Initial Phase

From the first progress meeting, we decided that we would need to

  1. Make the attachment more universal
  2. Retain the accessibility of the buttons
  3. Reduce the number of solenoid actuators

Hence, version 3 of our design consists of a bar that moves vertically up and down, with a housing for a solenoid actuator in the middle to push the respective button.

A screenshot of what the whole setup would look like (without the fan)

The initial mechanism of how the bar would move up and down was using chain links and a sprocket connected to a motor.

We also decided to get rid of the casing that was custom-printed to our fan, as that was not a universal design and it put a lot of strain on the buttons. Instead, we used a method similar to a C-clamp to attach everything onto the fan. The clamp would be secured with screws and screwed to printed pads with non-slip material attached onto the other side, allowing the attachment to be held up through friction.

Prototyping

We scaled some files from the internet (thingiverse) to 0.75 and printed it to test if it works, however, we faced many problems with printing the chain links, and decided to scrap the idea. Using a DC motor would also not give us the precision we required to move the solenoid actuator to the correct position. Details of our failure can be found in this blog post.