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Sep 28, 2017, 08:10 AM
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Build Log

u360gts: 360░ antenna tracker


This tracker seems to be very popular among the Spanish speaking RC pilot's. Yet in this forum there is no information to be found. Once you break the language barrier it's actually a very easy system to setup and use. And therefore I find this system needs to receiver more recognition. Lately I took the time to dig in this project and make one myself. This is a guide with tip's and tricks on how to create and use one yourself based on u360gts. And in general it should be a good guide on how to DIY a proper mechanism for any antenna tracker no mater what brain is driving it. The u360gts supports a variety of different telemetry streams like: MFD, Bare GPS, Mavlink, RVOSD, FrSky X, LTM, PitLab. There is a telemetry autodetect feature! The LTM telemetry is what I use and base this project on. An audiomodem is used to get this telemetry from the air to the ground but different telemetry providing systems could be used, one coming to mind would be the telemetry downlink openLRSng provides.

Here is a visual collection of most of the parts needed to make a 360░ antenna tracker. Some are optional:

There are a few must haves and there are a few optional parts, the different approaches to the tracker are discussed and the list of the parts I used are listed after. There must be a magnetometer on the ground station, therefore a naze32 rev5 full is most easy to setup. But if you have a naze32 rev5 acro and a GPS with a HMC5883L magnetometer, that's also a working combination and the one solution I prefer most. A GPS isn't required though as the first GPS data from a telemetry stream can be used to set the home position. At this moment I can not recommend a naze32 rev6, it does work but requires altering the hardware slightly. Request this if you need this solution.
The necessary parts are:I wanted to build a 360░ tracker that can handle bigger antenna's (is strong and durable) and where wire's don't tangle up therefor the optional parts are:
  • GPS with magnetometer (or without compass when using a Naze32 full) Ublox NEO-M8N Flight Controller GPS
  • FSK Modem for LTM telemetry
  • Buzzer
  • Gears I used: 7050 Metal 48P Spur Gear 80T+22T Motor Gear F SAKURA D3 CS XI S 1/10RC Drift Car
  • Tube ID8 OD10 (inner diameter 8..) 1PCS Roll Wrapped 3K Glossy Carbon Fiber Tube OD10mm*ID8mm
  • Bearings ID10 10pcs Flange Bearing 10mm x 15mm x 4mm F6700ZZ
  • Lazy Susan Turntable 72mm Full Ball Bearing Swivel Plate Metal Lazy Susan Turntable
  • Slip ring 300Rpm Capsule Slip Ring 12 Circuits 12 Wires 12 Connectors 22mm
  • A small bearing when using a big antenna as a second hinge
A direct drive 360░ servo (where all the electronics is in between the two servo's and no gears are used) is possible, but might requires to turn around the drive direction as explained here.

Now we got past the requirements part, it's building time. At this moment the building is up to your own creativity. Maybe a more refined build guide for the hardware will pop up. Keep in mind that the magnetometer has to turn around with the antenna. So the naze32 board and GPS sit above the 360░ pan servo and under the tilt servo, also this tracker is based on a 360░ servo, using a regular fixed travel servo will not work for pan. If you did everything right it might look like:

The 3D printable parts are available on thingiverse, if you want to make a similar looking antenna tracker. More about this is written a little lower.

My first prototype actually looked more like diy style and was also working:


The wiring goes as follows: (It's actually easy once you see this wiring diagram)

The neat trick here is to connect up both the oled and the magnetometer SDA (res. SCL) wires to the SDA (res. SCL) pad. The servo's don't turn on first use so you can safely wire them up. Try to get the 360░ servo's no movement position around 1500ÁS when hacking a fixed travel servo, a little deviation on this number can be trimmed out with the software but it's more easy to have it (almost) right.

