Basic GPS tracker

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vance2loud
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Basic GPS tracker

Postby vance2loud » Wed Oct 21, 2015 10:41 pm

I have had reasonable success so far with a basic GPS tracker consisting of a 3dr telemetry radio set and a GPS module.
I have been connecting it direct to a laptop and have been able to record flights to 6000 feet reliably (apart from not many gps points on the way up possibly due to the velocity and 1Hz gps refresh)
I would like to now improve on the system by adding a receiver that would show coordinates, Altitude and ideally a direction to the transmitter.
What are peoples thoughts on what features would be best to implement?
The current system costs around $50-60 to build (plus the laptop) and additional transmitters are around $40 each including rechargeable batteries.
Over the next few weeks I will try to post a full how-to on the system that I am using for feedback and so others can easily create their own.
I also plan to experiment with using higher power radio links for those who wish to push their rockets a bit higher and/or who's rockets tend to land further away.
I did consider adding extra functions to the transmitter such as a barometric sensor but I think at the moment the transmitter works and I might be best to leave well enough alone to start with.
The receiver box that I am considering will be able to work at the same time as the laptop so if it fails I will still have at least one source of data to work from.
the only addition that I have considered adding to the transmitter is a data logger to ensure that even if the radio link is temporarily lost I would be able to review all the data once the model was located.
Some of the ideas that I have thought of incorporating into the receiver come from these:
http://marcusjenkins.com/hardware/arduino-based-geocache-finder-toy/
for the pointer idea
http://www.seancarney.ca/projects/arduino-gps-receiver/arduino-gps-system#.VieHbXWlxBc
for the display.
I don't have much experience with the arduino side of the project so I thought I would get peoples ideas first to see what everyone thought would be of most use to us.
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Thu Oct 22, 2015 2:52 am

For those that are still reading here is the parts list: (search for terms between " " to find suitable parts)
1 x pair "915 telemetry" radios ($15 - $200 depending on brand and output power)
1 x "u-blox gps module" (look for unit too suit apm and preferably with 3-5v power requirement)(for a faster lock and better signal look for units with an "active" antenna)($20 - $60 depending on module)
1 x 600mAh hobbyking battery with JST connector https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=35544 ($4 +/- , I usually buy multiples when I am ordering other parts from them)
1 x "JST lead" personally I use a 5 to 1 lead and cut it into 5 separate power leads ($2 - $10)

Also needed is:
Laptop
Soldering Iron and solder
Side cutters or similar tool to cut and strip wire
Lithium battery charger (either dedicated unit or lithium powerbank modified for the task - more details later)
Side note: Charging Lithium batteries has risks, please research charging options and safety considerations before charging. I accept no risk ..... you know the drill.
also soldering and most things in rocketry have inherent risk involved, if you are not comfortable with the instructions that I give please ask questions and understand that I take no responsibility for your actions.
Attachments
$_12.JPG
5 to 1 JST lead
$_12.JPG (21.65 KiB) Viewed 4115 times
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battery with jst connector
9210000002(1).jpg (136.6 KiB) Viewed 4115 times
$_57.JPG
Gps module
$_57 (2).JPG
telemetry radio pair
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

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lorstin
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Re: Basic GPS tracker

Postby lorstin » Thu Oct 22, 2015 6:42 am

Check out this crowd Vance, I'm not sure if they've got quite what you're looking for. I've always found them reasonably priced, free postage and usually quicker than alot of overseas sellers.

http://www.banggood.com/buy/tx-rx-module.html

I also recently saw a small rx/tx module for about $1 but can't for the life of me remember where it was. If it comes back to me I'll let you know.
caveat emptor :?

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Thu Oct 22, 2015 11:10 am

Thanks for the link Lorstin, I prefer the HopeRF radio modules due to the frequency hopping and the allocatable NetID which allows for multiple radios to used at the same time without interfering with each other.
Banggood does list them for sale but they are slightly more expensive, Ebay regularly lists them cheap or if you want top quality units you can't go past RFDesign http://store.rfdesign.com.au/ for Australian designed long range units.
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

Lister
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Re: Basic GPS tracker

Postby Lister » Thu Oct 22, 2015 11:16 am

Thanks vance. this is exactly what I need.. gonna be fun testing these next year.

for lower power stuff I reckon this is hard to beat

http://www.jaycar.com.au/Alarm-%26-Asse ... l/p/XC0362

strud
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Re: Basic GPS tracker

Postby strud » Thu Oct 22, 2015 3:34 pm

You can get the Hope RF modules from Aliexpress.

