What exactly is 'iomixer' ?

More info: http://www.iforce2d.net/tmp/swip/overview/
https://www.youtube.com/playlist?list=PLzidsatoEzeieb0l_EUxpR0p7ed_RUPD6
The first draft of this video ended up being 1.5 hours long because it included more hands-on examples, but I decided to re-make it as a more concise introduction to the core concepts. If you'd like to see examples of setting up an nRF24 connection, display screens, logging output etc you can see the original draft here: https://youtu.be/ZeaFTIJPsBo
(start at the 10 minute mark to skip stuff that was mostly the same as this video)

00:00 Intro
00:35 What is sbusmixer
01:57 Background
04:14 Hardware overview
05:35 Device inputs and outputs
06:14 Configuration overview
07:39 'Nodes' overview
08:30 Node configuration
11:14 Connecting device to a web browser
13:08 Simple LED blink demo
15:38 Debugging with realtime values
17:19 Reading back config from device
19:58 Injecting live values
22:18 Updating firmware via bootloader
24:24 USB gamepad emulation
28:18 Sending live values to custom webpage
30:56 Diagnostic checks
31:57 Proof of concept playlist and future plans