Initial Phase
Our next idea was to use a stepper motor to control the vertical movement of the solenoid actuator. Drawing inspiration from Clarice Lee’s group (Automated Pipette), we planned to use the same stepper motor (T6 Linear Slide Stage Actuator) to move the solenoid actuator to an appropriate height to push the button.
Also, after losing many springs from our previous solenoid actuator, we bought a new kind of solenoid actuator that was a push-pull type, and the direction of the pushing/pulling was controlled by the polarity of the solenoid actuator. Details can be found in this and this blog post.
To attach the solenoid actuator to the stepper motor, we designed an L-shaped attachment where the two rows of holes will fit to the stepper motor, and the single row of holes will fit to the solenoid actuator.
Prototyping
The above photo shows Version 4 of the design specifications of attaching the solenoid actuator and the stepper motor to the fan body, which is using a C-clamp to attach the stepper motor to the fan body, and an L-shaped attachment, to attach the solenoid actuator to the stepper motor.
After a few trials, we realised that the L-shaped attachment was flimsy, and adjusting the position of the solenoid actuator was not intuitive at all, since it could only fit into the holes that were printed. Hence, we changed our design to reinforce the L-shaped attachment, and changed the holes to slits.
After all the adjustments, we also realised that our solenoid actuator was not able to push the button reliably, due to both distance and power/voltage supplied issues. Details of that failure can be found here. It was time to fall back on the backup plan of using a servomotor.