6 Position Mode Selection for APM with LED Feedback

3689503281?profile=originalHi All, This forum has been so helpful so I thought I would give back and contribute...
I was trying to understand how a previous poster on this forum actually did the 6 Position 2 Pole Rotary Switch Mod with LED Feedback. No where is there a write up on the HOW-TO for the LEDs but there is lots of information on the 6 Mode Selection. 

Firstly, these posts below are great and have been very helpful.  I take no credit on the Mode Selection.  I just figured out the LED part is all.  ;)

There is a DIY Post by Max Levine dated March 30,2011 and another on April 1, 2012. This post shows a picture of the LED's but no writeup to be found.
There is a DIY Post by ARHEXA doing the same thing but no information on LED's. (June 2, 2011)
There is a DIY Post by Paul Mather on DIY DRONES showing how to do this minus the LED's. (June 11, 2011)

Well, all that being said, I knew this is a MOD that I had to have and was not giving up on getting it done.

So let me show the Pictures.... and then I will explain some more.





You might be saying to yourself, why is there only 5 LED's? Good question. If you look closely there is only room on the panel in my desired location for 5 LED's.

So I had two choices : 
First, I could have a 6th Mode with no LED feedback/Indicator/Label
Second, just make a 5 Pos Switch and 5 Mode Selection with Labels

I decided to do the latter. I have limited space in my T9x as I have done many mods to it thus far. That being said, that was really the only location that made sense to me to put the LED's and I really don't think I will be using any more than 5 Modes at any given time. And yes, I made a custom Face Plate for the Switch (will explain later).

EDIT: And that when you calibrate your radio sticks/switches/pots, it will mess up your mode selects.  The following configuration will always work and never mess up by a calibration of the radio sticks.

Attached is the How-To-Guide

Here is the Wiring Diagram as well.


All the best!


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  • Recently made this Upgrade.

    But i added something to Preselect a FlightMode.

    When testing GPS Hold or GPS Mission.
    I prefer to have a button to Cut off the Mission (instead of Rotating your Selection Button)

    Didn't test it out..but it should work

  • update solution for configuring ER9x and OpenTx


  • Absolutely fantastic! I've learnt so much from this thread... Is there any chance you will be printing out PCB's in the future? I'd love to paypal some gratitude your way in return :)

  • Hello Leandro, send me an address via PM and I will send you out a PCB.  I think I have a few left.  As for the resistors and switch and such, I don't have that for offer.

  • LTMNO........ Congratulations for the initiative to share their creation with us. I very good with your setup leds. Did you still have PCB, resistors and switch positions 6 for sale or donation. I have difficulties to find this type of material. thank you

  • Thanks Simon, great informative post... 

  • @LTMNO – this could be a long post !

    Yes, the Tx is MODE 2. Because of that I wanted the mode switch to be RH accessible. I prefer to keep the throttle under control at all times.

    No, it’s not the standard P2 POT, it is a 6-position switch with a simple resistance ladder. All the resistors are 680ohm with 820 ohm to ground and 1100 ohm to +5V. All resistors are 5% tolerance but in fact the values are not that critical because the actual pulse widths obtained are tweaked by applying a curve to the outputs; curve 12 in my set-up. The pw outputs I get are shown in the Excel file.

    There is no channel associated with P2 until it is declared in the Er9x set-up. In this case the switch is associated with Ch5 as required by the APM settings.

    I did post some pictures of the installation on the old RC Groups Er9x forum but that was before it was hijacked to become the current Er9x forums. I don’t know whether it’s still available.

    Unfortunately I can’t give you a satisfactory eepe file because the current Eepe program doesn’t seem to support the  number of switches that I need – I believe Mike B might be going to change this. Instead I’ve provided this link to an Excel file which shows you all the switch allocations and mixes.

    For the LEDS, I used the strobe LEDS from Flytron which meant that I needed to re-jig the leds.ino file in Arducopter 2.9 (no point in trying to flash a LED that flashes anyway !). Most of the latter half of the code could be deleted. For me, the white LED strobes when a GPS lock is achieved; the port and starboard LEDS activate on arming.

    With regard to the voice files I did post something on the Er9x forum with details of how I put it together. Never did understand why people spent ages editing  and segmenting the raw wav  files. The 'voice' that I use is not Microsoft Anna !

    I hope that the links work OK and that this all helps.

  • @Simon, I finally got to see your video.. very nice... question...

    Why did you use the 5K Pot on the top right and not the front Panel Pot?  Doesn't that work on a different channel?

    Throttle no?  Also, it seems like you didn't have a switch in place but really just using the pot.  Is that true?  Also, I am not sure if you have a post or such on your strobes and what you have done?  I would like to read up on your config.  I see you were enabling and disabling stuff with bot-right and bot-left on the Throttle stick if you are in Mode 2.


  • Thats awesome... could you share you config file for er9x... would love to see the switch configs etc...

    I will have time now to work on my audio files... need to make a ArduCopter version.  I haven't searched around to see if one exists.

  • Hi LTMNO - I had problems with the video link, sorry about that. I've uploaded it to the 'videos' section on the left hand sidebar.

    Yes, I thought I'd seen your posts on the er9x forums - it took some time to understand the mixing to get the mode announcements but it now works fine. The great thing about this mod is that different models can have different mode choices, I just reference a different voice file in the switch assignments. I've just worked out how to give 'Armed' and 'Disarmed' announcements so I need to add that although the LED strobes confirm that anyway, as you can see.

    Cool indeed !

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