Control TX via Smartphone over BT / USB

ersky9x is a port of er9x for use on the sky9x board.
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wilopaan
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Control TX via Smartphone over BT / USB

Post by wilopaan » Tue Sep 11, 2018 2:04 pm

Hi all,

because I'm new to ersky9x, I have some (dumb) questions. My goal is to control some functions of the TX via an app on Android over BT or USB. This may be of interest for someone who wants to control ships/trucks etc. I absolutely don't want to use an analog CPPM-trainer interface.

I was directed to eepskye, which can control the TX.

1) Is there a protocol specification for the protocol eepskye is using? Is this SBUS? Do I have to enable this in the config?

2) Is this possible with every HW ersky9x runs on? E.g. Jumper T12?

3) Are the any known other projects addressing this use case?

4) Are there ways to directly interface a BT/serial-module (like HC-05) the the TX? (Otherwise, I would use an own BT/USB converter) .

Thanks for an hints!
And please forgive me the crosspost from er9x-forum.

Wilhelm

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MikeB
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Re: Control TX via Smartphone over BT / USB

Post by MikeB » Tue Sep 11, 2018 3:34 pm

1. Yes SBUS.
2. Yes, but in various ways. Some radios support adding a HC-05/HC-06 to get BT. You may use the trainer input socket, and pass a standard SBUS signal in to that (does work on the T12, I just tested it with a SBUS signal from a FrSky receiver). Some radios (e.g. Taranis/QX7), support receiving the SBUS signal on one of the external module bay pins (not the T12).
3. Only the "Linker" from Aloft that can pass SBUS from a receiver to the radio, as far as I know.
4. I have added a HC-05 to my QX7, and several other radios. The Jumper T12 doesn't have the internal connectivity available, so bluetooth support isn't available on that.

Mike
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The impossible takes a little longer!

wilopaan
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Re: Control TX via Smartphone over BT / USB

Post by wilopaan » Tue Sep 11, 2018 4:22 pm

Ok, that sounds very good!

So, to get it right: I can simply provide an 57500Bd/SBUS signal on the trainer jack, which is the 3,5mm jack on the top side? Or do you mean the USB connector, as the eepskye ist connected this way?

Does is automatically switch from CPPM trainer input to SBUS?

How are the values from this input processed? Do the take precedence over the gimbals/switches (ok, this should be in the manual, right?).

Thank you!
Wilhelm

P.S.: just noticed that jumped put a link from there download site to ersky9x - cool!

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MikeB
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Re: Control TX via Smartphone over BT / USB

Post by MikeB » Tue Sep 11, 2018 6:00 pm

Standard SBUS is 100000 baud (not even 115200). At present, this is the only baudrate supported on the trainer jack.

You need to configure the trainer source in the radio setup menu. You have 4 trainer profiles you may configure, then select one for use with a specific model.

Again, in the trainer setup, you define a switch (for each channel) to switch one of channels 1-4 between the gimbals and the trainer input. Other channels are configured in the mixer using the PPM1 to PPM16 values.
There is an automatic switch back to the gimbals if the trainer input is lost.

Personally, I would recommend the FrSky QX7 to the Jumper T12. You may easily add a bluetooth module to the QX7.

Mike
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The impossible takes a little longer!

wilopaan
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Re: Control TX via Smartphone over BT / USB

Post by wilopaan » Wed Sep 12, 2018 6:13 am

Many thanks Mike for this valuable information.

How strikt is the SBUS implementation in ersky9x? Do I need to obey the 14ms / 7ms pause-intervals or can there be longer intervals before it detects a lost connection and switches back to cppm?

Is it an normal or inverted serial signal on the trainer jack?

Thank very much!
Wilhelm


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MikeB
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Re: Control TX via Smartphone over BT / USB

Post by MikeB » Wed Sep 12, 2018 9:00 am

It is inverted serial (as is output by FrSky receivers). As this is software driven, it would be possible to consider using a different baudrate and/or a non-inverted signal, but I would need to provide configuration facilities.

The timeout for loss of signal is currently 1 second.

Mike
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The impossible takes a little longer!

wilopaan
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Re: Control TX via Smartphone over BT / USB

Post by wilopaan » Sat Oct 06, 2018 5:33 am

Do you know the pinout of the trainer jack? Is there 3,3V / 5V supply available?

Is it possible to use the USB-Port zu supply SBUS as a trainer input?

Thank you,
Wilhelm

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MikeB
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Re: Control TX via Smartphone over BT / USB

Post by MikeB » Sat Oct 06, 2018 3:03 pm

No power on the trainer jack.
No, the USB port doesn't handle a SBUS input. Currently, conecting to the USB when the radio is operating results in the radio appearing as a USB joystick to the computer.

Mike
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The impossible takes a little longer!

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