control dc motor using microcontroller

[PrakashMeena]

I need to control the speed of a DC motor using micro-controller which would take input from a pressure sensor(hydraulic pressure).

I read about 8051 and it seems most widely used micro controller.
But how to configure it with the motor? All the motor has for speed control is a throttle.
Top line is my objective. Are there other ideas I could use to do the same. (Any advice is more than welcome)

 

[PrakashMeena]

other ideas, instead of using micro-controller?
basically need to control speed using pressure sensor(hydraulic)

 

[ScottyUK]

Engines have a throttle. DC motors typically have a speed controller or a switch of some form. What have you got?


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[LiteYear]

All depends on what your output needs to be. The input is easy - any ADC equipped microcontroller will probably do.

But as Scotty suggests, your output requirement is not clear. Is the DC motor brushed or brushless? Does it already have a drive attached (it sounds that way, given it has "speed control")? What sort of signal is the speed control? For example, is it an analog signal or a PWM signal?

At this stage it appears you don't need to do motor control, only speed setting. In that case the choice of microcontroller is probably of little concern. Assuming you don't have a lot of experience with microcontrollers you would be much better off picking a commercial off-the-shelf development board with the necessary input and outputs and an easy to use programming interface, rather than worrying about what processor is being used.

 

[PrakashMeena]

its a brushless DC motor. it does have a THROTTLE to control its speed and PWM signal. i would probably need 4-5 speeds based on the pressure in hydraulic pipe(lower the pressure higher the speed and vice-versa)

 

[btrueblood]

I'd think you could do the job more simply and cleanly with an inverting op-amp, a power transistor, and some resistors and other fiddly bits. Make one of the resistors a potentiometer, and you could even adjust the output gain to give whatever steady pressure was desired.

 

[LiteYear]

btrueblood is right - if you just need a discrete function of speed v pressure, and your input signal is a voltage and your output signal is a voltage (is it? Even in capital letters a "throttle" is not clear), then a microprocessor is overkill. A digital or analog discrete component circuit would be more straightforward than a microprocessor design.

 

[PrakashMeena]

i need to control speed using pressure, so this would work?
no need of micro-controller?

 

[btrueblood]

Wups. Didn't see "brushless DC" earlier, so, no power transistor. Just whatever current or voltage input the "THROTTLE" needs. If it wants a digital word for its control input, well, then, maybe you do want a micro.

 

[PrakashMeena]

which micro?
heard that 8051 is good....any advice?

 

[ScottyUK]

BTB, It's probably a pushrod linkage or a Bowden cable like most other throttles...

PrakashMeena, if you use the correct engineering terminology then you at least create the illusion that you're an engineer and not a mechanic dabbling with wires and motors.


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[btrueblood]

Thanks Scotty. I was envisioning a pair of hands wrapped about someone's throat at first...but my mind has been wandering to the dark side lately.

 

[ScottyUK]

For that I nominate the OP...


----------------------------------

If we learn from our mistakes I'm getting a great education!