DIY Antenna tracker

skyscraper · November 15, 2012, 03:05:33 PM

Decide its time to give this project its own thread.

So whats it all about?

Like everyone else, having been doing fpv for a while, I now have the urge to fly a bit further. However looking round the tracking systems that are available are just a bit too expensive for me.

Anyway I thought.. how hard can it be?

Heres the second video first for the benefit of those that have seen the first already. (The first ones at the bottom)

Note that though I am setting things up for my system , I am keeping in mind other ways of doing things. I hope that by changing some switches you can eventually use e.g a video audio channel for telemetry like the EZ tiny telemetry and others. In other words I hope to make the thing modular and flexible enough to cater for various different setups. One thing I do know. With the STM32F4 micro on board there is a huge amount of processing power availabel to do a lot of stuff. It has to be the awesomest microcontroller out there by a mile !

Anyway ... some progress!

DIY Antenna tracker using STM32f4 Discovery board, Quadrature Encoder PD working

Heres the first video. where I am getting the bits together.

Diy FPV Antenna Tracker using stm32f4 Pololu motor Ardupilot autopilot Frsky telem

I am hoping to put some more detailed info on my website at some stage, but as you may know, programming is much more fun than documentation... at least till you have to revisit it :laugh:

regards
Andy

Coyote · November 15, 2012, 04:29:36 PM

Excellent work, looks very promising :)

skyscraper · November 15, 2012, 06:42:10 PM

Quote from: Coyote on November 15, 2012, 04:29:36 PM
Excellent work, looks very promising :)

Thanks for the encouragement Coyote!

I'm quite keen to emulate your 10 km flight. :P

Matching that might be difficult but I may as well aim high and I''ll certainly need a tracker I think. Just got to try to keep it simple to start with.

regards
Andy

Dizzy · November 17, 2012, 05:18:29 PM

:popcorn: really looking forward to the rest of this :)

dizzy

skyscraper · November 19, 2012, 12:23:26 PM

Quote from: Dizzy on November 17, 2012, 05:18:29 PM
:popcorn: really looking forward to the rest of this :)

dizzy

Thanks for the interest.

Actually I think it might not be very difficult to get it to work with the EZtracker ( and still have continuous rotation), if I set it up to read servo pulses!

Am looking into it as an option!

regards
Andy

skyscraper · November 19, 2012, 12:32:10 PM

Quote from: aitch on November 19, 2012, 12:27:10 PM
dont think the eztracker supports continuous rotation ... does it ?

Aitch :laugh:

Dunno yet... Trying to get my hands on one, without forking out, (seeeing as that the point of the project!) Theoretically it should work fine!

Would be nice if it does though!

regards
Andy

Coyote · November 19, 2012, 01:08:42 PM

No it doesn`t support continuous rotation, 360 degrees only

skyscraper · November 19, 2012, 02:42:15 PM

Quote from: Coyote on November 19, 2012, 01:08:42 PM
No it doesn`t support continuous rotation, 360 degrees only

Well technically that is continuous, since 0 degrees equals 360 degrees. Anyway I assume that is is just using the servo pulse to tell the servo where to put itself :
http://www.immersionrc.com/manuals/EzAntennaTrackerLiteUserManual.pdf

Because most hobby servos cant go all the way round then its academic fro them but since my servo can then its merely a question of how you get from 359 to 0 . Most servos can only go one way, but mine can go either way :D

It is possible to set it up for servos wth more that 360 degrees rotation, but my approach would be to set it up for 0 - 359 degrees.
The only issue is if it tries to be smart and when it wants to move from (say) 359 degrees back to 0, to do it gradually in steps.

However the "servo speed" setting (2:13) may be what adjusts that. If it doesnt try to be smart then the servo algorithm that reads the position commands (the pulses) can decide which is the shortest path to go from 359 back to 0 and go that direction.

Anyway even if it doesnt (but my hunch is it will work ok) I might consider writing to immersionrc ,showing my video and suggest that it would be easily possible to do so in a later version (that is go from a long pulse to a short pulse in one step), since they dont actually sell the mechanical parts anyway, that would increase the versality

regards
And

wgt40w · November 19, 2012, 06:54:26 PM

Most commonly used for the Pan on an antenna tracker is a "Sail Winch" servo - designed for use on rc sailing boats - they normally are capbable of approx. 4 complete 360 degree rotations.

It is the EZ Tracker setup that controls the 360 degrees rotation of the servo - can be set to anything up to 360 degrees.

skyscraper · November 20, 2012, 08:08:23 AM

Quote from: wgt40w on November 19, 2012, 06:54:26 PM
Most commonly used for the Pan on an antenna tracker is a "Sail Winch" servo - designed for use on rc sailing boats - they normally are capbable of approx. 4 complete 360 degree rotations.

It is the EZ Tracker setup that controls the 360 degrees rotation of the servo - can be set to anything up to 360 degrees.

If you look at the manual, it is possible to set up for maore than 360 degree rotation..

manual 2.15 "ServoCity pan/tilt mount , SPG785 Pan (2:1, 630 degree option), DDT500H Tilt"

Anyway I am pretty confident I could get continuous rotation from the EZtracker using my servo using an encoder rather than a pot for position info.

Its academic unless I can get one though without paying for it, however I am certainly looking into using the video audio channel to send data as the EZtracker does..

regards
Andy

Teamftp · November 20, 2012, 01:23:37 PM

After buying an Eagle Tree mount and not been overly impressed with it I have to decided to have a go at making my own.

The joys of working in a school and having a laser cutter!!

skyscraper · November 20, 2012, 01:47:11 PM

Wow ... Looks nice!

Especially since my weakpoint is the mechanical hardware. Only got a hacksaw!

Pressing on with the software though.

regards
Andy

Teamftp · November 20, 2012, 03:26:02 PM

Yours look blmin awesome and super stable!!

Problem was with my Eagle Tree mount was the pan axis had load of play in it. I have bought a new pan servo drive and then made this to suit it all.

Just hope it works now. Will put it all together tonight and see what happens.

Teamftp · November 20, 2012, 03:30:00 PM

I have used this for the pan aspect of my tracker.

It is awesome and has LOADS of power!!!

It is also super smotth which is nice.

http://www.fast-lad.co.uk/store/products_50kg_ultra_torque_servo_rotation_10226031-p-18911.html

wgt40w · November 20, 2012, 04:06:17 PM

Quote from: Teamftp on November 20, 2012, 03:30:00 PM
I have used this for the pan aspect of my tracker.

It is awesome and has LOADS of power!!!

It is also super smotth which is nice.

http://www.fast-lad.co.uk/store/products_50kg_ultra_torque_servo_rotation_10226031-p-18911.html

Blimey - what antenna would you put on top of one of these ?? The whole Post Office tower maybe ??