OpenTx programming for single-channel

[Jean-Marie Piednoir]

OpenTx as in the FrSky Taranis transmitter is powerful enough that it can be programmed to emulate single channel operation of a servo equipped model, and, with the addition of an RC switch, drive a rubber escapement and even a pulse proportional magnetic actuator, all from a single transmitter, just by selecting the model memory.

Other transmitters hosting Opentx, such as FlySky 9x can also be programmed for single-channel

Example of the programming are given below:

1- Simple escapement (requires an RC switch on channel 1, operates from the trainer switch, cannot be simpler)

CH1 SH Weight(+100%)

2- Basic Beeper (generates one pulse with right aileron stick, two pulses with left aileron, or manually from the trainer switch as above)

CH1 CS3(L3) Weight(+100%)

R MAX Weight(+100%) ) Switch(CS6(L6))

CH2 MAX Weight(+100%) Switch(CS5(L5)) Slow(u0,9:d0)

CS1(L1) a<x CH2 20

CS2(L2) a<x CH2 40

CS3(L3) OR CS1(L1) !CS2(!L2) CS5(L5)

CS4(L4) a>x Ail 40

CS5(L5) a<x Ail -40

CS6(L6) OR CS4(L4) SHv

3- 2P2N emulation (for servo equipped models, from the trainer switch with proportional still available from aileron stick - this one for OpenTx V2.0.0 or above)

CH1 L1 Weight(+100%) Switch(SHv)

AIl Weight(+100%)

L1 Sticky SH^ SH^

More sophisticated programming has been developped, but for the moment, the above should give a useful taste of what is possible.

Single-channel rules!

[Chris Bott - Moderator]

Ooh found it - Thanks JMP

[Jean-Marie Piednoir]

4- Simple Compound escapement emulation via the trainer switch, one press for right, two for left on channel 1 and three for up elevator on channel 2, with optional simultaneous proportional rudder and elevator from the stick.

CH1 MAX Weight(-100%) Switch(SHv)

R MAX Weight(+100%) Switch(CS2(L2))

R MAX Weight(0%) Switch(CS6(L6))

Ail Weight(+100%) (option)

CH2 MAX Weight(-100%) Switch(CS6(L6))

Ele Weight(+100%) (option)

CH13 MAX Weight(+100%) Switch(CS3(L3)) Slow(u0:d0.5)

CH14 CH14 Weight(+100%) Switch(CS3(L3))

R MAX Weight(+100%) Switch(CS4(L4))

CH15 MAX Weight(+100%) Switch(SHv) Slow(u0:d0.5)

CH16 CH16 Weight(+100%) Switch(SHv)

R MAX Weight(+100%) Switch(CS1(L1))

CS1 a<x     CH15     20     SHv

CS2 a~x CH16 100

CS3 AND !CS1(!L1) !CS2(!L2) SHv

CS4 a<x     CH13     20     CS3(L3)

CS5 a~x CH14 100

CS6 AND !CS4(!L4) !CS5(!L5) CS3(L3)

 

 

 

 

 

Edited By Jean-Marie Piednoir on 09/08/2014 11:20:12

Edited By Jean-Marie Piednoir on 09/08/2014 11:21:34

[GONZO]

JMP,

I take it that the throttle is still propo on the LH stick (mode 2) if throttle is fitted to the plane? ie no 'quick blip' sequential motor control via this or some other switch.

[Jean-Marie Piednoir]

You are right (if you do activate the throttle on another channel), but mind that above are only basic examples. I'll have the more elaborate programs up for download in a day or two, they are too long to post here. Let me get them organised.

Three or four position throttle with three presses is provided for in the compound escapement emulations, I haven't done the quick-blip.

However, quick-blip is included in the full Beep Box.

Edited By Jean-Marie Piednoir on 09/08/2014 16:38:03

[Jean-Marie Piednoir]

5- Pulse proportional for magnetic actuator, with RC switch on channel 1. ( for OpenTx v2.0.0 and above)

I never dreamed this one would come about, but here it is, pretty crude and still somewhat experimental, pulse rate only about 3.3Hz. However, in flight it has proven to be perfectly practical and satisfactory. My Owen Kampen Whizard with Cox Baby Bee and Adams actuator seems to love it!

