Hello
I would like to control 4 DC 12 V Fans with the Arduino. There is only a black and red cable on the Fan, so it will be not as easy as with a servo.
I guess I also have to use an external power supplier, but I might just buy smaller fans.
my guess is you could use about every tutorial on dc motors matching your specs. As far as I know, the third cable (if it was there in your case) is only for reading RPM anyways, not for setting them (might be wrong though...)
So just have a look for how to control dc motors (should work with a mosfet or something like that, but don't hook the motor directly to an arduino output pin!)
Its not something that is easy to calculate because you don't have information on how much current the servos will draw (this is dependant on the servo and the torque and is almost never accurately specified).
If you have a meter that measures current then you could run some tests to see how much current your components draw. If your 5 volts is provided by a USB hub, most will supply up to 500ma although some may be less.
I don't think you will damage anything but you probably won't get reliable operation powered from USB. 0.11 amp is low for a servo (if there is any significant mechanical load the current drain will be higher). And you need to add the current to drive the Arduino board.
I suggest you try a good quality 5v 1amp regulated DC power supply. These are often used to power computer peripherals so should not be difficult to find.
If it is not regulated (and its probably not) then the voltage will peak higher then the switch markings. If you have a multimeter you can measure the voltage to see what it actually is producing. I would not recommend running most servos on anything higher than 6 volts.
Hello
I bought an AC/DC power supply. I did not try it yet.
I have got the Arduino Duemilanove, I just went trough the hardware details on the website, but could not understand everything.
The AC/DC can provide me with 1200mA which is enough to power the
4 x 5V servos and
1=2 x 5V fan
After I plug the regulated P supply in, shall I use the Vin or the 5V pin the get the current? The USB is still going to be connected as I control the tools from the computer.
Shall I use the 6V from the P supply? (there is 4.5 and 7 as close alternatives)
Your fan is rated at 5 volts but your power supply does not provide this. You can try running the fans and servos from 4.5 volts and see if they have enough power.
To try this, you connect the +4.5 volts from the external power supply to the fan +5v line and the servo power line (the center pin of the servo connector). Connect the ground line from the external power supply to Arduino Gnd. That way the external power supply will drive the fan and servos, the USB will drive the Arduino board.
You could also try the 6v line but if that is not too much for the fans.
1, I do not connect the power supply to the Arduino instead I use PCB mounting socket and connect it to the breadboard.
2, from the breadboard I connect the power supplies current (4.5 V) with the servos and the fans.
3, from the breadboard I connect the power supplies ground the the Arduino's ground
4, the servos and the fans ground is going to be connected with the Arduino's ground or with the ground on the breadboard (power supply), or this does not matter, it works in either way?
1 , I do not connect the power supply to the Arduino...
only the ground from the external power supply is connected to arduino
2, from the breadboard I connect the power supplies current (4.5 V) with the servos and the fans.
yes, the +4.5 volts from the supply goes to the +voltage lines on the fans and servos
3, from the breadboard I connect the power supplies ground the the Arduino's ground
all the grounds must be connect together
4, the servos and the fans ground is going to be connected with the Arduino's ground
all the grounds - power supply, arduino, fan and servo must be connected together