Now that the wiring is done, time for the software/settings.
The firmware hex can be found on GitHub here. Upload the firmware using your favorite (clean/beta/base)flight configurator.
The configurator to interact with the antenna tracker is a bit harder at first but once you know the tricks, it's okey to use. You can find the configurator here. Installing this is explained in the GitHub link.
To connect the software with the board it's easier to first setup the telemetry without the software; There is actually a telemetry auto detect feature in the protocol menu. The reason why to set it up like this is to know the baud rate, because the same baud rate has to be used to connect through the configurator with the naze32.
  • Push the 'home' button 1 second to enter the menu.
  • Navigate to 'Telemetry' by pressing the 'home' button 3 times and enter the 'Telemetry' menu by pressing the 'calibrate' button.
  • Change the 'Protocol', enter this menu by pressing 'calibrate' button.
  • Navigate to the wanted protocol by pressing the 'home' button (navigate to LTM) and select 'LTM' by pressing the 'calibrate' button.
  • Navigate to 'Baudrate' by pressing the 'home' button and select 'Bauderate' by pressing the 'calibrate' button.
  • Navigate to '2400' by pressing the 'home' button and select '2400' by pressing the 'calibrate' button. Note down this baud rate
  • Navigate to 'Save' by pressing the 'home' button and select 'Save' by pressing the 'calibrate' button.

Now when you want to connect with the tracker using the configurator, select the '2400' baud rate option to connect. Once connected click the 'CLI Enter' button, if all goes well the OLED screen will mention CLI mode and the parameters are loaded in the configurator where you can change them over. Just like the OSD troubles, it's best to disconnect the telemetry in line while using the usb to setup the tracker.
Now for the tracker to move you will have to double check every setup parameter. The one that definitely need attention are:
  • Pan 0: the pulse value where the 360░ servo does not move.
  • When this value is correct check calibrated.
  • Tilt 0: Antenna pointing horizontal (around 1000 or 2000)
  • Tilt 90: Antenna pointing vertical (around 2000 or 1000)
  • Offset: on the OLED the value "H:" show degrees from north going up clockwise.
  • When this value is correct check 'Calibrated'.
Only when both calibrated options are checked the tracker will ever move.

The 'H:' values on the OLED screen should count upwards while manually rotating the tracker clockwise. If this is not the case this is because the magnetometer is located at the underside of the GPS module 'flipped', enter the following command in the 'CLI Mode' screen from the configurator to get the correct behaviour:
Code:
set align_mag = CW0FLIP
Although at the time of writing the this option isn't in the official release, but a custom hex is available upon request.
Also when 'H:' is zero the tracker/antenna should be pointing north, rotate the magnetometer in steps of 90░ if it is not zero when pointing north.

If on first activation of the pan servo the tracker starts to move out of control switching directions all the time, this is probably because the pan servo's turning direction is inverted as it was intended (just like the drive direction is inverted when you add an extra gear between two gears) Here is explained how to solve this

You successfully read an article on how to make an antenna tracker!
If all is well, and you also build one, it's time to test the new tracker out! Demo video's will follow.
Last edited by jelle737; Sep 09, 2018 at 02:11 PM.
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Sep 28, 2017, 02:16 PM
Chch, NZ
excellent tutorial. I was reading the Spanish blog yesterday (Thank you Google auto translate!) And ended up going round and round in circles on the wiki trying to find this sort of info, i even jumped over to the German blog where it started, by the end of it i didn't know if i was coming or going.
There are a few things i still don't understand, the main one is when they talk about using frsky x mode. How exactly are they getting that telemetry info into the board? Are they pushing it back on Bluetooth from the Taranis?
I saw some photos on the German forum where there seemed to be an frsky rx inside the tracker, is that how they are doing it? But if so, how does that even work?

This looks like a great project, i love the simplicity of it, and if i can get it to work with just an frsky gps in the sky it means i can use it with so many model just by moving the gps around.
I'm definitely interested.

