VAR Mixers and Aileron Differential

 Any value entry box in ETHOS with a square in the upper left can have 3 special input options assigned, Minimum, Maximum and 'Use a Source'

Use a source is incredibly powerful, it can mix pretty much anything that you can get a usable value out have. This allows adjustable differential from a trimmer, slider or pot, or multiple selectable values from a VAR mix.

I've seen two requests for multiple selectable Differential values with 2 different use cases, the first was on low rates only, the second wanted independent settings for left and right aileron. In the first case, a simple switch designation works, but the second requires use of a logical switch to select which direction is active. 

In either case, the VAR mix is pretty much identical. You do the following:

1. Setup a VAR Mix, name it meaningfully ('Ail Diff' works), assign the Output to a high channel and accept the renaming of the channel (in this example, it will be ch64)

Your default weight is whatever value you want to be the differential value when the selector (logical switch or physical switch) is inactive.
Add a weight, select your switch, add the value you want when the selector is active.

You can of course have multiple options in the list, VAR mixes are prioritized, so the top value whose selector is true will be the value sent to the channel.

Finally, go to the aileron mix, make sure you have at least 2 outputs selected (otherwise Differential won't do anything), scroll down to Differential. Long-press the value field and select 'Use a Source'. Set the Source to Channels->CH64 (Ail Diff) or whatever channel you used for your VAR Mix output. 

ETHOS Model Pictures - Pre- 1.2.6 Gotchas

 A couple notes on model pictures for ETHOS for old firmware or X18/X-Lite

1. The path on SD/NAND has changed as of 1.2.6, it's now /bitmaps/models and you will need to rename it from /bitmaps/user which was the path before 1.2.6. If your model pics all disappeared after updating, this is the issue. This is common to the X18 and X20 only, XE and X-Lite do not come with the old firmware and so do not have this issue unless you are cloning content off a radio on old firmware

2. The X18 will rescale BMP files, it won't do the same with JPEG or PNG. You need to resize manually to 188x160 if using JPEG or PNG.

Updating old ETHOS for Suite support

If you have an X20 or X20S with a version of ETHOS older than 1.2.10 then this will walk you through manually updating to get to the point where ETHOS Suite can update everything for you

ETHOS Suite makes updating your radio trivial, however you have to get to Firmware and Bootloader v1.2.10 or later before you can take advantage of this. The good news is that you only actually need to get the firmware and bootloader updated, you can use ETHOS Suite afterwards to sort the SD, Audio and Flash updates

Here's the procedure to do so:

1. Backup your SD card (copy all of it to a folder on your computer)
2. download the two zip files (for the firmware and the bootloader for your radio) and ETHOS Suite, unzip and put both firmware files on the root of your SD card, then eject the drives and unplug the radio from the PC.
3. Manually flash 1.2.6 from the Bootloader (it should do this automatically after you disconnect the radio)
4. Start the radio up, go to System->File Manager, tap bootloader.frsk and flash bootloader.
5. Install ETHOS Suite on your PC
6. Restart the radio in Bootloader mode
7. plug radio into PC
8. Do an Update All from ETHOS Suite to update your SD, Audio and Flash contents
9. rename bitmaps/user to bitmaps/models if ETHOS Suite does not do it for you
You need 1.1.4 or later to easily install the bootloader, so it's easiest to just go to 1.2.6 directly
The hard part of updating is the SD/Audio/Flash contents, this procedure lets you do that the easy way (ETHOS Suite)
When complete, you will now be able to update in ETHOS Suite for everything. 

Gotchas with Free Mixing for Throttle on ETHOS

 I've taken to using a pair of Free mixes for throttle on my electric aircraft to free T3 (Throttle Trim in Mode 2) for use as a gain control.

I also now use a Flight Mode for Throttle Cut, it is the highest priority FM (right after Default).

What does that gain me?

1. Throttle Cut is displayed on the screen when active, like any other FM. This makes it VERY easy to see if Throttle Cut is active
2. My Throttle Cut overrides all mixes to the Throttle Channel(s) due to use of the Lock mixer type. I've not tested to see if the canned Throttle Cut does the same.
3. I can use the FM to enable or lock out other functions like an SxR Self-Check mix, or landing gear.

