@pavelchladek_dev

Hey guys, I am building a custom STM32 flight controller for an upcoming rocket competition. The goal is not just to fly up and fall down. I want proper telemetry - barometric pressure, orientation, GPS data, and the full flight trajectory.

For the main sensors, I went with a BMP580 barometer and an ICM-42688-P acelerometer. But there is a catch: this rocket is going to be relatively light, which means it is going to pull some insane G forces right off the pad. The ICM would just max out and clip the data. To fix this, I added an ADXL372 specifically to handle the high G launch shock and get accurate data.

Data logging was another important design decision. A lot of people in the community use spring loaded micro sd card slots. But with rocket vibrations, this slot is just asking for a mid-flight disconnect and total data loss. I stopped the SD card idea completely and added a soldered SPI Flash memory chip onboard to act as a black box. For the live downlink, I am using an Ebyte Lora module.

For parachute deployment, I am going with pyro channels instead of servos. I designed the MOSFET firing circuits with proper voltage dividers so I can safely measure the battery voltage and check the pyro continuity without dumping 7.4V directly into the STM32 pins and frying the MCU.

Today it has been a lot of work though. First off, Wakatime completely bugged. Probably because Kicads new version - v 10, automatically generates backup and history directories containing old .pro files. wakatime got totally confused by multiple project files in the same directory tree, threw errors, and refused to log my actual hours. I spent a lot of time just solving the issue, had to disable auto backups, and manually wipe the history folders just to get the tracker working again. I actually started the project on friday but then on saturday realized that I have also forgot to run kicad wakatime, because usually the programs dont require using wakatime, just journaling and then today solved the issue.

On top of that, I was looking at some reference designs online for the power delivery - TPS54525 buck converter and found some insane mistakes. One guy had VREG5 shorted straight to GND instead of connecting it with 1uF capacitor to GND and that would have instantly killed the chip. I removed that, checked the datasheet, fixed the routing, and built a diode OR circuit. So I can safely plug in a USB cable and my 2S lipo battery at the same time without blowing up my pc. I would say that I have completed the most of the schematics at this moment and would jump on pcb design.