Radio control of PWM motor speed? - Electronic Circuits Projects Diagrams Free

gregster · 16th February 2007, 01:42 PM

Guys can anybody help, ive found a PWM circuit online that works well for speed control of a dc motor, is it possible to replace the speed pot with the output from a radio control receiver and therefore control the motor using the transmitter? any ideas would be much appreciated, cheers

sam2 · 16th February 2007, 08:45 PM

How big is the motor? Voltage , current? There are alot of electronic speed controls out there for R/C. The largest ones I know of will handle 40 amps /20 volts, but I am sure there are much larger.
If the motor is alot larger you could always control the pot with a servo.

Sceadwian · 17th February 2007, 01:18 AM

Supply a link or post a schematic of the circuit you're using for the motor controller. Little to nothing can be suggested if you can't provide a schematic.

gregster · 17th February 2007, 11:44 AM

Thanks for the replies guys, here's a link to the circuit i'm using http://solorb.com/elect/pwm/pwm1/

What i wanted to do is replace the VR1 pot that controls the speed with the output from one of the channels of my receiver. I realise that there will need to be another circuit to convert the receiver output to a suitable format, just don't have a clue what it should be. I know it'd be easier just to use an ESC but I'm interested to see if there's a way of doing it myself. feel free to say if i'm asking the impossible!!!

Russlk · 17th February 2007, 01:00 PM

Assuming that the speed pot is only providing a voltage to the PWM control, a frequency to voltage IC would work.

**Nigel Goodwin** · 17th February 2007, 04:06 PM

Quote:

Originally Posted by gregster

Thanks for the replies guys, here's a link to the circuit i'm using http://solorb.com/elect/pwm/pwm1/

What i wanted to do is replace the VR1 pot that controls the speed with the output from one of the channels of my receiver. I realise that there will need to be another circuit to convert the receiver output to a suitable format, just don't have a clue what it should be. I know it'd be easier just to use an ESC but I'm interested to see if there's a way of doing it myself. feel free to say if i'm asking the impossible!!!

It's by no means impossible, just making it more complicated than it needs to be - you need to convert the pulsewidth to a DC voltage (0-12V), then feed that to the comparator input.

A frequency to voltage IC would be a nice idea, except the frequency does'nt change, just the pulse width.

**kinjalgp** · 17th February 2007, 04:13 PM

Quote:

Originally Posted by gregster

Thanks for the replies guys, here's a link to the circuit i'm using http://solorb.com/elect/pwm/pwm1/

What i wanted to do is replace the VR1 pot that controls the speed with the output from one of the channels of my receiver. I realise that there will need to be another circuit to convert the receiver output to a suitable format, just don't have a clue what it should be. I know it'd be easier just to use an ESC but I'm interested to see if there's a way of doing it myself. feel free to say if i'm asking the impossible!!!

What type of output does your receiver give?

gregster · 17th February 2007, 09:52 PM

It's a Futaba FM receiver, don't know if that means the output is FM as well?
Is there an IC i could use that will take the receiver output in at one end and throw a pulse width type signal out the other? that'd save me having to faff with two different circuits!!

**Nigel Goodwin** · 17th February 2007, 09:59 PM

You can do it with a PIC, which would be the modern method - but years ago ETI Magazine did just such an ESC. They actually did two different versions, to show different approaches, one analogue, and one digital - both gave similar results.

The servo outputs from the Futaba should be the standard variable 1.5mS pulses every 20mS.

gregster · 17th February 2007, 10:10 PM

Thanks Nigel, i'd like to learn more about PICs actually, i already looked at some of your tutorial pages!! forgive my ignorance but would i have to buy a specific type and then find the correct software or is a PIC a generic chip that can be programmed to suit any need?

**Nigel Goodwin** · 18th February 2007, 10:13 AM

Quote:

Originally Posted by gregster

Thanks Nigel, i'd like to learn more about PICs actually, i already looked at some of your tutorial pages!! forgive my ignorance but would i have to buy a specific type and then find the correct software or is a PIC a generic chip that can be programmed to suit any need?

PIC is a type of micro-controller from MicroChip, there are many other types available as well, but PIC's are the most popular ones. There are a number of websites that have radio control projects using them.

Here's one example:

http://www.eagleairaust.com.au/sampcode.htm

gregster · 18th February 2007, 01:01 PM

Thanks very much Nigel, and all the other guys who helped out, i'm off to learn about PICs!!!
Incidentally Nigel, are those circuits you mentioned from ETI magazine still knocking about? I'd be very interested to see them even though the PIC route is obviously best for my problem.

