Voltage step up

[Zabee.Khan]

Hi,

I'm working on a project where I need to control the speed a dc motor (basically controlling the speed of a small car). This controlling of motor speed has to be done based on the ldr values. I'm using arduino board to read ldr values and based on those values im sending analog signals. But the volt of this varies and is less then 3 volt. I need -+9V to make the motor working. Can you please tell me how can i do this. I have tried step up but for some reason it is not working. i guess because the voltage is analog(varying), i dont know!

Baseline is, I'm using ldr to control the speed of the motor and using arduino to do it. The output im getting from arduino is 3v and i need 9v for motors to be running.

Your help would be appreciated!
Thanks.

 

[waross]

Use a 9 volt motor controller with a 9 volt supply.
Use the Arduino to control the motor controller.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[LionelHutz]

Convert the analog to PWM inside the Arduino and output that signal. Feed it into a motor controller board that takes a PWM signal. You can get a small board cheap that will do this from Ebay or Amazon.