Oh, and thanks for taking the time to work out the important stuff from their forums, you just helped me more in the time it took for me to read this than the 6+ hours i spent reading their forums last night. I was going until my eyes were falling out of my head and i had to get some sleep!
Sep 28, 2017, 04:53 PM
Registered User
Thread OP
Quote:
Originally Posted by Kenniffs
...There are a few things i still don't understand, the main one is when they talk about using frsky x mode. How exactly are they getting that telemetry info into the board? Are they pushing it back on Bluetooth from the Taranis? ...
Thanks for your reply. I can tell the tracker accepts the S.Port telemetry. From back in the days I had a DJT module I know that an external module just had some pins on the back. For getting the internal XJT module S.Port data out of the Taranis I do not have straight answer as I never tried that. But I could find something about this topic on a search. If you are in luck you can just plug in a ground and S.Port telemetry wire in the empty module bay as shown on this page, last paragraph. The page also mentions that telemetry should also be available inside the battery bay on the 4 pin plug (battery balance lead style plug), with just a few settings within the radio.

Keep us updated if you get to the bottom of this and get working telemetry out of the Taranis. Keep in mind the protocol might be inverted and needing some electrical inversion, I feel like a oscilloscope would probably be required to 'see' what's on the pins.

Good luck!
Sep 29, 2017, 04:55 AM
Chch, NZ
well, don't hold your breath that I'm going to be able to work out the bluetooth side of things, component level electronics and programming is something I know absolutely zip about!

Are you able to explain the purpose of the frsky reciever inside the tracker for me? That bit makes no sense to me...
Sep 29, 2017, 05:21 AM
Registered User
Thread OP
Quote:
Originally Posted by Kenniffs
well, don't hold your breath that I'm going to be able to work out the bluetooth side of things, component level electronics and programming is something I know absolutely zip about!

Are you able to explain the purpose of the frsky reciever inside the tracker for me? That bit makes no sense to me...
Point out where I would have mentioned a receiver inside the tracker. There is no receiver inside the tracker. But you need the telemetry data, the GPS part coming from the UAV, to be able to point the tracker. There is no need to use bluetooth in the beginning to test everything out. For a basic test you need buttons, oled and a naze32, if the telemetry data is valid it will be displayed on the oled screen.
Sep 29, 2017, 03:33 PM
Chch, NZ
Sorry if you thought I meant you had mentioned the Rx inside, it is something I have seen in a few of the videos I have watched. Please see the attached screenshot. Maybe it is just for testing?
I have been reading so many of these forum pages trying to understand the in's-and-outs of this thing...maybe I'm over thinking it.

Am I correct in assuming the single line telemetry in is the audio channel from the vtx?

When they talk about it working with Frsky X telemetry are they using a cable connection from the s.port in the module bay of the Taranis back to the tracker or is there a way to feed this down the audio channel as well?

I see plenty of bluetooth units attached to the sides of these things, how does that fit into the scheme of things please?

Sorry for all the questions, I'm just trying to get the last pieces of the puzzle to fit and then I should be good to go!
Sep 30, 2017, 03:13 AM
Registered User
Thread OP
Quote:
Originally Posted by Kenniffs
Sorry if you thought I meant you had mentioned the Rx inside, it is something I have seen in a few of the videos I have watched. Please see the attached screenshot. Maybe it is just for testing?
I have been reading so many of these forum pages trying to understand the in's-and-outs of this thing...maybe I'm over thinking it.

Am I correct in assuming the single line telemetry in is the audio channel from the vtx?

When they talk about it working with Frsky X telemetry are they using a cable connection from the s.port in the module bay of the Taranis back to the tracker or is there a way to feed this down the audio channel as well?

I see plenty of bluetooth units attached to the sides of these things, how does that fit into the scheme of things please?

Sorry for all the questions, I'm just trying to get the last pieces of the puzzle to fit and then I should be good to go!
Yes, in his video it's just for testing purposes. I saw it also and thought you might mean that video. I don't think his tracker got finished to the level he could show a beter video.

In my usecase telemetry is send over audio with two audiomodem chips (one in the air, one on the ground) but any of the available options in the list is allowed. Depends on the kind of aircraft.