A curve is necessary for the stick input to obviate gross non-linearities introduced by the various latencies in the system (processing time, PPM frame rate, etc...)

MIXES

CH1 L2 Weight(+100%)

CH2 L1 Weight(+99%) Slow(u0,1:d0,1)

LOGICAL SWITCHES

L1 Timer 0.1 0.1

L2 a>b [I1]Ail CH2

INPUTS

[I1] Weight(+100%) Source Ail Curve(CV1)

CURVES

CV1 3pts Smooth -100,-100 : 0,+40 : +100,+100

 

Edited By Jean-Marie Piednoir on 09/08/2014 16:39:05

Edited By Jean-Marie Piednoir on 09/08/2014 16:44:07

[Jean-Marie Piednoir]

More elaborate programs are available for download:

https://db.tt/nPm5iqep

Please read the readme file for explanations.

[Chris Bott - Moderator]

Jean-Marie

I've taken one of your setups from the link above and have adapted it for my needs.

From what I could see, it was changing the throttle setting every time I applied kick elevator, so that's been removed.

So now, I have a 3 channel model working conventionally from Thr, Ail and Ele Tx sticks, with the added attraction of a compound escapement emulation using Switch SH. One for right, two for left and three for kick ele.

Many thanks for the programming, some of which I still don't understand.

[Chris Bott - Moderator]

Just realised that L11 to L16 are to do with a three position throttle, so for my setup, those have been removed now.

[Jean-Marie Piednoir]

Congratulations!

i see you are getting the hang of it.

L11 and L12 act as a divide by four counter; L13 decodes the (0,0) state to skip it.

I had programmed both kick-up elevator and three position throttle on the third button press, so that either could be used.

If both had to be used together, then throttle via quick-blip would be the best choice, leaving the three presses for kick-up elevator.

I haven't managed to do that yet, sorry.

[Chris Bott - Moderator]

Thanks Jean-Marie, I see now - you left us a choice.

My preference for throttle would indeed be a quick blip.

[Chris Bott - Moderator]

I've had a bit more of a play and this line detects a quick blip, and can be used to increment the counter.

It works well, but when combined with a proportional throttle, it requires the throttle stick to be bang in the centre when using the single channel.

So, I've now added a switch (SF) to switch between single channel throttle and proportional throttle. I've also added a sticky throttle cut to the model, for safety.

The only thing I'd like to change now, would be to have the counter reset to throttle off, every time I switch from propo to S/C throttle (so it's always predictable). Would this be simple, Jean-Marie?

[Jean-Marie Piednoir]

Resetting the single-channel throtte to idle (off) when selecting the single-channel mode should not be complicated.

I have not the time now, but will give it a look tomorrow night.

[Phil Green]

This is the most innovative example of Taranis programming ever! Excellent work, Jean-Marie.

Cheers
Phil

PS has a parcel arrived yet?

[Chris Bott - Moderator]

It is indeed isn't it Phil?

Jean-Marie, I've emailed you my eepe just in case that helps.

It includes the switch between blip and proportional throttle. It has the sticky throttle cut, and I've changed the blip sequence to:- off,half,full,off

Lots of fun this, don't worry about when you look at it, I'm in no rush at all. Just, many thanks.

I've now had a play with this with a model, and matched the servo centres to be exactly the same as my McGregor S/Ch Tx setup. I've yet to fly with it though.

[Jean-Marie Piednoir]

Phil, thanks for the compliment and the package which came in this afternoon.

 

Edited By Jean-Marie Piednoir on 04/11/2014 15:51:27

[Alex Calderhead]

Any chance we could have a Galloping Ghost emulator using two servos?

That would be something!

[GONZO]

Don't know about using the Taranis but Phil G has been working on something **LINK**

[Alex Calderhead]

I use Phil's propo and SC encoders, they are brilliant. I was just wondering if the Taranis could do it in software using two servos instead of the Rand escapement. It's beyong my Taranis programming skills.

