Actuated sensor, kind of

Hi there,

For a project, I have created sort of a physical timer, actuated using a stepper motor. For my application, I want to be able to adjust the timer by hand while its running, after which the arduino should know its updated position. A knob is directly attached to the motor shaft for this purpose. Furthermore, at some point, the motor should be able to block this “manual adjustment”, but still keep ticking as a timer.

The way I have currently done this, is by attaching a rotary encoder to the motor shaft via gears. I am allowing manual adjustment by disabling the coils of the motor and blocking adjustment vice versa.

A stepper motor with engaged coils is actually more difficult to move, but it is not impossible. My project should only produce a working demo but I want to get as close to the actual solution as possible.

I am really interested in any ideas you guys might have in achieving the same requirements, measuring the current position and blocking and allowing adjustment.


Copy the design of the controls used on the Peavey VIP 1 guitar amplifier. Each control is a rotary encoder accompanied by an LED display to indicate the value. Software control gives you the option of using or ignoring the user input.

The higher the motor holding torque, the more effective the blocking action.

Check the motor data sheets for that specification, and make sure that you have an appropriate motor driver, capable of the required winding current.