View Full Version : how to vary speed

02-12-2007, 05:22 PM
hello.. in th last topic i posted . i think i didnt explain myself well but anyway..

can anyone tell me how to control the speed of a motor wirelessly (by radio modules. and not more than 30mt range indoors needed) and where i can buy please.. dont be shy to give me any ideas :D

02-13-2007, 12:05 AM
what do you think about PWM??????

02-13-2007, 06:11 PM
hey thanks .. pulse width modulation is great .. but can anyone suggest me a transmitter.reciever for pwm ( preferable 6or more channels)

02-13-2007, 06:48 PM
Dude i was hoping you will get solution for that problem yourself which is just a two or three net searching and some thinking away........

anyways you should do this (only a suggestion) go with serial rx tx module, then send the control commands in byte format and then decode on the receiver side, if you look carefully at this you can control virtually any number of devices by wireless communication.........

yeah by this method you cannot transmits AV but it is an another topic

02-13-2007, 09:29 PM
hey thanks alot .. i only asked for a suggestion since this is my first try on robotics .. but ill fgure something out

02-14-2007, 05:41 PM

This is for 8051 microcontroller, for other controllers u have to modify the code.

To control the speed of the car use PWM. In 8051 use the Timer0 to generate the PWM wave.

Part of code for PWM:

setb EA - enable all the interrupts.
setb ET0 - enable timer0 interrupt.
Set the TMOD to to 03 for 8 bit operation or 01 for 16 bit operation.

Use one register to change the pulse width.

Go to http://www.iguanalabs.com/pwm.htm for sample code.

By varying the value of register the speed of the motor can be changed.