[Jean-Marie Piednoir]

Posted by Alex Calderhead on 17/11/2014 11:53:28:

Any chance we could have a Galloping Ghost emulator using two servos?

That would be something!

I just tried the following, which is an extension for two servos of my earlier pulse propo magnetic actuator driver.

Inputs:

IAil 100 AIl CV1

IEle 100 Ele CV1

Mixer:

CH1 100 L2

=: 100 Ail SHv

CH2 100 L3

=: 100 Ele SHv

CH5 99 L1   Slow(u=0.1,d=0.1)

Curves:

CV1 3pts Smooth   -100,-100 ; 0,+40 ; +100,+100

Logical Switches:

L1 Timer 0.1 0.1

L2 a>b IAil CH5

L3 a>b IEle CH5

Note 1 : You can switch between the Galloping Ghost emulation and regular proportional control by flipping SH.

Note 2 : This emulation is at a fixed pulse rate for both channels (3.3 per second) which is about as fast as the OpenTx firmware will allow.

 

Edited By Jean-Marie Piednoir on 17/11/2014 23:05:19

Edited By Jean-Marie Piednoir on 17/11/2014 23:28:19

Edited By Jean-Marie Piednoir on 17/11/2014 23:29:36

[Alex Calderhead]

Hi jean,

I am having trouble following this part of the programming.

CH1 100 L2

=: 100 Ail SHv

CH2 100 L3

=: 100 Ele SHv

Alex.

[Calvin McCarthy]

I saw the article in the RC Soaring Digest describing how it was possible to program a single channel control emulation in the Open TX Taranis. I did not find the instructions for this at the time so this gave me a challenge. After playing around with the Logical Switches for a while I was able to come up with a simple alternating Left-Right-Left-Right Rudder like a simple escapement action. You first move the Rudder stick to one of its extremities, then return it to centre. Then using the Trainer Switch (SH) everytime you pull it toward you and hold it, the rudder will move to the side opposite to the side it was for the last control action. Releasing the switch will return the rudder to centre. Have a look. I would be interested in comments

Single Channel Rudder control

This mix creates a side to side, alternating Rudder action like a simple escapement output. The ordinary stick control of the rudder, elevator and throttle is always available as well. To start, move the rudder control (For a Radian using Right stick Left Right for Rudder) to full right or left then release it. Then pull Switch H toward you to move the rudder to the side opposite to the side you initialized it to. When you release the switch the rudder will return to center position.

Rudder Mix

1 Rud Weight (100%)

MAX Weight (+100%) Switch (L8)

MAX Weight (-100%) Switch (L9)

Set Rudder side to side distance by adjusting SERVO Min and Max

L1	|a| <x	Ch1	3
L2	a<x	Ch1	-95
L3	a>x	Ch1	95
L4	Sticky	L2	L3
L5	Sticky	L3	L2
L6	AND	L4	L1	SH-Down
L7	AND	L5	L1	SH-Down
L8	Sticky	L6	SH-Up
L9	Sticky	L7	SH-Up

1. Flag L1 is TRUE when the rudder value is centred ( |a| < 3)

2. Flag L2 is TRUE when the rudder value is -100 ( a< -95 )

3. Flag L3 is TRUE when the rudder value is 100 ( a> 95 )

4. Flag L4 is set TRUE when the rudder value is -100 (originally set by the rudder stick, but later by the alternating action). L4 is set FALSE by the rudder value changing to +100.

5. Flag L5 is set TRUE when the rudder value is 100 (by the alternating action). L5 is set False by the rudder value changing to -100.

6. Flag L6 is TRUE when Rudder is centred AND Rudder was last at -100 AND Switch SH-Down.

7. Flag L7 is TRUE when Rudder is centred AND Rudder was last at +100 AND Switch SH-Down.

8. Flag L8 is toggled TRUE when L6 is set TRUE. (+100 added to Rudder value in Rudder Mix) It is toggled False (Rudder value set to default 0 with release of momentary ON Switch SH)

9. Flag L9 is toggled TRUE when L7 is set TRUE. (-100 added to Rudder value in Rudder Mix) It is toggled False (Rudder value set to default 0 with release of momentary ON Switch SH)