Motor Shield question; output volts less than input volts
raymondl 2011-07-22 17:58:22 5270 Views3 Replies I'm using the 2A Motor Shield to drive a toy car. Using the existing car power supply which is 4x6AA = ~5.5v to go into the external power of the Motor Shield.
However when I measure the output voltage for the motors when I turn them on it is only about 3.5v.
The motors are too slow to drive the car well.
I am using PWM and have set analogWrite(6, 255).
The grounds are connected together.
The Arduino is powered by a separate 9v battery.
I measured the output voltage by putting a multimeter across the contacts while the motor is running.
Is it normal that the motor output voltage should be less than the input voltage?
Thanks for any suggestions or information.
Yours,
Raymond
However when I measure the output voltage for the motors when I turn them on it is only about 3.5v.
The motors are too slow to drive the car well.
I am using PWM and have set analogWrite(6, 255).
The grounds are connected together.
The Arduino is powered by a separate 9v battery.
I measured the output voltage by putting a multimeter across the contacts while the motor is running.
Is it normal that the motor output voltage should be less than the input voltage?
Thanks for any suggestions or information.
Yours,
Raymond
2011-07-25 22:55:26 Hi Raymondl,
PWM will provide less power out than what is input, since the signal is being modulated which means there must be an OFF or low cycle, this results in less power being delivered.
Why can't you use the 6V to power the Arduino? Hector
PWM will provide less power out than what is input, since the signal is being modulated which means there must be an OFF or low cycle, this results in less power being delivered.
Why can't you use the 6V to power the Arduino?
Hector 2011-07-23 01:08:53 Thanks Hector.
So does that mean it is normal for PWM even at "full" to privde less power out than is input?
I'll see if I can try the PLL.
I didn't know I could use 6v to power the Arduino. raymondl
So does that mean it is normal for PWM even at "full" to privde less power out than is input?
I'll see if I can try the PLL.
I didn't know I could use 6v to power the Arduino.
raymondl 2011-07-22 19:24:56 Hi Raymond,
You might want to try PLL style program to drive your motor, this kind of wiring and program tends to deliver a bit more power than PWM.
You could also try using the 6V to drive the arduino and 9V to drive the motors.
You can use the sample PLL sketch in the Wiki page for the 2A motor shield:
https://www.dfrobot.com/wiki/index.php?title=Arduino_Motor_Shield_(L298N)_(SKU:DRI0009) Hector
You might want to try PLL style program to drive your motor, this kind of wiring and program tends to deliver a bit more power than PWM.
You could also try using the 6V to drive the arduino and 9V to drive the motors.
You can use the sample PLL sketch in the Wiki page for the 2A motor shield:
https://www.dfrobot.com/wiki/index.php?title=Arduino_Motor_Shield_(L298N)_(SKU:DRI0009)
Hector 