Let's Make Robots!

speed control

PWM and motors

Hey guys

I have built a robot using arduino UNO as controller and a L293D quad half H-bridge as motor driver. The motors are Pololu micro metal gear motor 100:1 HP hooked up to a 10,8V battery.

I am controlling the speed using arduinos pin 9 and 11 with PWM, but it seems difficult to get even a small amount for accuracy in speed, and the robot doesn't even move at duty cycles below 25%, and it is always quite noisy.

Trolley speed control

Imagine that you want to have a kind of "automated control" for a trolley (i.e. a golf trolley). What kind of automation system would you use?

The basic requirements would be the follwoing ones:

- Trolley is stopped, you push it and it starts due to the force of the push.

- The trolley accelerates in order to reach the speed at which you're walking.

- When the trolley is having the same speed than the person walking behind it the force on the trolley handle is almost nul and the trolley runs at this speed.

finding cheap RC ESC (speed controller)

I love RC ESCs. They are electronic speed controllers that you connect to a servo output on a RC receiver or a micro controller, and they give you full step free control over a big motor in both direction. Most of the ones made for RC cars work in the voltage range 6-8.4Volts, but there are several alternatives for people who plan to run up to 24 volt motors in almost constant stall at a gazzilion amps (read robot war contenders).

But I'm the eternal cheapskate, and wants the cheapest there is.. So far I've found thisĀ 

Well, my 28x board is on its way and I have a good chassis to work with, so I will be building my first really cool robot soon. The problem I have is that the … Read more