Arming and modes on 1 channel, what the fuck!?
No word of a lie, the night before leaving for the Weston Park Model Air Show, the idea got in my head that having the arming switch on it's own channel is a complete waste of a channel. This is 2018, why have only 1 function on a 1 channel; after-all, you don't care about flight modes if the model is not armed! This kept swirling around in my head all night, so much so that I had to get up early and try to figure it out, to the point where I left my house 20 minutes late, oops! Still, I worked it out and confirmed it today on my Taranis and iNav setup for my S800 builds.
The idea is that all the time the model is disarmed, no flight mode preference is sent to iNav, and it uses a default flight mode (manual). This does not effect the switches you use for arming or flight modes, just that instead of using Ch5 for arming and Ch6 for modes, for example, Ch5 would do both. As soon as you arm, iNav not only knows that you're armed, but also which flight mode you want to be using. So simple, and frees up a channel. It's pretty much a combination of my Throttle Cut with Safety Arming and 5 Modes Using 1 Channel tutorials, with an extra special function added.
Step 1 - The arming mechanism
As I mentioned earlier, this is the same as my Throttle Cut with Safety Arming tutorial, but as a quick recap...
- Add a 2 point Curve called Cut with values of -100 and -100.
- In Logical switches, add the following (assuming SF is your arming switch).
L01 | a<x | Thr | -98 |
L02 | OR | L01 | L02 | SF↑ | 0.0 | 0.5
- In Inputs, double click on the Thr input and set the switch to L02.
- Duplicate the throttle input and double click on it, set the switch to !L02 and the Curve to use Cut.
- In Special Functions we'll add some feedback by adding.
SF1 | L02 | Play Track | Armed
SF2 | !L02 | Play Track | Disarmed
Next we add the modes stuff, but we will add another Special Function for the arming later
Step 2 - Adding the flight modes
This is fairly similar to the 5 Modes Using 1 Channel tutorial, however the output to the channels in the Special functions screen is different.
- Go to Logical Switches and add the following.
L04 | a>x | SA | 50
L05 | a=x | SA | 0
L06 | a<x | SA | -50 | SB↑
L07 | a<x | SA | -50 | SB-
L08 | a<x | SA | -50 | SB↓
- Go to Flight modes and set up the following names with the corresponding switches.
FM0 | Manual
FM1 | Horizon | L05
FM2 | Alt Hold | L06
FM3 | Loiter | L07
FM4 | RTH | L08
This is where things change a little from the previous tutorial.
- Go to Special Functions and add the following functions.
SF4 | FM0 | Override CH5 | -33 | ✔
SF5 | FM0 | Play Track | fm_manul | x1
SF6 | FM1 | Override CH5 | 0 | ✔
SF7 | FM1 | Play Track | fm_horiz | x1
SF8 | FM2 | Override CH5 | 33 | ✔
SF9 | FM2 | Play Track | fm_ahold | x1
SF10 | FM3 | Override CH5 | 66 | ✔
SF11 | FM3 | Play Track | fm_loitr | x1
SF12 | FM4 | Override CH5 | 100 | ✔
SF13 | FM4 | Play Track | fm_RTH | x1
Step 3 - Final settings
- In the Outputs page, edit channel 5 and set the label to A-Modes for clarity.
- Go back to the Special Functions page and add this final function. It is highly important that this function is AFTER the mode switching functions, it may even be worth adding it as the last function allowed.
SF14 | !L02 | Override CH5 | -100 | ✔
That's everything set in the Taranis, now for the iNav configuration.
I've re-arranged the modes on the screen to make it easier to see how it works and how you set it up. The first thing you want to do is make sure that Arm, Manual, Horizon (or Angle if you prefer), Nav Althold, Nav Poshold, and Nav RTH are all set to use CH 5. On the Taranis, arm the model and set the flight mode to Manual. Set the slider on the Arm mode so that it starts just before the position marker and ends at the far right hand side. The Manual mode should start on the far left side and end just after the position marker. This setting means that the model will be armed for all flight modes, and when the model is disarmed it will be in manual mode. The rest of the flight mods are set up as normal. Below I have added some images to help show the position markers for the different modes.
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