I have a 12V 1.6A DC power supply that I scavenged from some old piece of computer hardware. It is center positive (verified through my voltmeter).
I tested the supply without load (nothing plugged in) and it hung around 12.2V, so I think it is regulated (doesn't go to high voltage when not under load).
So is this a good power supply? Does the amperage matter?
Note I want to run a couple of 12V 0.17A blowers AND the Arduino off this... but the number of blowers connected at any one time will be variable (could be 2 could be 0).
The "amperage" isn't a rating that can break the Arduino, as that's the maximum the power supply is rated for (it will supply a different amperage depending on the load). That being said, you don't want a power supply with too low of an amperage rating, as it may not be enough to run the Arduino. Yours is fine for that purpose.
One thing you may want to watch out for is how much you are running off of the regulated 5V. I tried to run two servos off of 5V regulated from a 12V wall wart, and the regulator became VERY hot. I was lucky enough to feel the regulator before it exploded :P. So you may want to monitor the regulator and assure that it doesn't overheat.
If you're running the blowers from VIN or some other way not through the regulator, you should be fine, just be careful not to overload the power supply.
PS: As a useful bit of info: If you accidentally plug in a center-negative supply, as long as it's not too much power, it shouldn't hurt the board, as there is a diode in place to protect from that (but you should also know that the diode does not protect from plugging cables in reversed to the VIN and GND connections).
most arduinos come with a 7805 voltage regulator, which 12 volts is fine, It will become hot without a heatsink so keep an eye on it
BUT there are some boards (the modern device barebones for example) that come with a tiny LDO regulator, which 12v would really be pushing its max
see what you have, just to make sure, and try and figure out how much current your going to be drawing tru it (a 7805 should be ok @ 12v with a really low current draw, its fine for me with a tiny heatsink up till near 500ma with a 12v supply)
Coincidentally, is there any way to attach a heatsink to the Duemilanove's Voltage Regulator? It gets a bit hot sometimes, and I'm curious if it's possible to cool it down a bit without major modifications.
Coincidentally, is there any way to attach a heatsink to the Duemilanove's Voltage Regulator? It gets a bit hot sometimes, and I'm curious if it's possible to cool it down a bit without major modifications.
I dunno, is it soldered to the board, is it like the one on the homepage where the tab has not been cut off and there is a mounting hole?
if no its not soldered and yes it does have the mounting tab, then yes you can slide one of those U shaped heatsink's under it and bolt it to the board ... its what I have on mine and eventho it is no where near what I would like to have, it does help
Ah, good that MOSFET schematic is a good one. If you find the MOSFET gets hot, try replacing it with a FDP61N20. It's a similar FET, but with much lower 'on' resistance. So it will run cooloer and let your blowers run slightly faster.
If you're good with soldering, you can replace the on-board regulator with a standard TO-220 size 7805 and a heat sink.
Using these blowers connected to the damper of a BBQ smoker. If you have temperature sensors, you can control the temperature you cook at by blowing more or less air on the fire. Arduino does control, reads the temps and controls the fan. See my link above.
