Synchronizing Stepper Motors

Advanced Topic Skip if you’re new, explore when you’re ready.

Big idea

Stepper motors need a process to be homed or “synchronized.” This is a process by which the desktop app and the Bottango firmware work together to get the stepper motor to a known “home” position before it is able to be animated.

When you set a stepper motor to live, unlike a servo which goes to a green “ready state”, a stepper motor will go to a yellow “needs work” state, and show that it needs to be synchronized.

Click the Synchronize button to begin synchronizing the selected stepper motor.

While synchronizing, you have the option to manually step the selected stepper motor 1, 10, or 100 steps in either a counterclockwise or clockwise direction. Your goal is to move the stepper such that it is in the “home” position, which is the position the motor should be in at rest.

Home position is the value that the stepper will be in “at rest.” If you think back to when we created structure, we did so in its home position and rotation. When Bottango moves and rotates joints, it offsets the joint away from its home position and rotation, and then returns back to that home position and rotation when at rest. When you are synchronizing a stepper, you need to move the stepper manually to that same position. All movements once synchronized will be from this starting point.

Press the blue “Mark Synchronized” button to mark the stepper synchronized and finish setting it live.

Auto Synchronizing a Stepper Motor

In addition to the options to manually synchronize a stepper motor by a specific number of steps, if your hardware can support it, you can auto synchronize a stepper motor. Click either the “Auto Sync Clockwise” or the “Auto Sync Counter Clockwise” button to begin stepping the stepper motor in the given direction. The stepper motor will continue to step continuously in that direction until a pre-programmed hardware stop or limit switch is activated.

In order to support this functionality, your stepper must have some kind of readable limit switch or hardware stop, and you’ll need to update the callbacks file in the Bottango firmware.

Auto-synchronizing motors will move by default at 1/2 max speed, but that is configurable in the hardware driver.

If you want to run your stepper motor and auto sync it in exported animation mode, you’ll need to provide additional logic into the Bottango firmware to meet your specific requirements.

Resynchronizing a Stepper Motor

If for any reason, the stepper motor loses synchronization with what’s in Bottango, you can click the “resynchronize” button. This will mark the stepper as not synchronized, and allow you to begin the synchronization process on the stepper motor again.

As well, if for any reason a stepper motor goes not live after being synchronized, it will require resynchronization before it can fully go live again.