It is my first time posting, and i have very low electronics knowledge. My problem is, i need to control a motor, from my arduino Duemillanove, but the motor needs a voltage arround 9.6V, which afaik the arduino cant power. I have tried searching for a solution over the internet. One that looked easy, was using a Voltage Doubler Chip ( MAX1682 / MAX 1683 ) but the problem is i cant find it at a local distributor, so i have to buy it online from another country ( I live in Greece ).
So my question is, what do you suggest as a solution?
I'm an arduino noob, but as I understand it, the board cannot supply enough current to run a motor. There are several places that sell the "motor" shield. That should be able to run your motor.
You definitely cannot drive a 9.6V motor from USB, so you need to power the Arduino board form a 9 or 12V wall power supply. Then you can use a motor shield to drive the motor. The motor driver in the motor shield has a special IC that can take PWM (analog out) for speed control and a Digital pin for direction control from the Arduino board, and control or drive the DC motor.
How much "control" do you need? Just on/off? Speed? Forward + reverse?
If you don't need to reverse the motor, it's easy to turn it on and off, and/or control the speed, just by adding a suitable transistor and resistor to one of the Arduino's digital pins.
Actually i havent bought the motor itself. i bought a whole RC Car, from a local store. its a cheap one ( 20 Euro ) Made in China. So dont expect any documentation. So i used my multimeter, and i found out that on the motor there are 8.9-9.5V .
I was thinking if i could use an external supply for voltage on the motor, like the battery pack that comes with the RC Car, and just ground it to the arduino, to control it. But now the problem is that i cannot use the reverse, nor control how fast it goes i guess.
I Would like to both do forward, backward. Isnt there a way to increase the voltage on a circuit? Like a chip or something.
You'll need a motor sheild, or if you want to save money, you can buy an l293D, there are example applications on the data sheet, try searching for bridge motor driver on google to find out how they operate.
You're on the right track with the dual power supply: that's how it's customarily done.
For on-off control of high-voltage devices like motors, the usual approach is to connect the + side of the supply to the motor, and have the microprocessor control the connection to the - side through a transistor. You can find lots of examples of this on the web. You can control the speed by turning it off an on very fast, for a varying percentage of the time, using the PWM output.
For reversing control, you'll want to use an "H-bridge" chip like the L293. It combines a bunch of transistor switches with the circuitry to translate between the microprocessor's logic voltage and the motor's
voltage. You can find lots of info and examples of this on the web, too.
Two things you should be aware of: RC car motors use a lot of current. More than the L293 and friends can handle. You'll need to find a "heavy-duty" chip to control it.
The other thing is that RC cars usually "abuse" their motors: they run them at voltages and currents way above their design specs, burning them out in hours (or even minutes), instead of months or years, to get lots of power out of a small package. You might well find that your "9V" motor was actually designed to run at 6V, and will last longer if you run it at a lower voltage.
btw, a 20-Euro car probably doesn't have a separate radio and motor control, but you should check: you might be able to control the motor by connecting the Arduino to the car's motor control, and have it pretend to be the RC receiver.