Theoretically speaking you do need the capacitor, otherwise you'd need to start the motor by manually rotating the shaft.

I say "theoretically" cos I've never gone and tried this myself...

That's fine, the only disadvantage to using an over-rated cap is the size, really. Usually AC motors have big metal oval-shaped caps (they're unpolarized electrolytics, I believe). You'd probably want one of those.

May as well just get both; capacitors aren't horribly expensive. I don't think the 25uF cap would hurt the motor if it wouldn't even start with the 15uF one.

I think he runs operatorchan.

Yeah, safety glasses are always a good idea when shooting anything. A $1 bit of plastic that can save your eye? Sign me up.

I find that galvanized steel and copper are readily available in Canada. They don't come in good sizes for combustions, but for pneumatics it's golden stuff. It's expensive, but given the right valve you could take your cannon to several hundred PSI.

I got that ebook, I'm uploading at this moment... Edit: There you go: http://rapidshare.com/files/211551990/101_spy_gadgets_for_the_evil_genius_0071468943.pdf.html O and btw you could've tried to download it with a torrent program(like I did :roll: ) Thanks! I was looking for a mic preamp circuit t...

Sounds cool, but it also sounds like that would be one hell of a mess to clean up

DWV ABS is also safer than DWV PVC (better failure characteristics and impact resistance).

Nicely done, now just replace that bungee cord with some surgical tubing and she'll really fly

Well, either way, the best place to start would be to have a looksee at the USB root hubs in Device Manager. Another crazy idea would be to boot into a Linux distro and try it there. This would clear up the hardware/software dilemma. A small PMDC motor running shouldn't kill the port, but a motor st...

Did the motor have any sort of back-emf protection (a diode in antiparallel does this)?

(May not make much of a difference in this case, but you never know.)

Does the port work with any other devices?

Nice cannon, especially for a first!

covey12 wrote:some oh yeah, ill give 25 dollars to anyone who puts there finger between those screws

While I haven't put my finger in that specific setup, I've zapped myself with a BBQ sparker before...can I still have $25?

Newgrounds has user-made audio tracks which I believe are free to use.

Demon wrote:
(My dad, even if he is very strict on the law, was saying c'mon, potatos dont counts, they cant be dangerous)

Oh, they can be very dangerous coming from a potato cannon.