Hello again,

I know mbed is a prototyping microcontroller (but I'm too cheap to buy another :P), but would it be possible to power the LPC1768 with a battery? I.E the battery goes to a USB out, and that USB out goes into the USB in on the mbed, hence powering it.

Would this be possible? And what voltage and ampage can the mbed take (if anyone knows)?

Thanks,

Dom.

Hey Dom,

If you notice on the pin card you got with your mbed pin 2 (VIN) can take from 4.5 v to 9.0 v of power. If you just connect the + of the battery to pin 2 (VIN) and the - to pin 1(GND) your mbed will be powered and wireless :)

Ohh, cool! Will try that when my breadboard comes.

Once again, thanks, Vlad!

If i did, by accident, reverse the polarity of the battery holder, that would effectively murder the mbed, right?

And how do I know the polarity of my battery holder? I know it's a stupid question, but i don't want to kill something that would cost me £45 to replace. It's a 3x battery holder. I'm guessing it's just that the pins are the polarity of the side of the battery they are nearest too, right? Or is it the other way round?

Dom Johnson wrote:

If i did, by accident, reverse the polarity of the battery holder, that would effectively murder the mbed, right?

An easy was to check for polarity is using a multimeter. Place one wire on the red and one on the black, and if you get a positive voltage then the one connected to your red is positive, if its a negative voltage then the wire on the red is negative.

If you do not have a multimeter just connect the battery pack to an led and see which one is + and -, if you include a picture of your battery holder I could probably tell you which one is which.

Worst resort is just to follow the logic of the battery holder, track the + charge thought the batteries and see which wire it is connected to.

A current limiting resistor will be needed for the LED!

Leon Heller wrote:

A current limiting resistor will be needed for the LED!