard of a known current requirement that might not fry the GP32, but for the trouble the above voltage reg would be nearly as easy and offer peace of mind as well as low voltage (ie flat battery) drop out.

If anyone is game, I'll supply rough schematics and actually look up the real specs....



(btw, i'm not game)
 
2 x AA batteries = 3 volts not 6 volts

Its possibly easier to have a small external box to power the USB keyboard etc, and have a set of good batteries in the GP32. There are chips that will take 3 volts to 5 volts but they will only drive small power loads. There are a number of small PDA/mobile keyboards the could be hacked to work through the serial port, using USB would require software drivers to be written for the GP32. I think that the best solution is to use a 3 volt PIC microprocessor as an interface between keyboards, analogue joysticks, modems etc.
 
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