Something to consider though is that these type of modules typically do not have a UART interface but use SPI.

The documentation is a little less than perfect, but if you have a look at my thread on the generic telemetry stuff, you can see that they use a number of radio modem chips from Si Labs.

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Thu Oct 22, 2015 4:28 pm

Thanks for that Strud,
Your threads are a big part of what made me want to build these trackers to start with.
I didn't realise that the HopeRF modules are natively SPI, I have purchased some but haven't tried connecting them yet.
My aim for this project is to keep it as simple as possible to allow anyone with basic soldering skills (ie me :roll: ) to be able to make something work.
I notice that you use the 70cm band on a few of your projects, How big a difference is there in range? So far I am trying to keep this in the unlicensed bands so anyone can use it.
I would love to be able to construct something like your project, but I still have a lot to learn about how this sort of system works.
Have you considered selling your system either complete or in kit form?

This is a good reason to use the 3dr radios and/or clones thereof, they already have the extra parts required to allow them to interface directly with the GPS module and the power regulators to allow them to run direct from a 1s lithium battery (not quite the ideal voltage but within the safe range and it works). If using the larger RFDesigns RF900 radios a bit of extra work and components is required to supply the necessary power.
The RF900u can work directly with this project and will increase the range to 10km (Their spec, not tested) but increases the cost substantially.

Of note also is that the RFdesigns radios are compatible with the 3dr radios and their software so it is possible to use different radios at each end of the link as long as they are configured similarly.
I still need to check if using a larger receiver with diversity would give any worthwhile improvements or if the transmitting radio and it's antenna make the biggest difference.
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Thu Oct 22, 2015 5:21 pm

For this project there is only the following bits of software required;
3DR radio configuration tool http://ardupilot.com/wp-content/plugins/download-monitor/download.php?id=89
U-blox u-center https://www.u-blox.com/sites/default/files/u-centersetup_v8.18.zip
you may also need some drivers which hopefully auto install on your system (they did on mine)
and google earth https://www.google.com/earth/
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

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Happy Heyoka
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Re: Basic GPS tracker

Postby Happy Heyoka » Thu Oct 22, 2015 6:36 pm

Vance,

I have written an Android app that shows a map with both the Android device GPS fix and the fix from the rocket GPS on the other end of the radio link; I have a second "compass rose" view that shows actual (using magnetometer) heading and distance to the rocket - or at least the surviving bit with the radio :wink:
It's rough and it's only tested on the couple of Android devices that I have but is way more portable than a laptop and easier to view in sunlight (at least with the OLED display on my phone).

I'm using Google maps so you need to cache the map before you go to the field (or have good cellular reception where you fly)... the compass rose thing of course works just fine without internet etc.

My radio setup is using 433MHz HopeRF modules that have Arduinos integrated (or vice versa) - just like yours - so the who show is the size of a matchbox... it's highly likely you're using exactly the same libraries I am on the Arduino.
I think I got a better deal on the radio/arduino things - I got about four of them for $50 (no antennas though - I made mine)
Ha ha ha ha ha! You can't fool me! There ain't no Sanity Clause!
Chico Marx - A Night at the Opera (1935)

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Thu Oct 22, 2015 7:16 pm

I would be interested to see your program happy heyoka.
The device that I am describing here doesn't have any arduino built in as far as I know. It is simply a radio link connecting the gps to the laptop. If your program can handle a direct usb connection it would be great. I tried using one program which required a bluetooth bridge and I could not get it working with any of my android devices. It worked fine to my laptop via bluetooth but not my android devices so the hardware seemed ok.
one thing to watch for is that the 433mhz radios are legally only meant to transmit a maximum of 25mW EIRP in Australia whereas a frequency hopping 915mhz radio is allowed 1W for telemetry use. 40 times the radiated power can make a big difference in range. Ignore all that if you have your Ham licence and/or know of a different rule.
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Thu Oct 22, 2015 10:43 pm

