Design Discussion on Zoom with Hanyang

Pre-meeting

After the Post-Progress Meeting Meeting, we came up with a few design ideas. The problem that we were aiming to solve was the manual control problem, where our initial attachment prevents the user from manually pressing the buttons. These were the designs we came up with:

1. Design #1 – Moving Bars
   • Have only 1 bar that moves up and down to push buttons, and that goes to a resting position below all the buttons (i.e. not covering anything) when not in use. This can be achieved through stepper motors and a timing belt.
2. Design #2 – Manual Override
   • Have a set of buttons at the side that you can press that will activate the solenoid actuators to press down on the button that you want.
3. Design #3 – Removable Bars
   • The bar can be removed/can slide out from one side to expose the button

We sent an email to Hanyang to ask for his feedback on our ideas, and to arrange a meeting so that we can discuss and see if we can develop the ideas any further.

During the meeting

For Design #1 – Moving Bars, these are the considerations made:

1. We can add screws to the holes at the side of the main body to attach the part that allows for vertical movement. However, for universality, we should aim to remove the C-shaped clamp center piece, which is very specific to the model of fan, and use something else to attach the vertical movement contraption to the fan. We also have to consider another way of attaching attachments to the fan, as our current way of using the buttons to hold up the load will increase wear on the button (as it was not designed for load-bearing), and may make it harder to press the buttons as well.
2. In our future designs, we can use both a clamping mechanism and a sticky surface (rubber friction pads, etc) in tandem to attach contraptions to the fan.
3. We can use a stepper motor connected to a timing belt, similar to a 3D printer’s mechanism, to move the bars vertically. However, we have to bear in mind that stepper motors are quite heavy, and to always consider the weight of things. We can also try to find lighter alternatives that will achieve the same purpose, as we do not need a stepper motor’s level of precision.
4. As a fail-safe, we can think about a manual way to shift the bars if there’s a connectivity problem between the phone and the Raspberry Pi/bars

For Design #2 – Manual Override,

1. It creates more complexity and more things might go wrong as we will need to design/code/produce a whole new set of functions.
2. We will most probably not use this method.

For Design #3 – Removable Bars,

1. Instead of sliding the bar out, which will result in wear and tear because of friction, we can think of displacing the bar upwards, similar to a retro ancient wooden door with a bar and bar holder.
2. We can also think of a bar with a pivot on one end and a bar holder on the other side, like the ancient wooden door.
3. We can also flip the bar upwards.
4. A carabiner/spring-loaded approach is possible, but it will add more complexity.

In the case where everything fails and we run out of time, Hanyang suggested that we change the use-case to something else, like an industrial use, where we have 50 identical fans and we need to activate all of them at the same time.

Post meeting

We will be going back to the MnT lab sometime next week, when our components are set to arrive. While we are there, we will have a short discussion with Tony about what kind of motors we can use for the vertical motion. In the meantime, after a short discussion over text, we decided that we will try to make a hinge/pivot on one side of the bar so that it can expose the button without having to remove the entire bar.