A friend once asked my help to create a mechanism that would automatically spin a wire pay-off station for coils of concrete steel bars.
This machine, an automatic stirrup bender, has two of these stations where iron coils can be placed, as you can see in the image below. The machine cannot work as intended when the iron coil is full, so a person is typically needed to assist it by pushing the coil in order for it to pull the iron until its weight can be supported by the machine itself.
An automatic stirrup bender
So my idea was to make a motor to assist the machine in pulling the coil by automatically rotating the coil station, eliminating the need for a worker to physically rotate the station.
I used spare components from old machines that I could find here and there to construct the base of the motor. I also assembled the electrical panel using spare components from old machines.
The system has a foot switch so that a worker can operate it manually or an Arduino can make it work automatically. An automatic or manual control system is required because, if the spinning wheel were to rotate continuously without control, the coil could quickly become damaged.
The electrical system is below. It has two relays, one for the motor's forward movement and the other for its backward movement, as well as thermal protection for the motor. An Arduino is in charge of everything, but a foot switch is also available for manual control.
I got an output signal from the device's motor, which I used it for the Arduino. I therefore programmed the Arduino to count how many times this signal went on and off and adjust the rotation speed as necessary using that signal.
For instance, if a piece of iron required 5 movements to complete, the Arduino would measure the first movement and, if the last movement was small, would make 4 turns forward and 1 turn backward to maintain the coil's position.
See the motor in action