For FrSky X, without having looked in this further I think they just use a 2 wire cable (one for ground, one for telemetry). But any example that sends telemetry over bluetooth from the flightcontroller to a ground station will be valid to use on the ground between the taranis and the tracker. I also think that using bluetooth would overcomplicate things in a first build though, it's another pain to setup. I could not find any drone related example that connects two bluetooth modules end to end, here is an arduino example though. It seems like usually a bluetooth connection is used to connect to the phone or computer and use some app or software to read out the data.

I used audiotelemetry but deliberately chose to post that in a separate topic because getting telemetry to the ground is fairly specific to each user .
Oct 14, 2017, 05:10 PM
Registered User
I know this might be a pain, but could you explain what hardware modification is needed for a rev6? i ordered a naze specifically for this project, but unfortunately didn't know it needed to be a rev5 at the time.

Edit: So my buddy had a rev. 5 laying around he parted with. i noticed the buttons and servos are swapped on the pinout above, it took a while to figure out why my buttons weren't working, then i looked at the schematic on the u360gts wiki for the other board and noticed that it was reversed.
i'd still like to make use of the rev6 since i have it and it came with a nice little case to mount it in. too much trouble?
Last edited by jbgrcfreak; Oct 14, 2017 at 08:45 PM.
Oct 15, 2017, 12:45 PM
Registered User
Thread OP
Quote:
Originally Posted by jbgrcfreak
I know this might be a pain, but could you explain what hardware modification is needed for a rev6? i ordered a naze specifically for this project, but unfortunately didn't know it needed to be a rev5 at the time.

Edit: So my buddy had a rev. 5 laying around he parted with. i noticed the buttons and servos are swapped on the pinout above, it took a while to figure out why my buttons weren't working, then i looked at the schematic on the u360gts wiki for the other board and noticed that it was reversed.
i'd still like to make use of the rev6 since i have it and it came with a nice little case to mount it in. too much trouble?
Good eye there! I updated the wiring diagram so it's correct! Thanks for pointing that out, that might have given some headache and a lot of spent time on research.

This is a full naze32 rev6 you have with magnetometer? I had problems with the telemetry data transmitted on the RX pin being eaten up by the usb chip. So you should try out if telemetry is working first, maybe my board was a dud, and as a last resort use the solution provided. I cut the RX trace between this usb chip and the RXpin-STMchip trace (leaving that one intact). The problem with this solution is that it breaks the usb and you need an ftdi solution to configure the board (using the same rx/tx pins). Good luck, let me know how it went. I hope it works out of the box though without modification.
Oct 15, 2017, 09:33 PM
Registered User
Quote:
Originally Posted by jelle737
Good eye there! I updated the wiring diagram so it's correct! Thanks for pointing that out, that might have given some headache and a lot of spent time on research.

This is a full naze32 rev6 you have with magnetometer? I had problems with the telemetry data transmitted on the RX pin being eaten up by the usb chip. So you should try out if telemetry is working first, maybe my board was a dud, and as a last resort use the solution provided. I cut the RX trace between this usb chip and the RXpin-STMchip trace (leaving that one intact). The problem with this solution is that it breaks the usb and you need an ftdi solution to configure the board (using the same rx/tx pins). Good luck, let me know how it went. I hope it works out of the box though without modification.
Ah ok got it! Thanks! I'll give it a shot before cutting the trace and see if it works. If so, i'll report back.
I got the acro version without the mag, so maybe there's a chance it'll work.
Oct 22, 2017, 01:34 PM
Registered User
Thread OP

3D Printed 360░ Antenna Tracker Design


Finally all parts fresh from the 3D printer and assembled in a working tracker!

