12. Machine Week¶

Group¶

My group for machine week consited of Amalia Bordolio and Elle Hahn. For our machine we made a Whack-A-Neil machine. I worked on getting the Neils to go up which involved using push pull solenoids

My Contribution for Machine Week: Head Movement Control and PCB¶

My focus on the machine was to get the heads to move and to put that head movment on a PCB. This week included a mix of Arduino and KiCAD for me as I went through the designing, coding, and milling process of the electronics.

Solenoids:¶

For my contribution during Machine Week, I focused on controlling the movement of the heads. To achieve this, I first tried to use push-pull solenoids connected to a relay, which would hae enabled the heads to move up and down.

The first challenge I faced was understanding how to hook up the solenoids to be controlled by a microcontroller, as the solenoids only had a positive and negative wire. During my research, I came across a tutorial on Newbiely, which explained how a solenoid could be controlled through a relay. The tutorial showed a setup with one solenoid connected via a relay with only a single port, which initially concerned me.

However, at the Fab Lab, we had relays with four terminals. Although our original plan was to use five solenoids, it turned out that running all four solenoids from the same relay provided a much cleaner solution for both wiring and electronics.

This first attempt at the mole mechanism fell short though since I didnt realize how short the solonids actually pushed up so I had to come up with a new idea.

Servos:¶

Servos felt like the best next course of action cause I had used them a lot in the past so coding and milling would be alot easier for me. After searching with the help of ChatGPT I found something called a Rack and Pinon mechanism. Heres what that looked like:

And the pushing mechanism in it that was looked like it would send the moles high enough looked like this:

I printed it out using PLA+ and then used hot glue to press the servo to the gear and then the servo to the box. Once I had that, I was able to set up a code using the touch sensor that Amalia set up to test the new pushing mechanism. Heres what that looked like:

And heres a video of it working:

While this isnt the desiered end goal of the design, I was proud of how high the push mechanism went and how fast the servo responded to the touch sensor. Overall this part of the project was very enjoyable for me even though I had to switch the push mechanism after putting a lot of reaserch into it. One more thing to note is that becuase of how many servos we were going to use, I found an external power supply for the servos that could supply enough amps for all the servos.

PCB¶

To make the PCB for the week, I imideatly knew that it needed to be double sided. This was mainly due to my recent expierience with my final project and my nessecity for 4 servos on one board. It wasnt all bad though since I did need to have all the electronics share a common ground so that was a clear beneift of the double sided design. The first thing I did was go back to my documentation from the past week and rembered how to make the double sided board. Afterwards, I made a quick sketch to see how I was going to wire all the electronics on the board. This was espcially important becuase I had to put on the board the following electronics: 5 servos, 5 touch sensors, 1 XiaoESP32C3, and 1 place for the external power supply that would power and give enough amps to the 5 servos. This is what that sketch looked like:

From their I went to KiCAD and made the design based off my drawing. In the schematic editor, I added all the componets in the form of pinheaders besides the ESP32C3 and labeled all of them. This was crucial since the servos and touch sensors both needed 3 pinouts so I had 10 1x3 pin header footprints which would be confusing if I hadnt labeled them. From their I set the pinouts to each of my sets of pinheaders for the digital pins, then I set the touch sensors to be powered by the 3v3 line and had the servos powered by the pinheaders that represented the external powersupply. Finally I made sure that all the componets shared the ground. One thing I added that isnt on my sketch was a 1x1 throughole pinheader connected to the GND of all the componets, the external power supply and the ESP32C3. This was nessicary becuase its what allows me to make the board through hole. This is what it looked like in the end: