Telemetry Relay

[GTiDon]

Brains needed. Please dont point me to that 3000 page rcgroups thread.


As researched I am building a box with a frsky diy TX module that is fed ppm data from a receiver. So I can place this on a pole with a booster and a good antenna. For increased FPV range. This system is tested and proven working.

But now I want to feed the telemetry data from the TX modulE in the box to the rx in the box which will give me telemetry on my radio.


How can this be done? I believe it is possible.

[jhsa]

This is a shot in the dark, But maybe use the serial ports on both module and receiver? so, TX from the DHT serial port to the RX on the receiver serial port? Ground should already be connected by the power supply?
So, the plane will send the telemetry to the DHT in the box, this will pass it to the receiver, and this will send it to your radio..
But wait before you try it. Let's see what other people have to say about this..

João

P.S. - I'm assuming that your radio is bound to the receiver in the relay box and the aircraft is bound to the DHT in the box.

Question, do the module and receiver serial ports use the same logic level? or would it need convertion?

[Kilrah]

Won't work, cause the TX module adds some framing bytes to the received stream. If you "chain" the modules then the framing will be added twice, so the radio won't understand it.

[jhsa]

Well, it sounded logic to me.. but obviously there are other variables involved that I didn't know..

[cre8tiveleo]

BT module on the tx module, BT the data to a pc or android device. Good for 30-50 feet of data transmission.

[GTiDon]

BT module on the tx module, BT the data to a pc or android device. Good for 30-50 feet of data transmission.

This was my fallback option, if I could not do the above,, I really like having the signal strngth showing on the radio.. and less things to setup when flying.

Also the thought was to have the relay box about 50m from where I would be standing in a nice open area

[cre8tiveleo]

You can get modules with better signal strength, not for the $5 ebay ones, but some other variations. Sparkfun had a few options.
Bt receiver on the tx?

or even some wifi tx/rx setup, you'd get 50m with that. just throwing ideas out there.

[GTiDon]

mmm so would the assigned bluetooth port on the sky9x board be able to receive this data or would you need a second bluetooth module on another com port. Then ERSky9x firmware would need the option to choose your telemetry data source port.

[cre8tiveleo]

it could handle data in if the code supported it. if it did, other bt enabled txs could send data to each other... ooo the possibilities then.

Using Tapatalk on my Playbook

[GTiDon]

Maybe use a device inbetween to resample the protocal.. I would really like to get this working.

How can we point Mike to this thread I think he knows the FrSky telemetry protocols very well, let me know if this is possible or not?

[Kilrah]

Of course you could put an arduino inbetween the 2 modules to strip out the framing bytes...

[GTiDon]

Of course you could put an arduino inbetween the 2 modules to strip out the framing bytes...

Thats what I was thinking, but I cant program that. If this can be done or has been done before I definitely wont be the only person using this principle. Others are already using the "relay" box as is..

[jhsa]

Yeah, this is a very nice feature for FPV users.. There are some people here able to program arduino. Sadly, I'm not one of them, yet..
Maybe someone jumps in.. It doesn't seem to be a very complicated project, but who am I to say that? My logic is not the true logic after all.. very far from it

[MikeB]

I don't think the arduino will do everything you require.
The HUB data is packaged as data in a USER frame, but the A1, A2 and RSSI bytes are in their own framed packets.
Yes, you could strip off the framing of the HUB bytes to send them on, and they would be received by er9x etc. correctly, but you cannot do this for the A1, A2 and RSSI as they are in their own frames. What you will get at the transmitter is the A1, A2 and RSSI values from the link to the box.
To handle A1, A2 and RSSI would require changes to the Tx firmware, as well as an arduino in the box.

Mike.

[jhsa]

See what I mean? My logic is c**p!!!

[ReSt]

Code: Select all

 Radio                           R e l a y                      Plane

Radio PPM      -----> PPM FrSky(RX/TX) -->Booster -------->FrSky(RX/TX)
   A                            |A                                   |
   |                            ||                                   |
   |                            ||-----------------------------------|
   |                            V
APC200     <-------------     APC200
  

Tried to make a picture of what I understand.
Your radio sends the ppm signal to the relay station and ppm is fed into the FrSky TX module (and booster)
Signal goes to the plane with a FrSky two way telemetry receiver
Telemetry data comes back to the relay station receiver part of the FrSky module.

