# arduino PWM

Hi, im still new to using arduino. I have a question, i have a code that simply moves a arduino kit car forward and backward. I set the PWM to 255 which is the maximum and the car moves very quickly. I would like to know if theres a way to mesaure the speed without using an encoder or atleast get know a way to get the frequency from the PWM so i can calculate the angular velocity. Thank you

Sa3eedo: frequency from the PWM

Frequency of what? The PWM's frequency is documented, for example here.

But however you estimate the speed, that's no substitute for measuring it: you might for example be on a slippery surface with lots of wheelspin not being translated into motion.

PWM frequency is fixed by the pin. PWM duty cycle (ratio of on time to off time) is what determines motor speed.

There is no relationship between PWM frequency an motor speed. And if you set the PWM value to 255 as you wrote, there is not even a modulation on the pin, it will be constantly HIGH.

Sa3eedo: Hi, im still new to using arduino. I have a question, i have a code that simply moves a arduino kit car forward and backward. I set the PWM to 255 which is the maximum and the car moves very quickly. I would like to know if theres a way to mesaure the speed without using an encoder or atleast get know a way to get the frequency from the PWM so i can calculate the angular velocity. Thank you

Angular velocity of what? The wheels? Speed is distance / time and the wheel has circumference distance.

PWM pulses power with zero to full strength pulses, you don't get more than all the time 5V (is 255).