a selection of 915mhz radio modules awaiting testing.
From Left to right. $15 ebay 3dr clone, Hextronic 3dr clone (approx $35), RFdesigns RFD900u ($75 when available), RFdesigns RFD900 (superseded, new version RFD900+ approx $90)
The first three are 100mW modules and the larger RFD900 is rated at 1W. Both RFDesign radios have diversity built in hence the two antenna connections.
All of these radios have frequency hopping and basic error correction and all are able to be interchanged with each other and don't require matching pairs of radios.
Hopefully I will get all of these out soon and find somewhere to give them a ground based line of site range test.(Could be difficult with the Larger RFD900 as it has an advertised range of 40-50km)
I will be using the RFD900 and a genuine 3dr ground module as the receive modules for the tests as I feel that should give a reasonable indication of what works well together and what range we can expect.
I will test them with the supplied antenna's and then will try to test them with the RFDesigns supplied antenna's to remove that variable from testing.
Unfortunately I don't have an xbee radio to test as well but I think these will cover most configurations that we wish to use.
I do also have some cheaper clone radios with "soft" antenna's on their way that I plan to use for the rest of the instructions on how to set up a basic GPS tracker.
Attachments
20151022_231015a.jpg
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

Lister
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Re: Basic GPS tracker

Postby Lister » Wed Jun 01, 2016 7:00 pm

Gday Vance. My transmitter/receiver arrived yesterday. I pulled it out of the plastic case and can see the solder points. Few questions. What points on the gps module do I solder the wires to and where do I attach the wires onto the transmitter?

Also as I mentioned at the last launch I have a couple of HC-06 Bluetooth transmitters that I want to attach to the receiver to be able to run it through my phone. Im guessing I can just de-solder the usb connection and replace it with the HC-06? Do all usb connections have the terminals in the same place.. for example from left is - , +, something, something?
Attachments
2016-06-01 18.52.18.jpg
2016-06-01 18.52.18.jpg (130.2 KiB) Viewed 3874 times
2016-06-01 18.52.45.jpg
2016-06-01 18.52.45.jpg (113.68 KiB) Viewed 3874 times

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Wed Jun 01, 2016 8:04 pm

On the G.Top PA6H GPS (I think that's what you have).
Pin 1 = vcc (power+)
Pin 3 = gnd (power-)
Pin 9 = Tx
Pin 10 =Rx

The Rx and Tx may be mislabelled on the radio, they were on the last one I soldered. Once you have the gps and battery lead soldered on plug a 1s lipo in and and plug the usb into your computer. Then download and install ucenter from ublox. Open the program, select your computer port and place your gps transmitter in a windows or outside. After a minute or so you should start to see satellites appearing on the screen. If not disconnect your battery and swap the Tx/Rx pins in the radio plug (most of those plugs have little lock tabs that you can lift with a pin or sharp knife, just be careful not to break them).
Once they are swapped plug the battery back in and try again.

The Bluetooth will need to be connected between the radio module and the usb chipset, or get another air module and wire them together.

I'd get the gps working first before working on the Bluetooth.
Sorry it's a blurry picture, keep the wires as short as you can and secure everything with hot glue AFTER you test it.
Attachments
_20160601_201032.JPG
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison

Lister
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Re: Basic GPS tracker

Postby Lister » Wed Jun 01, 2016 8:41 pm

Thanks Vance. You can't get much easier than that.

do you mean to wire the Bluetooth transmitter to the usb chipset.. so leave the usb in place and just heat the solder to add wires for the HC-06?

Does anyone have an old laptop laying around they would like to sell to me so I can use this through GPS on site? :mrgreen:

vance2loud
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Re: Basic GPS tracker

Postby vance2loud » Wed Jun 01, 2016 8:51 pm

The usb has a ftdi232 (or something like that) chip that connects the usb to the hoperf module. You need to connect the Bluetooth to the radio module before that chip changes the signal to suit usb. You can either find the Tx and Rx points or get another air module to make the Bluetooth bridge. I haven't had much luck with Bluetooth modules so hopefully someone else can chime in.
That's why I was asking about HappyHeyoka's software at the last launch. He said that it should be able to work with an OTG cable directly into an android phone.
TRA #15165 AMRS #50
I do it because i can, I can because I want to, I want to because you said I couldn't. - Unknown
I have not failed. I've just found 10,000 ways that won't work.
- Thomas Alva Edison


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