What does it cost me:

1. Timer functionality. All 3 of the canned Throttle triggers for Timers no longer work. I use LSW's as an alternative, but they only replace two of the canned triggers, not the proportional one (where timer speed is tied to throttle position)
2. Potential Issues with creating new Flight Modes. Adding a flight mode requires editing the Throttle Cut mix as new FM's are active on all mixes by default.
3. More complex setup. I now have two mixers to maintain. 
4. Throttle cut overrides some other FM functionality, if I have to use it in flight I lose flaps/gear/etc. 

My Biggest Frustration with ETHOS - Trims

 If there's one spot where ETHOS is truly limited, Trims are it.

The actual Trim configuration to use Trims as intended is just fine. In fact it's pretty good and given you can do custom trim steps, doing things like 3-position trim is actually pretty easy. From a pure trimming perspective the only things missing are Instant Trim (ie sticks to trim) and Trim to Subtrim.

The problem is that when you want to use rarely-used trims for anything else, ETHOS makes it VERY difficult.

There's a couple reasons for this.

The first is a shared issue with the pots. Only the Trimmers and Pots (S1/S2) have silkscreened labels on an X20. However NOWHERE in ETHOS are those labels ever used. You can at least rename the Pots in System->Hardware->Pots/Sliders Settings (and I have), but the T1-T4 labels for the trims are used exactly nowhere in the OS. That's just silly. The switches aren't labelled on the X20, but use standard naming while the trims and pots are labelled and don't use the labeled names.

I fly electric and sailplanes, so my Throttle trim is essentially never used. I don't really use rudder trim as a trim either (I always try and center the rudder with Subtrim).

That said, I have a number of use cases for those trimmers. For one, I'm getting sick of constant twiddling of S1 every time I switch models to get gain correct for my stabilizer. That will be the standard application of my throttle trimmer/T3 for now. Flap-Elevator mix adjust will be the sailplane equivalent. For the rudder, Aileron Differential Adjustment is the desired use case.

There is NO way in the canned surface mixes to disable trim. That means if you want trim disabled, you need to disable it in the Trim menu. When you do so, you can no longer get any movement from that trimmer, rendering it useless.

So what to do?

The short answer is I'm going to be replacing my Throttle canned mix with a pair of Free Mixes. Where needed, I'll do the same with Rudder so I can abuse the Rudder trimmer to control Aileron Differential et al.

For the Throttle mix.

The first is very simply mixing Throttle to the Throttle channel(s). Absolutely nothing fancy there.

For throttle cut however you have two options.

1. A 2-point curve added to the throttle mix with both points at -100, and triggered by your throttle cut position

2. A second Free Mix, with source Minimum, Active Condition of your Throttle cut position (or Flight Mode in my case) and type 'Lock'. Again, Output to your Throttle Channel(s). 

I use the second, as the Lock type is an override, nothing will activate throttle when that mix is active.

Now I can re-assign my gain channel input to the Throttle Trim (and argh, it should be Trims->T3)

The good news is that since Free Mixes can target multiple channels, you don't have to do a mixer pair for each channel in a multi-throttle setup.

Multi-Engine Throttle in ETHOS

 Just ran across somebody having an issue with Throttle Cut and multi-channel throttle mixing on another radio OS with VERY limited multi-engine support.

On ETHOS, this is quite simple to do.

To get multi-channel throttle, go to your Throttle Mix, set your Channels Count to 2 or higher, then set each channel’s target output below (such as say Ch7 for your second motor). Up to 4 channels are supported per Throttle Mix. Clone your Throttle mix if you need more. 

Yes, you can have enough Throttle channels for a B-36 (6 turning, 4 burning. Or more likely 2 turning, 2 burning, 2 smoking, 2 choking and 2 generally unaccounted for)

Throttle Cut and/or Hold will still work correctly across both channels.

