I was curious to know, other than some of the redundant telemetry features on Pixhawk-based FCs like the Holybro 6C, is there any difference between them and solder-based FCs like the SpeedyBee ones? I don’t mind learning to solder, and the price difference between the two types is fairly significant. Are there certain port options that are available on the Holybro FCs that will never be available on a solder-based FC? My drone will have a companion computer attached to record and send coordinates to GCS when it detects a human body, so will I be able to connect that to the solder-based FC (which I believe would connect via the UART port on the Holybro). If so, does anyone have any suggestions on decent midrange solder-based FCs?
No
There is no difference majorly between solder based fc and normal fcs
But, most solder fc like speedybee f405 are usually having weaker processors and less sensors which can be very limiting in the future. When you buy an fc you should consider processing power and sensors and other features. Most normal fc like pixhawk have redundant sensors and more peripherals
You can connect your companion computer to a solder based fc if it has a available serial port.
Also solder type FC with H743 processors are available and specially the larger “wing” versions like Matek or Holybro offers also all kind of sensors & interfaces.
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There is nothing like redundant telemetry. They are just normal uart ports labelled telemetry and output mavlink. You can use any port for telemetry and it will normally. Conversely, you can use any telemetry port for any other purpose like gps or VTX control, etc. although you can use multiple telemetry modules if you like
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Two features I haven’t seen on as you call them soldered flight controllers are IMU heating and internal vibration isolation. Other than that they are as capable as equivalent flight controller with connectors (though F405 based ones are limited in terms of resources).
In my experience Pixhawk standard complaint flight controllers struggle with analog current sensing on planes as they have fairly high current draw on the common ground leading to noticeable current offset.
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I use both types of boards and as long as you’re buying quality parts (Matek, Holybo, Cube, etc) then you’ll be good in that regard. Feature-wise, other than the IMU heater and mounting that @LupusTheCanine mentioned, I agree they are very similar. I would argue that the “soldered” boards generally can be lighter and smaller so better suited to applications where space is limited. But I’ve stuffed the 6C-mini into some small builds with great success so it’s really up to you.
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Each can have it’s advantage in ease of building multirotor depending on the wiring setup as well.
Solder-based FC usually normally have 4-in-1 ESC connectors (and may not have solder points for the ESC signal wires) which makes integrating it with a 4-in-1 ESC compact and simple (although pinouts for the 4in1 are not standardized and may need to be re-pinned). Since the 4 in 1 ESC integrates the PDB and Battery monitoring and the Solder based FC integrates the power module, the wires that need to be soldered can be kept in one location (on the FC/ESC stack) which can allow the wiring to be compact and clean. This is what I call “FPV architecture”
Pixhawk style FCs rely on connectors which will make it basically plug and play with connectorized single ESCs and motors. However it can result in a lot of wires and connection points that will need to be managed in the drone (Pixhawk Architecture).
It is a massive pain to convert the wiring between a 4in1 ESC pinout to a single ESC servo connector and wire in the separate power module for a Pixhawk FC. It’s also a massive pain to squeeze the single ESCs and PDB wiring harness as well as a separate current sense into a 4in1 connector
Depending on the frame kit and parts you buy or wiring architecture you choose, it’s best to focus on one style or the other as it saves a lot of work of converting.
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Of particular note, the Pixhawk hardware standard requires an FMU + IOMCU co-processor, a design spec typically absent from the bare board designs. It’s arguable whether this is a desirable feature, but it is a notable difference.
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