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[on:]

Hi everyone, I hope some one can help...

I'm making a project based on this concept:

http://blog.jpcarrascal.com/2010/03/look-ma-no-wiimote/


Basically, after setting up the transmitter...

(Consisting of a Pro Mini [5v], Xbee + Xbee explorer (Regulated), the insides of a Wii Nunchuck, and a power regulator (solely for powering the nunchuck at 3.3v))

... and having it plugged into a standard ProCell 9v battery on about 5 different occasions, one of the capacitors (That I assume is part of the Pro Mini's power regulation) exploded when I plugged the battery into it...

I tried to whip the battery off, to no avail. The capacitor (labeled c106, and positioned next to the raw and gnd pins) sparked off pretty brightly, and smoked for a couple of seconds... Looking at the capacitor, it's cracked down the centre...

What I really want to know is, was the component faulty, or was it something I did... I've brought another one, but I don't want to replicate the explosion... It's part of my final year Dissertation at university, and I'm quickly running out of time...

Thanks for your time! Hope knows...

Nick

[Reply #1 on:]

Sounds like it was faulty - its the decoupling cap for Vin and 9V isn't unreasonable for Vin - the other possibility is you connected power backwards - which would have damaged more than the cap.

If its just the cap you could use should desolder the remains and either replace it (10uF) or use a decoupling capacitor off the board - depending on how good your surface-mount soldering skills are.

[Reply #2 on:]

What I really want to know is, was the component faulty, or was it something I did..

Hard to tell but my guess would be something you did. A further guess would be that you are connecting power to the wrong place or the wrong way round.

having it plugged into a standard ProCell 9v battery on about 5 different occasions, one of the capacitors ..... exploded when I plugged the battery into it

Are you saying nothing had changed between the successful connections and the explosion? On the occasions it did not explode (I can't believe I just wrote that) did it work as expected or was it dead?

[Reply #3 on:]

If its just the cap you could use should desolder the remains and either replace it (10uF) or use a decoupling capacitor off the board - depending on how good your surface-mount soldering skills are.

Thats good to know! I'll try that, may need a back-up at some point.

Are you saying nothing had changed between the successful connections and the explosion? On the occasions it did not explode (I can't believe I just wrote that) did it work as expected or was it dead?

I had changed a couple of things, but it was the time before I plugged the battery in for the last time... (If you get me?)



On connecting the battery the wrong way round, I definitely didn't when I plugged it in that time, but I may have caught the pins the wrong way at some other point...

Thanks for your insight guys!

[Reply #4 on:]

... did it work as expected or was it dead?

It definitely worked as expected, I'd tested it using the blink sketch, and I used the Xbee's to work the Physical Pixel Sketch on the pro mini.

Thanks again.

[Reply #5 on:]

but I may have caught the pins the wrong way at some other point...

That might have damaged the capacitors causing a short in them. This then would have been enough for it to over heat and explode when it was connected the right way round for a little time.
In over 40 years I have not known a capacitor explode for no reason, it is more likely you damaged it than it was faulty to begin with.

[Reply #6 on:]

but I may have caught the pins the wrong way at some other point...

That might have damaged the capacitors causing a short in them. This then would have been enough for it to over heat and explode when it was connected the right way round for a little time.
In over 40 years I have not known a capacitor explode for no reason, it is more likely you damaged it than it was faulty to begin with.

OK, I'll pay a special attention not to do this...

Thanks for your help.