You can target those channels independently with Free Mixes if you want to have differential throttle for steering or tuning (S1 and S2 would make good tuners for a twin on gas/glow where you want to sync the two motors. T5/T6 would be even better if you have an ETHOS radio other than the X20(S) which lacks those two trimmers) 

Flap to Elevator Compensation in ETHOS

The Flap to Elevator compensation mix causes a lot of grief in ETHOS, for one simple reason.

If you use the Flaps control as your source and you apply any sort of slow up/down on the flaps, your compensation reacts faster than your flaps do and you cannot apply a matches slow in the compensation mix.

The solution is equally easy thankfully.

Don't use the Flaps control (switch/analog input), use the flaps channel as your source.

Then the compensation mix will follow what is being sent by the Flaps mix. It will also follow any other mixing you do to flaps though, so be sure to disable the compensation mix in any situation where full-span ailerons are active.


One caveat here, DON'T set your flap endpoints in the Flaps mix, set them in Outputs. Using Outputs gives you a few things.

1. It's much easier to balance multiple channels by using a 3-point curve on your reference channel (the one with the more limited physical throw if such exists) and either a 3 point or a 5 point curve on the other channel(s). Use a 3 point for the matched channels if using a 3-pos, a 5 point if using an analog input (like spoiler stick for a sailplane).

2. This lets you have a normal set of flaps settings, then an 'over flap' if you have an aircraft which has tons of flap throw, but doesn't normally need this. I will be using this on my Valiant 10cc, which has ~80 degrees of flap throw but doesn't need more than 60 degrees when landing, the extra throw will be tied to an Airbrake mode for controlling speed when diving. 

VAR Mixers - ETHOS's Unsung Innovation

One of the challenges many have had with ETHOS is there's no simple way to get a series of fixed values in a Free mix that are selected by a switch. This was fairly easy to do on OpenTX, although never as easy as it should have been, leaving many (including me) mystified as to how to do it right.

As it happens, the answer was there all the time. It's the VAR mix.

What the VAR mix does is VERY simple.

You have a default value, followed by a set of alternate values triggered by a condition (switch, logical switch or flight mode) that are in priority.

You have an output channel.

These values are in a priority cascade, so the top value whose condition is Active will be output on the channel. The channel can be either a virtual channel (not assigned to any function in the aircraft) or a functional channel (assigned to a function in the aircraft.

Note that Mixer weights in ETHOS can come from a channel value, so you can use a VAR channel as this. This is most useful for a Free Mix which can have multiple curves but only one set of weights. 

To make this even more useful, any Weight has two extra options - 'Use a Source' which allows any valid input source to be used, and if selected, you get 'Convert to Value' which lets you save the source after adjusting. This allows a VAR mixer to become an input selector and also to be used to save values after tuning with ease. 

Right now there is one thing still missing, which is the ability to easily alter the current active value in a persistent fashion. 

Making TANDEM/TWIN Function Switches more useful in ETHOS

 The TANDEM and TWIN radios have 4 or 6 Function Switches rather than the 6-position knob that the Horus radios come with.

These Function Switches can be set up one of 5 ways on the TANDEM's (I don't have a TWIN radio yet to see what the 4 switch configurations are)

6-pos with OFF
6-pos
2x3-pos
6x2 pos
Momentary.

However they CANNOT be used as sources. I'm going to go over how to get around that limitation. This is most useful for those looking to replace the 6-pos knob as a way of controlling FC Flight Modes, but there's a laundry list of other uses which effectively give you between 1 and 6 extra switches on your radio.

The solution, in short, is a VAR mix. Just one, although you can have multiple sets if you really need them. I'll go over that last, as there's 2 ways to achieve it and neither are obvious as VAR mixes cannot be enabled/disabled unlike other mixes so you cannot have 2 VAR mixes outputting to the same channel, selected by switch or flight mode. 

In short, what you do is the following.

We'll do this for the 2x3-pos configuration, as that covers the logic for all of them.

Create a VAR Mix, Name it 'Left FSW'
Add a new weight, tap the '---' box that opens up on the left line, press FSW2 (the middle left button), then set the weight to 0
Repeat that with FSW3 (the bottom left button) and set the weight to -100

Select an empty output channel, I've picked Ch64 in this case, then let it rename the channel.