On a side note here is how to convert a regular travel MG995 Servo to a 360░ servo. This process applies/work for most servo's out there.
Due to the low quality of these servos there is always drift on them, I now use this servo and it made the setup much easier that I cannot recommend to modify one. But this does actually work on better quality servos so here is still how to modify one:
  • Check if the servo is physically limited in travel, if so remove this limitation.
  • Assemble the gears part again but leave the potentiometer out (leave the electronics side open)
  • Apply a servo tester at 1500ÁS (the centre signal, most servo testers show '150'), the servo might starts spinning fast, make sure gears are put together correctly or damage may occur at the gears.
  • Turn the potentiometer until the servo stops turning, (if you turn the potentiometer a little further the servo will start spinning the other direction)
  • At this position where the servo is not spinning apply (hot-)glue at the potentiometer to prevent turning of it in the future.
  • (Just for completeness, if the servo is turning the 'wrong' direction (what's right though ) you can turn around this direction by switching around the wires going to the motor)
  • Now reassemble the servo completely, you successfully converted the limited travel servo to a 360░ continuous travel servo.
On with the main schedule, at around 250g of PLA and 10h production time I present a antenna tracker design:


Here is a view of the inside of the tracker, containing all the suggested parts above (first post) somewhere in the build.


The files to multiply this are available at thingiverse. It's mainly build from plates that press fit together. Good woodwork or a cnc router could be a good alternative to creating the plates to assemble a similar looking antenna tracker. The tracker might also be slimmed out but this size made all the electronics fit easily inside.
Last edited by jelle737; Sep 09, 2018 at 02:19 PM.
Oct 23, 2017, 07:41 PM
Registered User
Clean setup you have there! I tried to print a tracker and did basically the same thing you did, but the 2.4 pepperbox is just too heavy for the tilt to work properly, working on a fix for that at the moment, plus combined with the diversity module from the other thread on the fsk modems, i'll wind up with a pepperbox and helical on the tracker so i may wind up needing something stronger than a servo for the tilt. how difficult would it be to use a stepper motor and driver instead of a servo? or would that involve getting into the source code of the tracker and changing things?
Oct 24, 2017, 03:18 AM
Registered User
Thread OP
Quote:
Originally Posted by jbgrcfreak
Clean setup you have there! I tried to print a tracker and did basically the same thing you did, but the 2.4 pepperbox is just too heavy for the tilt to work properly, working on a fix for that at the moment, plus combined with the diversity module from the other thread on the fsk modems, i'll wind up with a pepperbox and helical on the tracker so i may wind up needing something stronger than a servo for the tilt. how difficult would it be to use a stepper motor and driver instead of a servo? or would that involve getting into the source code of the tracker and changing things?
I think a stepper motor is overkill/too complicated. Since the 360░ rotating mechanism is very sturdy it's good for heavier antenna's. I wanted to use antenna's in the lower frequency I use for FPV but quality has been so good in the limited range the battery allows me to go. The solution I thought at would be to use a 'U' shaped holder where the antenna sits CG balanced in between. Because it's balanced the servo doesn't need to do heavy lifting. A bit like this, but then mount the U shape on the base as above, not on a servo like in the picture (that gives many problems).
Oct 25, 2017, 12:50 AM
Registered User
Quote:
Originally Posted by jelle737
I think a stepper motor is overkill/too complicated. Since the 360░ rotating mechanism is very sturdy it's good for heavier antenna's. I wanted to use antenna's in the lower frequency I use for FPV but quality has been so good in the limited range the battery allows me to go. The solution I thought at would be to use a 'U' shaped holder where the antenna sits CG balanced in between. Because it's balanced the servo doesn't need to do heavy lifting. A bit like this, but then mount the U shape on the base as above, not on a servo like in the picture (that gives many problems).
ah yeah i see. the 360 pan isn't a bit of problem for me, it's just the tilt servo having a hard time i was wondering about using a stepper on. maybe i just need a higher torque servo. looking into printing some gears for it now.
Oct 25, 2017, 02:39 AM
Registered User
Thread OP
Maybe the text is a bit unclear. Use the tilt system like he does. When the big/heavy antenna is nicely balanced, just a simple servo will suffice.


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