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Arduino-based mode switch

Posted by Stefan Gofferje on August 4, 2013 at 3:55am

FILE0080.jpg?width=750First, I used combinations of switches to select the mode of my APM. But IMHO, there is hardly anything more counter-intuitive and if things hit the fan, you can be sure to switch to the wrong mode out of pure hectic.

Next, I replaced a pot of my transmitter with a 6-position switch and variable resistors. That is already better, but to get to one mode, you likely have to switch through other modes. Also, without any markings, again, not very intuitive and it's impossible to see at one glance which mode you are in.

Finally, I hacked together a small board with 6 pushbuttons, 6 LEDs and an Arduino Pro Mini. The Arduino creates an 8-channel PPM stream of which channel 1 contains the data for the mode. The whole thing connects to the trainer port of my 9x. Additionally, I steal 5V from the display output of my FrSky module but theoretically, the Arduino could also be powered by the 3S transmitter LiPo. The program is pretty easy. Check the buttons and set the respective PPM value. The LEDs are not set by the buttons but by the actual value of PPM1 - just to be safe, in case e.g. the Arduino resets or something.

Here's the schematic:

APM_mode_switch_schem.png?width=750I'll attach design files for the PCB and the source code in the comments then.

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Comments

  • R. D. Starwalt August 4, 2013 at 6:33am

    Excellent idea and work! Thank you!

    All your observations are true and I too am concerned about 'wrong mode' syndrome. This is probably the cause of many bad events reported here in the community.

    I like your transmitter tray also. One is in the process of layout in my shop.

    -=Doug

  • Jasja Dekker August 4, 2013 at 6:27am

    Beatifully done, very very nice!

  • Stefan Gofferje August 4, 2013 at 6:23am

    The screen is a FrSky FLD-02. That has nothing to do with the mode switch, except that I take the 5V power from there, as I wrote.

    I made in vertical deliberately, so I can reach all buttons with my left hand without removing my hand too far from the left stick. If it was horizontal, I would have to move my left hand around or even use the right hand, which is IMHO a NoGo on a mode 2 transmitter.

  • Aleksandr August 4, 2013 at 6:14am

    More logically the button to arrange horizontally. Or with an equipment side, and names from above. That it would be quickly possible to be switched. And so a class. On the screen there will be a telemetry??

  • Stefan Gofferje August 4, 2013 at 5:43am

    No attachments in blog posts?

    Here are the files:

This reply was deleted.