Now anywhere you want to use the switches as an analog source, use Ch64 instead. It's even conveniently named for you to remember.

For the right switches, just do another VAR mix named 'Right FSW' and targeting a different channel (say Ch63). You can actually clone it to reduce time.

In terms of the number of lines you need, it's one less than the total positions, so:

6-pos with off - 6 lines total, one for each button
6-pos - 5 lines total, one for each button except 1 or 6 (your choice)
2x3-pos- 2 lines total
2-pos & momentary - 1 line total (remember to hold down the momentary when exiting selection so it does not reset)

Now for the hard part, how to have Multiple sets. 

There's two ways to do this, and both are kind of stupid. 

First off, create the second VAR mix by cloning the first one, renaming it to be clear, adjusting the values and setting a different output channel. By cloning you ensure you are using the same table selectors (ie the FSW buttons in this case).

Then you need to make the new mix override the old one.

The first and easiest is to add 1 Free mix per VAR mix over 1 you have. 
Set the source to the channel of the new VAR mix/value table
Set the active condition to the control you are using to select the VAR Mixes/tables (this can be any switch or LS, for Flight Modes leave the Active Condition as Always On, then edit the FM table for the free mix to select the FM's you want that one active on). 
Set the Function Type to Replace
Set Output1 to the channel of the base VAR Mix/table.

The second method is a bunch of dumb, but it works. That's to make a set of Logic Switches that are true on FM/selector position and table selector position (ie an example would be FM1 AND FSW3), then add those as additional table entries on the VAR mix. I don't recommend that solution unless you are running into issues with a lack of channels available for mixing, which is unlikely even on complex setups.

Getting Fancy with the SR's and ETHOS

 Someone asked about how to handle the bad logic necessary to access the Hover and Knife Edge modes on the SxR and SR series. These modes are available if you are NOT using Quick Mode on the receiver. Personally, I recommend Quick Mode. 

They wanted stab modes on SC and push button access to Hover and Knife edge modes using the rear buttons. This is what I came up with:

OK, this takes 6 Logic switches and 2 VAR mixes.

First off are two Sticky LS's, to turn Hover and Knife Edge on and off.

They're both setup the same way, note I have SCmid assigned to rates stab and SCup to Self-level in this example (slightly different than the provided example, but it gives self-level if you accidentally disable hover or knife edge modes

Sticky SIdown SIdown Act:SCup
Sticky SJdown SJdown Act:SCup

Name one Hover and the other Knife Edge

Next is one which Determines if either of these are active

Name it 'Special Act'

LS:'Hover' XOR LS:'Knife Edge

Next are two to ensure you can't flip accidentally between Hover and Knife Edge

Name the first 'Hover Act'

LS:'Hover' AND !LS:'Knife Edge'

Name the second 'KE Act'

LS:'Knife Edge' AND !LS:'Hover'


These will be active only when one of those two special modes is engaged, but not the other.

Finally there's the regular Self-level mode

Name it 'Self-Level'

SCup AND !LS:'Special Act'

This one will be true when the other two aren't and SC is up.

Now we use two VAR mixes.

The CH10 Mix has a default weight of 0
The next weight is triggered on SCMid and is 100
The next is triggered on LS: 'Self-Level' and is 100
The next is triggered on LS:'Hover Act' and is 100
The last is triggered on LS:'KE Act' and is -100
Output is Ch10

The CH11 Mix has a default weight of 0
The next weight is triggered on LS:'Self-Level' and is 100
The last weight is triggered on LS:'Hover Act' and is -100

You could simplify the Ch10 VAR mix with an additional Logic Switch, but it becomes harder to compare to the logic table in the SRx/SxR docs. If you want to drop self-level and have rates stab on with SCup and no regular self-level, delete the self-level lines on both mixes (and the Self-Level LS) and change SCmid to SCup on Ch10.

Programming ETHOS for the Archer SR Receivers for a conventional plane

I'll be covering how to setup the radio side of setting up the SR series receivers here. I'll go over receiver setup in a separate post. I'll also address Delta and V-Tail mixing another time.

