Micro Scisky: A 32-bit Open-Source Brushed Flight Controller • Hacker News Board

Re: Micro Scisky: A 32-bit Open-Source Brushed Flight Controller

#21

Post by lloyd-christmas » Mon, Nov 20, 2017, 4:30 PM UTC

dod9er wrote: post #9

When seeing the components the first thing that came to my mind was "outdated", afterwards I saw the article is from 2016. If someone is interested in a more sophisticated approach he might want to check out the RotorX Atom: https://rotorxracing.com/products/rx122diypr-atom-diy-kit-wi...

This article is about a $70 DIY open source project, and you compare it to buying a $400 snap and fly drone with proprietary software?

Re: Micro Scisky: A 32-bit Open-Source Brushed Flight Controller

#22

Post by anfractuosity » Mon, Nov 20, 2017, 5:54 PM UTC

LeifCarrotson wrote: post #17

anfractuosity wrote: post #10

Earlier quoted context omitted.

Cheers, that looks very interesting. I'm just wondering what are the main advantages of brushless vs brushed motors for quads. Do brushless let you control the speed of the propellers more easily?

Brushed motors are around 75% efficient, brushless are around 90% efficient. This has two effects: obviously, you get more flight time from your battery with a more efficient motor, but that's not the main effect. The big one is that power output is limited by the combination of how much heat you can remove (which is roughly the same, perhaps 20W) and how efficient your motor is. With a 90% motor, your 20W of heat ma…

Cheers, that's very interesting! I didn't realise there would be a difference in efficiency of that much.

Re: Micro Scisky: A 32-bit Open-Source Brushed Flight Controller

#23

Post by dreamcompiler » Mon, Nov 20, 2017, 6:49 PM UTC

anfractuosity wrote: post #10

the_real_sparky wrote: post #7

The brushed designs have been completely outclassed by the new breed of micro brushless quads. The Hoverbot Nano is one of the best examples of lightweight brushless design. https://hoverbot.io https://www.rcgroups.com/forums/showthread.php?2806620-Hover...

Cheers, that looks very interesting. I'm just wondering what are the main advantages of brushless vs brushed motors for quads. Do brushless let you control the speed of the propellers more easily?

It's very much like how cars now have electronic ignition control while older cars had mechanical ignition control with a rotating distributor. Because software controls the electrical energy inputs to the device, the timing is infinitely variable, which is generally not true with mechanical systems. Brushed motors also tend to not last as long because the internal rotating switch (the brushes) undergo constant wear. The big downside of brushless motors is that the software needs to know where the motor is in its rotation cycle at all times, but that's typically done with indirect methods (back EMF) in small motors, and with direct methods like encoders in larger ones.