How to build a motor speed control circuit

[jonathanchik]

how to make a motor

How to build a small dc motor speed control circuit with photoresistor/phototransistor but without using MCU?

Thank you.

 

[pranam77]

speed controller circuit

How to build a small dc motor speed control circuit with photoresistor/phototransistor but without using MCU?

Thank you.

Photoresistor/phototransistor for motor speed control????? :?::idea:Any special application? Please share your idea.

 

[jonathanchik]

motor speed control circuit

I am trying to make a simple path tracking car. only moving forward, turning left and right are required.
The path is also very simple. Just a black path on a white paper with 90degree turning angle.
My idea: I use a duel motor car so that the left wheel is independent from the right wheel. By using the variation of resistance of a photoresistor due to the reflection of light from the black or white colour, the left motor and the right motor is changed. Then the car can turn left/right.
However, I could only use hardware to do the car.
Moreover, I face a problem that the resistance of a photoresistor/photoransistor is too high for 2 AA battery. The current is too low such that it could not drive the motor.

Actually. i am wondering if I connect some photoresistors in parallel such that the resistance is lowered. But the power consumption is quite high.

Please help. Thank you.

 

[pranam77]

how to make a speed controller

I am trying to make a simple path tracking car. only moving forward, turning left and right are required.
The path is also very simple. Just a black path on a white paper with 90degree turning angle.
My idea: I use a duel motor car so that the left wheel is independent from the right wheel. By using the variation of resistance of a photoresistor due to the reflection of light from the black or white colour, the left motor and the right motor is changed. Then the car can turn left/right.
However, I could only use hardware to do the car.
Moreover, I face a problem that the resistance of a photoresistor/photoransistor is too high for 2 AA battery. The current is too low such that it could not drive the motor.

Actually. i am wondering if I connect some photoresistors in parallel such that the resistance is lowered. But the power consumption is quite high.

Please help. Thank you.

Nice to know that you are thinking of an idea. But practically it is not posisble to drive a motor directly by Photo diodes in series as the power consumption of the motors will be quite high as you have mentioned. The reflections fron the photo diodes must be processed by any digital circuitry or by a suitably programmed microcontroller and then connected to some motor driver Ic's which will then control the movemnets of individual motors. Just google for the key word "Path tracking robot" or "Line follower robot" which will result in numerous sites with similar ideas. Good luck.

 

[amitjagtap]

speed control circuit

thats correct
u cant drive a motor directly from photodiode or transistor.
U have to convert output of photodiode to digital output (0 - white portion, 1 - Black patch) using amplifier and then a comparator using simple opamp circuit. Then u give this comparator output to monostable multiveibrator (using 555) as a trigger. mono multivibrator output can be connected to a motor thro a high current transistor... where a DC motor can be connected to it as a load to collector pin.
Try this