Voice journaling pcb for recording the journal and LED reacts from it.
This week's HERO
Thank you so much to Kristof for guiding me what's the problem of the PCB design, how to use heating machine, how to debug the PCB. HUGE THANKS!!!✨
Basics of Milling Machine
CBA Shop Group Assignment
- For the group assignment, we characterized the design rules for our Carvera PCB milling machine. We started by reading the tutorial by our TA Quentin, then started producing a test PCB to understand the machine's capabilities. Our first run resulted in large amounts of burrs along the edges of the traces. We learned this was due to a damaged endmill and subsequently learned how to replace the bit. The machine is able to consistently handle traces down to 0.2mm.
- We also submitted our cuttiest Media Lab PCB Design to JLCPCB
Attempt 01: Wrong Mic Connection
Export the file
In KiCad, export the PCB design as Gerber files and drill files. Upload both files at the same time to Quentin's gerber2img tool to convert the copper layer, edge cut layer, and drill files into PNG images.
- For the exterior cut, I used the "Black and white" setting and checked "Fill edge cut" to create a solid outline including the drill holes.
- For the traces, I used the "Black and White" setting only.
Use Neal's modsproject with the Carvera mill 2D PCB program to generate the final G-code for the milling machine. The tool is self-explanatory. Just follow the pipeline to proceed.
After sanding the result was very clear and good, but the problem was that mic's five pins aren't connected separately. I needed to update the design.
Attempt 02: Redesign
Design
I changed the PCB design to connect correctly with the mic and ESP32S3 board.
Soldering the mic
For milling machine, you have to tighten the board strongly to make sure the pile of boards are even without 들뜸.
The milling machine wasn't good at separating the 5 routes. So Kristof suggested to use the knife to manually make the separate route.
For soldering the mic, the pins are under the mic so I needed to use the solder paste and the heat gun. The heat gun temperature was 320℃. But the temperature was so high ans started to change the color of the cooper board, so changed to 300℃
Sadly, because the mic pins are too small the route couldn't have the separate routes.
Attempt 03: Debugging
Changing the Footprint
I updated the footprint of the mic to change the distance between the pins. Now I have clear separate path!
Soldering with the heat
I used solder paste for soldering entire components.
- Place the solder paste
- Place the components.
- Put the board in the heating plate with the Flow mode. It will heat up and then start cooling automatically. I used Mini Brass Hot Plate Preheater.
- The solder paste will automatically change it's status and attach every components.
- Do extra soldering.
Appendix
Learning from Failure
- Never go on a trip in the weekend.....
- Manage the timeline!! Never think you will succeed in first attempt.
- Keep in mind for the USB while designing
- Step-by-Step debugging is important.
- Check the electricity after milling.
- Check the connection with the GND
- Check the LED light with the ardunio blinking code.
