Posts

1. The idea Since having a web interface is not a part of the first few spirals for my final project, I decided to keep this week’s attempt simple and more of laying down a base for potential future work rather than making a cool interface. I wanted to try Node.js just because I’ve never written JavaScript before and I’ve heard Node.js a lot. The idea is to incorporate the boards I made last week, which consists of 2 Xiao RP2040 sending MPU6050 angle data through nRF24L01, and display the received angle data on a webpage. ...

1. The idea For networking between microcontrollers, I want to send sensor data wirelessly as a test for my final project. For the final project, I will have a audio signal processing unit (most likely implemented with Teensy 4.0) that’s taking input from my bass, modifying the signal and then output to the bass amp. It will receive information from the cyber mouse (aka the random spike generator with sensors) wirelessly, whose firing frequency depends on its proximity to an object, and generates burst firing when accelerates fast enough. The spike timing will then trigger the audio effect board to modulate the bass signal. ...

1. The coin-flipping decision-making machine Full Documentation Git Repo This week, the whole CBA section is building a machine together. After many many brainstorming sessions and discussions, we decided to make this coin-flipping decision-making machine that will help you make one decision from a list of options based on coin-flipping results. I joined the MechE team, responsible for designing and making the physical components. Personally, I designed and printed the camera mount on top of the coin flipper, and helped Cyrus a bit on the solenoid holder and coin flipper funnel design and printing as well. The camera mount works fine first try, as it is very straightforward, just needed to CAD something to adapt from 1/4-20 screws to M5 screws that we’re using for the extrusions. I remembered what Jonny told me about fillet and reducing stress concentration point, and added that in the design. It’s not heavy-lifting, but it’s holding the camera in place. The humble camera mount ...

1. The design For this wild card week, it really feels like being in a candy shop as there are so many fun topics to choose from. In the end, I chose to do composites as I imagine I can make a casing for my final project’s effect pedal. A quick look at some previous years result I realized that the details in the mold don’t necessary get transferred, and it seems like it’ll work best with big, flowing curved surfaces. As a result, I envisioned a cell-shaped blob that can go on top of my components. To achieve that organic shape, I learned and tried to play with “forms” in Fusion, which is so much fun and is exactly what I was looking for. I first created a basic disc from the rotatary tool, and then free hand pull around the form to acheive the final shape that I like. ...

1. Designing a tensegrity desk For this week, we are making something big with plywood, and I decided to make a tensegrity desk just to really understand the physics of it as it has always confused me and is not intuitive. By looking at common tensegrity desk designs, I decided to base my design off this “VIVO Anti-Gravity 12 inch Tabletop” (which is available on Amazon and is $39.99). By just designing new shapes for the arms and the two boards, I should be able to maintain the structure of it while creating something interesting. The arms look like actual, muscular arms to me, and it kind of look like the two arms in Genesis. This further inspired me to make the top board like a cloud and the bottom one like a mountaing, and I envision the two arms sticking out from the cloud and the mountain. I arranged multiple images in powerpoint to create a reference image, and imported it into Fusion as a canvas to sketch my designs on it. The reference images ...

1. Designing the baord For this week, I want to learn how to detect how close my hands are to the board, and I think it’s a perfect time to try out directly measuring capacitance with a simple circuit, where nothing is covered up by a sensor. I based the board design on Neil’s hello.load.RP2040 demo on the website (Demo), and added more header pins for hooking up a LCD next week. My plan is to tie this to my final project and make this a random spiking nervous mouse module, which will increase it’s firing probability when I get closer to it. ...

1. Preparing the wax mold For this week, I have a choice of using SLA 3D printers or milling the wax block to get the mold for casting silicone. Although SLA printers are easier to achieve more complex shapes and more straightforward, and I can imagine myself using this way more often in the future, I do want to learn how to use a table top milling machine, so that’s the way I chosen for this week. ...

1. Preparing to mill the board With the PCB design from last week, I was ready to output it as a Gerbers file. I then convert it to .png and then invert the color of the edges layer so that the outermost edge is just the edge between black and white rather than a white line. This is now ready to be sent through the mod pipeline for milling. But then I was told that for our current settings in the shop, we can only mill single sided PCB so my original design with vials has to be re-routed. I then spent some time redesigning it, trying to avoid using a 0 ohm resistor to bridge across traces, but at last gave up and used one in the end. I would still consider this puzzle game a half-success since in the begining I would need to bridge across traces 3 or 4 times. ...

1. PCB Design with KiCAD I designed the PCB with KiCAD and imported the FAB inventory library for footprints. The design is based on previous simulation with WokWi on week 2, which uses a Xiao RP2040 to control a 16x2 LCD, displaying spikes that are randomly generated. It is also connected to a Pololu VL53L1X distance sensor. I plan to program it that when your hands move closer to the board, the spike firing probability will increase, making it like a real mice that got scared and show more neural activity when you get close. ...

1. Just printing something To get started, I just wanted to print something cool and mechanical, and I came across this fascinating desktop escalator design by AlexY: Functional Escalator Model Parts Printing The Result I printed with a step size of 0.15 mm using matte PLA filaments, with 10% infill. The result turned out very nice, but I am most surprised at how the whole print connected by the brim is flexible but still strong enough to hold itself. ...