Goal: Design a flight controller for a tinywhoop drone

Needs to have a 2amp BEC for dji o4
Needs to use the F405 microcontroller
Fits in the 25.5mm frame
One sided preferably

Design link: https://oshwlab.com/jeffreywasd/mini-fc

Other than this PCB I will buy the following to control+connect: 1. VTX - $120 2. RX - $13 3. TX - $120

Day one

9 hours Made a initial list of components bassed on https://betaflight.com/docs/development/manufacturer/manufacturer-design-guidelines.

Watched this series https://www.youtube.com/watch?v=Rv1MVkZuGbg&list=PLoPtpxJIxgnYnPrOeGHs3rdhhPgNGIYN5 1. STM32F405RGT6 2. ICM-42688-P 3. TP74333PDQNR 4. TPS61088RHLR

This should be the base for everthing, has the controller, imu, and ldo+boast Started working on the schematic

Day 2/

2 hours Researched limits for components, relized i needed to swap out the buck-boast ic for a diffrent one, used this to help find one https://webench.ti.com/power-designer/switching-regulator

Looked at commercially avalible ones made for small crafts like these, all use a smaller controller but that also requires custom firmware which is too hard to do. Still sticking with the f405. Looked into adding a onboard RX but decided not to due to the space required.

Day 3

10 hours

Initial PCB design

Problem was that i still could not fit everthing, I gave up after this, spent too long working on this design

Day 4

8 hours

Redid the design, now I made it diagonal which will fit into the frane a bit better. Was able to get stuff to fit but unable to route the traces.

Working on a newer one that a bit more clean

Day 5 and hopefully last day

7 hours Updated the design to be FULLY one-sided!!! YAY I can save like $100 by not using standard assembly.

This time, I rounded while placing components to make sure I had space. I think I used the space much more efficiently this time. Also, on earlier boards, I calculated the distance between the holes incorrectly, which messed everything up, fixed in this one.

Day 6-7

12 hours Spent alot of time reading about and finding some open-source ESCs so i can have a baseline to build off. Hard to find any that were new and open source. Make a schematic of the ESC side of the board.

Day 8

8 hours At this point, I think I have laid out this PCB at least 15 times, I still can't find a way to fit the components on.

Day 8,9,10,11

** 30 hours ** All of these days were spent working on the schematic for the ESC or laying out the board. I got it to work with a six-layer board. Next time, I might just have a four-layer board for the FC as a smd part, and then solder it on a 2 layer esc. This also allows for upgradability of the fc/esc and it allowes easy replacement if one breaks. Below is the picture of the final board.

Mini Fc