In the APM wiki, on the page about connecting your RC equipment, there is the following comment:
If you want to have six modes, you'll probably have to configure your RC transmitter to do this. That's usually accomplished by mixing a two position switch and a three position switch on your transmitter.

However, no example is given as to how this mix might work. In the comments to this blog post Setting Flight Mode with Hitec Aurora 9 there is a method given by Juan Enrique that I did in fact get to work with my JR 9303, however, it only gives you 5 flight modes, and not 6.

For those that want the full taco, and have a Tx with both a 3-position switch and a 2-position switch, try the following mix. I've only tested this on my JR9303 but really it should be easy to translate to any other Tx.

1) Choose your two switches. For this example I am choosing:
- Flap switch = 3 Position switch (also called my Flight Mode switch on the 9303)
- Gear switch = 2 Position

2) Modify the end-point (or travel adjust) on your 3 Position switch. Instead of travelling +100/-100, you need to change it to +65/-65. On the JR radio, if you are also using the Flap switch, this will actually show as Up 65/ Down 65, but it's the same thing.

Don't mess with the end-point (or travel adjust) of your Gear switch, leave it at +100/-100.

3) Now create your mix. On the 9303 there are two types of mixes: programmable mix 1 & 2 are multi-point, 3-6 are "standard" mixes. While you could probably get the multi-points to work, don't bother, just pick one of the standard mixes. I chose mix #3.

You are going to mix your 2-Position Switch (Gear) -> 3-Position Switch (Flap). In some terminologies, the equivalent statement is that your Master Channel will be the 2-Position Switch, and your Slave Channel will be the 3-Position Switch.

Really the screenshots below will explain much better than I can in writing. Basically:

- When your 2-Position Switch is "On" (position 1), set the mix to the 3-Position switch at -17 for the 3-Position switch in the "down" position, and 0 for 3-Position Switch in the "up" position.

- When the 2-Position Switch is "Off" (position 0), set the mix to the 3-Position switch at -33 for the 3-Position switch in the "up" position, and 0 for the 3-Position Switch in the "down" position.

4) Confirm that you get the correct PWM measurements. Do this by using the convenient test mode on the APM (v2 only), accessible via the CLI. See this page for how to access the CLI: APM CLI. Once connected to your APM, type "test" then hit Enter. Next type "pwm" then hit Enter. Make sure your radio is on. You will see rows streaming by with the PWM outs for all 8 channels. If you have the standard setup your flight modes will be on channel 8. Confirm that by moving your 3-Position and 2-Position switches you get all 6 of the following PWM values, or close to it:

1815
1685
1555
1425
1295
1165

These are the ideal values, but if you are slightly off that's ok. For reference, here is what the APM is looking for:

Flight Mode #
  --  Min. PWM  --  Ideal PWM  --  Max. PWM

#5  --  1750  --  1815  --  >1815

#4  --  1620  --  1685  --  1749

#3  --  1490  --  1555  --  1619

#2  --  1360  --  1425  --  1489

#1  --  1230  --  1295  --  1359

#0  --  <1165  --  1165  --  1229

 

You can assign any flight mode to any number with one exception: Flight Mode 5 (PWM >1750) is ALWAYS manual. This can't be changed (unless you want to modify APM code yourself). The reason for this is the fail-safe.

To assign the desired flightmode to each of these numbers (except of course #5), you again use the CLI in the Setup Menu -> "modes" command.

Question: Since Flight Mode 5 is always Manual, what happens if you don't like the direction your Tx switches end up at? You can try two things:
- Use channel reversing on your 3-Position switch.
- For your 2-Position switch, you'll notice that reversing the channel on your Tx will have no effect on the PWM output. If you want to reverse your 2-Position switch, you have to modify the mix. Instead -17 and -33, change these mix values to +17 and +33, and swap their locations (from 3-Position switch "up" to "down" and vice versa). Again, see the photos below for clarification.

Question: What if my PWM values aren't exactly what you get? In this case, try adjusting the mix values. Note that if you increase one, you will probably need to decrease the other (so if you up the 17, you might find you'll need to lower the 33). The end-points also make a difference and if you want you can adjust those, but I think the +65/-65 is what you really want.

Hope this helps someone... It drove me nuts for hours.


Luke



3689401198?profile=originalTravel adjust / end-point adjust (different names for the same thing). Set your 3-Position switch to +65/-65 (here I am using the flap switch)



3689401255?profile=originalMix your 2-Position switch (Gear in this case) to your 3-Position switch (Flap in this case) and have the mix be controlled by the 2-Position switch (Gear)



3689401230?profile=originalAlternate mix if you want to reverse the direction of your 2-Position switch (Gear in this case). To reverse the direction of your 3-Position switch, just use the channel reversing function in your Tx.


3689401268?profile=originalExample output of the "pwm" test program from the APM command-line-interface. Channel 8 is showing flight mode #5 (manual).



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Comments

  • Works on my Futaba 7C 2.4GHz as well!!!
  • 3D Robotics
    Excellent! I've added a link to this in the wiki.
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