Take the serial output and feed a 'modem' (e.g.APC200) that transmits the data to another APC200.
Connect the serial output of the modem (APC200) to the serial input that normally would be used from the receiver part of the FrSky module.

These 'modems' (APC200) simply transmit the data that you input without adding any framing around. They work like a wireless RS232 cable.

Reinhard

[GTiDon]

The data I am mostly after is the signal strength to the plane from the box.. So thats the rssi?

All the other data I get on the OSD anyway. But extra data can always be added safety and good for plane recovery.

Sent from my LT18i using Tapatalk 2

[Kilrah]

Hmm I understood it differently:
- He has an FrSky module in his radio, that transmits R/C signals to a receiver in the box.
- The receiver's PPM out is connected to a second TX module that transmits to the plane.
- He'd like the info from the 2nd (plane side) system to come back to the radio.

If there's only one RF system in the box with a cable between the radio and the box as ReSt suggests, then just add one more wire for the data. If it's wireless, just do like ReSt suggests with a generic radio modem. I'd try to look into another frequency band though, because 3 RF systems in the same band operating that close isn't a particularly good idea if you're looking for maximum performance.

[GTiDon]

Code: Select all

 Radio                           R e l a y                      Plane

Radio PPM      -----> PPM FrSky(RX/TX) -->Booster -------->FrSky(RX/TX)
   A                            |A                                   |
   |                            ||                                   |
   |                            ||-----------------------------------|
   |                            V
APC200     <-------------     APC200
  

Tried to make a picture of what I understand.
Your radio sends the ppm signal to the relay station and ppm is fed into the FrSky TX module (and booster)
Signal goes to the plane with a FrSky two way telemetry receiver
Telemetry data comes back to the relay station receiver part of the FrSky module.

Take the serial output and feed a 'modem' (e.g.APC200) that transmits the data to another APC200.
Connect the serial output of the modem (APC200) to the serial input that normally would be used from the receiver part of the FrSky module.

These 'modems' (APC200) simply transmit the data that you input without adding any framing around. They work like a wireless RS232 cable.

Reinhard

This looks like it can solve the problem in another way, similer to the bluetooth link mentioned above.

Ideally I dont want to go this route, the idea is to use the radio in hand as is, and also not introduce any extra radio transmitters near to the relay box. On the RCGroups thread 13Km was reached with just a SPW antenna in a stock frsky DIY module and no booster.

[GTiDon]

Look at Post #87 on this thread, this is where the relay box idea comes,, but without telemetry, just so you get the same picture

http://www.rcgroups.com/forums/showthre ... 619&page=7

[GTiDon]

Hmm I understood it differently:
- He has an FrSky module in his radio, that transmits R/C signals to a receiver in the box.
- The receiver's PPM out is connected to a second TX module that transmits to the plane.
- He'd like the info from the 2nd (plane side) system to come back to the radio.

Yes like this, so the radio itself is completely wireless as you would normally use it with no changes at all.

[Kilrah]

OK. So yes, the choices you've got are quite easy:
- Bluetooth or radio modem (they do the same in this case), easiest but a bit of a pain RF-wise.
- Modify the radio FW to remove the "local" link's framing and data before the existing processing.

[GTiDon]

Ok I cant do firmware programming so My last idea is to just use the audio alarms on the transmitter module(relay box) that can be programmed with The FrSky Config program.

How can I amplify the module alarm, is it a speaker or a buzzer?

[GTiDon]

[kaos]

GTiDon:

you may be interested in this:http://www.openrcforums.com/forum/viewt ... &start=540 the last post.

[GTiDon]

GTiDon:

you may be interested in this:http://www.openrcforums.com/forum/viewt ... &start=540 the last post.

Yes thanks. I actually tried that successfully on the weekend!

But I am still stuck with out my telemetry over my relay.


Sent from my LT18i using Tapatalk 2

[kaos]

great, once I get my quad flying right I will ask you some detail how to do it.