madflight FC1 - RP2350B Flight Controller

[vidma]

@qqqlab Nice to see the first FC based on RP2350, congrats 👏 ! [1]
Actually since new year, I was even thinking of (and partially in progress of) designing my own, so I'd be quite interested to test it, or to brainstorm some ideas (here or info@flyuav.lt )

p.s. maybe you'd have a discount code (if such exists) for your contributors? ;)

---

couple of first quick ideas for next version:

• how about naming at least some of pads (intended to be used externally) with their default function, e.g. I2C, RC TX/RX, UART TX/RX
• AIO/all-in-one
  • maybe even embedded GPS module (not sure if good idea due to RF interference)?
  • embedded ELRS RX (or, if FCC/EU RF certification is an issue (as I'd guess), just pads in right order, like exists for DC-DC converter, to quickly solder an existing one, say from radiomaster)? which it seems are already in right order with pads 0-1 (?)

• maybe version in smaller form factor (e.g. for gliders)
• add connectors so no soldering needed (like on mamba boards):
  • GPS ?
  • digital VTX (less important/useful)

---

As a side note, my original far fetched idea was that RP2350 being cheaper than STM32 (~2$ for chip + oscillator vs dunno >7-15$ for STM32 chip) there could exist, at least in theory, a really cheap poor man's RP2350 version of FC intended for education, e.g. kids, schools, universities, etc. However, to make it really cheap that'd require, if considering say JLCPCB, PCB production at larger scales.

Alternatively this poor-man's version could be made by DIY soldering into a cheap empty basic PCB to connect those - still easier than to think what cable to solder where (so no expensive JLPCB assembly needed, and maybe quite fun for kids too). Maybe I'll finish making this one some day (soon?) myself.

• existing official Pico2's / RP2350 Tiny
• existing accelerometer boards (like 3-6eur ones from https://store.kouno.xyz/ incl the ICM-45686 one - Add IMU_USE_SPI_ICM45686 #37 )
• ELRS RX

[1] https://www.tindie.com/products/madflight/flight-controller-raspberry-pi-rp2350b/

[qqqlab]

@vidma Nice to hear back from you! I'll gladly send you a flight controller for free if you'll actually build a drone with it and publish your work on a social media site like youtube, reddit, instructables, etc. Would that be something?

My main design goal was closer to your poor man's version, and not an all-in-one version: keep it cost effective but at the same time as flexible as possible. Make it easy to add components like rc receiver, gps, radar, etc. For example, in the default config the first 2 pins are in the correct order (GND 5V RX TX) to connect a rc receiver 1-on-1, the next 4 pins are uart+i2c are for gps+compass.

[vidma]

@qqqlab sounds good, drop me an email, please.

also I'll be able to show it around at a local geeks event where I'll be telling about my work/playtime on PX4 for RP2350 (only very very partially working) - ntacamp/404.notrollsallowed.com#304 .
Could possibly make a little madflight workshop there (if anyone will be interested).

also, if/when I'd find time, I could test adapting a PX4 board template for FC1, however in PX4 there there's still a few major peripherals that do not work yet for unknown reasons - SPI, GPS, PWM - and there's a lot to do. Would you'd be interested in PX4?

also it would be interesting to hear update on where does madflight's roadmap stands in near and far future in terms of features compared with PX4/Ardupilot? What do you use it for by yourself mostly - Planes, QuadCopters?

[qqqlab]

@vidma you should have received my mail