**Nigel Goodwin** · 18th February 2007, 01:03 PM

Quote:

Originally Posted by gregster

Thanks very much Nigel, and all the other guys who helped out, i'm off to learn about PICs!!!
Incidentally Nigel, are those circuits you mentioned from ETI magazine still knocking about? I'd be very interested to see them even though the PIC route is obviously best for my problem.

I can't even remember what year they were - but it was a LONG time ago, I 'might' still have the issue somewhere, but I have thrown a lot of older magazines out (I had a large collection, back to the 1950's).

gregster · 18th February 2007, 01:13 PM

Well please don't spend hours rooting through on my behalf!!!! though if you should happen across them i'd love to see em
Thanks again for your help, the muddy waters are clearing, bloody slowly mind!!!

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Title	Starter	Forum	Replies	Latest
Digital Proportional Radio Control	nye	Electronic Projects Design/Ideas/Reviews	11	21st April 2008 06:07 PM
dual PWM control of servos with 16f84	mrvanx	Micro Controllers	3	15th February 2007 08:51 PM
Automobile Interior Fan Control (PWM + Mosfet)	dext3r	Electronic Projects Design/Ideas/Reviews	4	20th January 2007 11:34 PM
Radio control with PIC16F84	jox3000	Electronic Projects Design/Ideas/Reviews	1	27th September 2006 05:13 PM
Radio remote Control	nye	Electronic Projects Design/Ideas/Reviews	2	19th November 2004 03:30 PM

16th February 2007, 01:42 PM	(permalink)
gregster	Radio control of PWM motor speed? Guys can anybody help, ive found a PWM circuit online that works well for speed control of a dc motor, is it possible to replace the speed pot with the output from a radio control receiver and therefore control the motor using the transmitter? any ideas would be much appreciated, cheers

16th February 2007, 08:45 PM	(permalink)
sam2	How big is the motor? Voltage , current? There are alot of electronic speed controls out there for R/C. The largest ones I know of will handle 40 amps /20 volts, but I am sure there are much larger. If the motor is alot larger you could always control the pot with a servo.

17th February 2007, 01:18 AM	(permalink)
Sceadwian	Supply a link or post a schematic of the circuit you're using for the motor controller. Little to nothing can be suggested if you can't provide a schematic. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."

17th February 2007, 11:44 AM	(permalink)
gregster	Thanks for the replies guys, here's a link to the circuit i'm using http://solorb.com/elect/pwm/pwm1/ What i wanted to do is replace the VR1 pot that controls the speed with the output from one of the channels of my receiver. I realise that there will need to be another circuit to convert the receiver output to a suitable format, just don't have a clue what it should be. I know it'd be easier just to use an ESC but I'm interested to see if there's a way of doing it myself. feel free to say if i'm asking the impossible!!!

17th February 2007, 01:00 PM	(permalink)
Russlk	Assuming that the speed pot is only providing a voltage to the PWM control, a frequency to voltage IC would work. __________________ see my website: www.geocities.com/russlk

17th February 2007, 09:52 PM	(permalink)
gregster	It's a Futaba FM receiver, don't know if that means the output is FM as well? Is there an IC i could use that will take the receiver output in at one end and throw a pulse width type signal out the other? that'd save me having to faff with two different circuits!!

17th February 2007, 09:59 PM	(permalink)
Nigel Goodwin	You can do it with a PIC, which would be the modern method - but years ago ETI Magazine did just such an ESC. They actually did two different versions, to show different approaches, one analogue, and one digital - both gave similar results. The servo outputs from the Futaba should be the standard variable 1.5mS pulses every 20mS. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

17th February 2007, 10:10 PM	(permalink)
gregster	Thanks Nigel, i'd like to learn more about PICs actually, i already looked at some of your tutorial pages!! forgive my ignorance but would i have to buy a specific type and then find the correct software or is a PIC a generic chip that can be programmed to suit any need?

18th February 2007, 01:01 PM	(permalink)
gregster	Thanks very much Nigel, and all the other guys who helped out, i'm off to learn about PICs!!! Incidentally Nigel, are those circuits you mentioned from ETI magazine still knocking about? I'd be very interested to see them even though the PIC route is obviously best for my problem.

18th February 2007, 01:13 PM	(permalink)
gregster	Well please don't spend hours rooting through on my behalf!!!! though if you should happen across them i'd love to see em Thanks again for your help, the muddy waters are clearing, bloody slowly mind!!!