First off, a couple things to cover on the receiver side because they significantly impact how you are going to program the radio.

1. Mixing. The SR series do internal delta and v-tail mixing. They DO NOT mix dual channel ailerons or dual channel elevators, although they can support both functions. You need to program delta and v-tail setups as conventional 4ch models on the radio, but dual-channel ailerons and elevators must be programmed at the radio.

2. USE QUICK MODE. the Archer SR series default to Quick Mode. Quick Mode doesn't support Hover Mode or Knife-Edge Mode. You probably don't need Hover Mode and Knife Edge mode only does one orientation and it's useless as a result. Plus the mode switching logic for these is nutty and requires a lot of in depth switchology to get usable switch setups from the crazy bad mode table. I'll only address Quick Mode in this post.

This post is going to cover how I program a standard aircraft with an Archer SR receiver. The dual elevators logic will be the same as dual ailerons.

First off we are going to create a new Model, and set it up as a standard 4 channel aircraft. Select 2 ailerons if you have/want dual channel ailerons.

The second step is to ensure the channels are mapped properly. If your default Channel Mapping is not AETR, you will need to remap the 4 basic channels

Make sure the channels are mapped as follows, by going to the Model->Mixer page and editing each mix and changing the Output channels for each mix if they don't match the following.

Ailerons->Ch1
Elevator->Ch2
Throttle->Ch3
Rudder ->Ch4

*Note if you are doing dual-channel ailerons, the right aileron must be on Ch5. Right Elevator must be on Ch6 if doing dual-channel elevators. These channels are hard coded at the receiver for stabilization.

How I do this is as follows. Note I have traditionally used TAER (JR/Spektrum) mapping as my default.

So I do this.

Edit Elevators mix. 
Set output channel from Ch3 to Ch7. Swap configs, accept channel name change. This clears Ch3 to be re-assigned without losing a channel name.
Edit Throttle Mix. 
Set output channel from Ch1 to Ch3. Swap configs, accept channel name change.
Edit Ailerons Mix.
Set output channel from Ch2 to Ch1. Swap configs, accept channel name change.
Edit Elevators mix. 
Set output channel from Ch7 to Ch2. Swap configs, accept channel name change.


Next, edit the Throttle mix, enable Throttle Cut, set the active condition to your preferred 'throttle disabled' setup, I use SFup on the X20. This is important later.

Now back out to the Mixer page

Hit the + to add a mix, select Free Mix, select Last Position
Change the name to Gain
Set the Source to Pot1 (or your preferred analog gain input)
Set the offset to 50%
Set the Weight Up to 50%
Set the Weight Down to 50%
Set the output Channel to Ch9, accept the name change offered

Now back out to the Mixer page

Hit the + to add a mix, select Free Mix, select Last Position
Change the name to Stab Mode
Set the Source to SB, or your preferred 3-position switch to control Stabilizer Modes
Set the output Channel to Ch10, accept the name change offered

Now back out to the Mixer page

Hit the + to add a mix, select Free Mix, select Last Position
Change the name to Panic
Set the Source to SH (or your preferred momentary for emergency self-level)
Set the Active Condition to SFdown, or the opposite position of the switch used for throttle hold (ie this mix will only be active if the throttle is active)
Set the output Channel to Ch12, accept the name change offered

Now back out to the Mixer page

Hit the + to add a mix, select Free Mix, select Last Position
Change the name to Self-Check
Set the Source to SA (or your preferred and otherwise unused 3-pos switch for self-check. this MUST be a 3-pos)
Set the Active Condition to SFup, the same condition Throttle Hold is active in (this will only be active if the throttle is disabled, to prevent self-check in the air)
Set the output Channel to Ch12, decline the name change if offered.

Now go to System->Hardware->Switches Settings and set the Switch middle detect delay to 0ms or Self-Check won't work.

For flaps, be sure to select your flaps configuration when creating the new model. Note that if your flaps are going to be on ch5 and/or 6, there is receiver configuration required,