Something like Multichannel

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wilopaan
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Something like Multichannel

Post by wilopaan » Sun Feb 16, 2020 6:02 pm

Hello all,

I'm totally new to OpenTX, and as a ship model builder I wonder if there is something like "multichannel" as supported by Graupner/SJ-Hott TX/RX systems. Multichannel means, that 8/16 switch positions are encoded into one prop channel. In this mode two long ppm pulses (as sync) and then the 8-switch positions are encoded.

Any hints?


wilopaan
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Re: Something like Multichannel

Post by wilopaan » Mon Mar 02, 2020 8:07 pm

Really no expert advice?

lshems
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Re: RE: Re: Something like Multichannel

Post by lshems » Mon Mar 02, 2020 10:14 pm

wilopaan wrote:Really no expert advice?
Ok. This makes more sense than your other post.

It sounds like impossible with lua. But opentx allows up to 16 channels on sbus, if I'm correct. There are sbus decoders available. And you can add a module to get 32 sbus channels.

tonnie78
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Re: Something like Multichannel

Post by tonnie78 » Tue Mar 03, 2020 6:38 am

I also do not see the added value of creating a multimodule functionality in OpenTx.

First of all, because there already is an option for 32 channels, but also I think if you would want to expand with external modules then I would suggest using the Sport telemetry link to transmit the additional datastream instead of mixing multiple values on one channel.


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MikeB
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Re: Something like Multichannel

Post by MikeB » Tue Mar 03, 2020 9:47 am

The problem is openTx (and erskyTx) don't have direct control of the RF link. They send control data to whatever Tx module you are using and the receiver then generates the servo pulses that may include SBUS. The SBUS data may be output twice as often as "normal" servo pulses.

Assuming what you are actually looking for is many on/off outputs at the receiver, perhaps have a look at here: https://openrcforums.com/forum/viewtopi ... =84&t=7299.

Mike
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!


wilopaan
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Re: Something like Multichannel

Post by wilopaan » Tue Mar 03, 2020 4:41 pm

tonnie78 wrote:
Tue Mar 03, 2020 6:38 am
I also do not see the added value of creating a multimodule functionality in OpenTx.

First of all, because there already is an option for 32 channels, but also I think if you would want to expand with external modules then I would suggest using the Sport telemetry link to transmit the additional datastream instead of mixing multiple values on one channel.
Is it possible to receive 32Channels with a FlySky-Ia6b receiver? And output these channel via IBUS-protocol?

wilopaan
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Re: Something like Multichannel

Post by wilopaan » Tue Mar 03, 2020 4:43 pm

MikeB wrote:
Tue Mar 03, 2020 9:47 am
The problem is openTx (and erskyTx) don't have direct control of the RF link. They send control data to whatever Tx module you are using and the receiver then generates the servo pulses that may include SBUS. The SBUS data may be output twice as often as "normal" servo pulses.
Ok, thank you. That clearifies all. So, there is no sync between the OpenTX and the RF-module, that generates the effective data-stream to the RX?

wilopaan
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Re: Something like Multichannel

Post by wilopaan » Tue Mar 03, 2020 4:47 pm

I assume, the switches of the TX are digital monitored, so there is no noise by an analog sampling or so. Then it should be possible to mix the switches togethher to produce a mixer-output that is easy to decode on the receiver side, when the channel output is digital via IBUS/SBUS.

For three 3-way switches to encode there a 81 distinct values to generate, for four 3-way switches it would be 243 values. Sounds possible, I think.

lshems
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Re: RE: Re: Something like Multichannel

Post by lshems » Tue Mar 03, 2020 5:02 pm

wilopaan wrote:I assume, the switches of the TX are digital monitored, so there is no noise by an analog sampling or so. Then it should be possible to mix the switches togethher to produce a mixer-output that is easy to decode on the receiver side, when the channel output is digital via IBUS/SBUS.

For three 3-way switches to encode there a 81 distinct values to generate, for four 3-way switches it would be 243 values. Sounds possible, I think.
Build your own switches on receiver side by a multiposition physical turn switch linked to a servo.

wilopaan
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Re: RE: Re: Something like Multichannel

Post by wilopaan » Tue Mar 03, 2020 5:16 pm

lshems wrote:
Tue Mar 03, 2020 5:02 pm
wilopaan wrote:I assume, the switches of the TX are digital monitored, so there is no noise by an analog sampling or so. Then it should be possible to mix the switches togethher to produce a mixer-output that is easy to decode on the receiver side, when the channel output is digital via IBUS/SBUS.

For three 3-way switches to encode there a 81 distinct values to generate, for four 3-way switches it would be 243 values. Sounds possible, I think.
Build your own switches on receiver side by a multiposition physical turn switch linked to a servo.
Thats a good joke!

I prefer the µC + MosFet variant ...

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MikeB
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Re: Something like Multichannel

Post by MikeB » Tue Mar 03, 2020 10:16 pm

wilopaan wrote:
Tue Mar 03, 2020 4:47 pm
For three 3-way switches to encode there a 81 distinct values to generate, for four 3-way switches it would be 243 values. Sounds possible, I think.
I make it one 3-way switch needs 3 values, two 3-way switches need 9 values, three 3-way switches need 27 values and four 3-way switches need 81 values.

Mike
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The difficult we do immediately,
The impossible takes a little longer!

wilopaan
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Re: Something like Multichannel

Post by wilopaan » Wed Mar 04, 2020 4:08 am

MikeB wrote:
Tue Mar 03, 2020 10:16 pm
wilopaan wrote:
Tue Mar 03, 2020 4:47 pm
For three 3-way switches to encode there a 81 distinct values to generate, for four 3-way switches it would be 243 values. Sounds possible, I think.
I make it one 3-way switch needs 3 values, two 3-way switches need 9 values, three 3-way switches need 27 values and four 3-way switches need 81 values.

Mike
Oh, yes: you're right.

Is the assumption right, that the switches are digital (not analog) sampled?

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Kilrah
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Re: Something like Multichannel

Post by Kilrah » Wed Mar 04, 2020 7:40 am

Correct.


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