Project Development

Completed Tasks

• Programmed the simplest version of my controller automation
• Tested the program with my development board connected to all my input devices - 2 hall effect sensors and a rotary encoder - and output devices - OLED display and 2 relays
• Translate the system into KiCad diagram and PCB layout
• Constructed that system into a working low fidelity prototype fitted with a ballon buffer, modified compressor, aluminum canister, air pump, and solenoid valve
• Design and fabricate majority of my final project enclosure based on that low-fi prototype
• Tested pressure transducer and temperature probe individually for potential added feature

Remaining Tasks

• Refine the PCB boards layout
• Fabricate all the electronics
• Purchasing remaining electronic components - SOT-23 transistors, JST connectors, diode, etc.
• The enclosure back panel and internal frame structure design, which will be based on the PCB layout
• Assembling the electronics with the enclosure
• Filming, editing, and making slide for the presentation
• If time allows, adding more user friendly controller interface to the display

What has worked? What’s not?

All the things till this point has been working fine. The program works with all the components on the prototype and the enclosure turns out great.

Initially I'm a little bit concerned if the 3D printing process will take a long time. Fortunately I took a leap of faith to change my nozzle from 0.4 mm to 0.6 mm and install input shaper to my Prusa Mini. It's a game changer, it move almost scarily fast.

What questions need to be resolved?

Now the biggest question is, are the remaining tasks going to be a smooth sailing like this? One big problem we are facing in Bali is it's quite hard to source electronic components and tool spare parts like milling bits. My colleagues have been broken milling bits left and right, so at the moment we are unable to start our final project electronic production because we ran out of them.

I am a little bit concern wether I will have enough time to complete the final project in time. My electronic production experiences haven't been the smoothest so far. My design also requires some connectors which are also tricky to source here.

There's one technical question I just discover I don't know the answer yet. In XIAO RP2040 documentation it is said that their digital pins are rated at 3.3 V and not 5 V tolerant. I learned about using voltage divider and it got me thinking if I should incorporate it to all the 5 V input devices (analog and digital) I use? For example, I have been using rotary encoder powered with 3.3 V even though the component is rated at 5 V. It works fine, but some suggest that it's always better to comply with the specification. If I did change it to work with 5 V, do I need to voltage divide the CLK and DT pins?

What will happen when?

What have you learned?

• Done is better than perfect for me (a stubborn perfectionist) is probably the hardest pill to swallow. Learning about spiral development concept is also quite inspiring. I kinda apply it in my day to day job to certain degree, but never put a name on it nor strictly abide to it. Through this program, I learned how beneficial it is.
• In term of technical skill, I learn so much about electronics in this program. The eureka moment when I understand about the difference between 3.3 V and 5 V is an eye opening. That's when I start to understand many concept that was totally abstract to me before. Like how those value correlated to 0 and 1 value for the controller, why we need voltage divider or transistor when working with multiple different voltages, etc. There are still many things that I don't understand about electronics yet, but I am miles ahead compared to myself 6 months ago.
• Although I am quite versed in CAD, 3D printing, and programming even before this program, I never had much opportunity to stretch myself beyond my capability. Fab Academy gave me that and pushed me to learn more advanced stuff. Sometimes this bites me in the back though because I keep falling behind with my assignments!
• One surprising thing I learned is apparently I quite enjoy writing! Never in a million years I would imagine I will, but here I am. You can ask my instructor how many times he told me to stop writing so much. Okay I should stop writing and got to sleep now..