Hi everyone, ok i'll get to the poin on this one.

I've got a big presentation tomorrow on college and the main dish for the recipe is an mbed and a wifly module.

Yesterday everything was working fine, while readjusting the circuit on breadboard something happened and everything is down (even the wifly).

I don't know if this is an issue regarding power and voltage distribution but here's the circuit:

I don't know if my mbed is dead and wifly module too... I've connected a battery to a 7805 for constant voltage ...

Leave your opinion on the power supply (capacitors are there for spike protection).

Thanks for the support

Hi Samuel,

Can you try to plug your mbed to a computer over usb and check if you can run an Hello World program ?

Sam

Hi Samuel,

When I connect my mbed to USB nothing happen, not even the led turns on thanks

Is the mbed then disconnected from everything else? Does the USB storage device of the mbed appear?

Hi Samuel,

The LED not coming on is not a good sign, as this means the mbed isn't powering from USB. There is a current limiter on the mbed which (if abused) can fail, preventing the mbed from powering over USB.

You could try powering the mbed from the GND/Vin pins as shown in your diagram.

Assuming your battery is less than 12v, you can try powering it without the 7805 circuit, to see if the mbed can be powered from Vin.

If you cant power from Vin, then it sounds like the mbed is indeed dead. The most common failure is putting more than 5v on a GPIO pin, or drawing excessive current from a GPIO pin.

Thanks, Chris

I tryied to plug the Battery directly into Vin/GND The voltage regulator from the power input side (left side of mbed) gets really really really hot

So with direct power the voltage regulator goes off temperature, and by that i mean really hot.

I'm guessing that I just f$#$!ed everything up on my circuit and now my final presentation tomorrow is doomed.

Got any suggestions to check if mbed is really dead? (circuit etc?) Tips for changing any mbed's little chips? =F

(I would like to refer that my brain is also burned)

haste makes waste.

9V is not 5V is not 3.3V. EE 101 needed.

so i just figured out the problem,

I was using another voltage regulator (LM317) for another IC that was connected to an mbed GPIO.

This regulators, LM317 and 7805, when connected to the same GND as mbed seem to don't like each other because one of them (randomly who starts first) gets really really really hot, but without the mbed on the circuit they run OK!

So i figured that the regulators and the mbed just don't match....

Solution: drop the LM317 and let the mbed internal regulator do the job.

I'll post this project on cookbook page.

Thanks all for the support and feedback on this one.

OH! about the project...it went ok! (my colleague lend me his mbed ehe )