Thread Tools
Apr 11, 2016, 12:44 PM
Stuart
srnet's Avatar
Thread OP
Discussion

Easy Build - LoRa Long Range Lost Model Tracker


Eventually I have come up with a LoRa tracker design that is small, low cost but very easy to build, it can be built without you needing to solder SMT components.

The same board layout is used for the transmitter and receiver. The tracker runs off a small Lithium backup battery which can be kept charged from a connection to the radio control receiver.

The receiver can use a Bluetooth connection to an Android mapping application for a direct display of where the tracker is. The mapping application does NOT need an active Internet connection to work. You can also use a small LCD\TFT display and the receiver will show you the location of the tracker. Fit a GPS to the receiver and it is able to calculate and show the distance and direction to the tracker.

For now most of the documentation and build instructions are here;

https://goo.gl/IeEiC1

There is a general introduction to tracking with LoRa in the document;

“Long Distance Tracking and Monitoring with LoRa - Introduction - March 2016”

At some point in the future I hope to put together a mini kit of all the small bits, leaving the constructor just needing to buy a DRF1278F or RFM98 LoRa module, Pro Mini and GPS.

To get a pair of tracker boards visit my website;

http://www.loratracker.uk

I wont be selling completed trackers, nor will the PCB designs be published.

.
Last edited by srnet; Sep 18, 2016 at 12:45 AM. Reason: Added note about DRF1278F
Sign up now
to remove ads between posts
Apr 11, 2016, 12:45 PM
Stuart
srnet's Avatar
Thread OP
Reserved for later
Apr 11, 2016, 05:19 PM
Registered User
When do you think that the mini-kits will be available?
Apr 12, 2016, 01:13 AM
Stuart
srnet's Avatar
Thread OP
Quote:
Originally Posted by Bearded Flyer
When do you think that the mini-kits will be available?
Probably 2 weeks or so, I have most of the stuff here, its just finding the time to organise kitting them up.
Apr 14, 2016, 12:19 AM
Stuart
srnet's Avatar
Thread OP
I am looking at sourcing the LoRa device as part of a kit to.

Hope, who supply the RFM98, does not look promising at the moment.

Dorji does look more promising, and their device (DRF1278F) is more widely available in some places as well.

There is an alternative PCB, same size and layout that will take the Dorji device, performance is the same as the RFM98.
Apr 22, 2016, 02:35 PM
Stuart
srnet's Avatar
Thread OP
There was a high altitude balloon flight in the UK yesterday using LoRa, so I setup my receiver to listen, see picture.

The receive antenna was a Diamond X50N on a 4M mast in the middle of the city where I live.

Distance to the transmitter was 270km, altitude for the received packet below was 12836M

PacketRX SNR,-8dB,RSSI,-99dB,LEN,60,Type,$
$$X0,1134,16:56:02,52.15117,0.46023,12836,13,3,3.1 8,00*B929

Link margin at that altitude was circa 10dB, so the link ought to be good for circa 800km.

Transmit power of the remote tracker was 10mW.
Apr 22, 2016, 02:37 PM
Registered User
That is very impressive!
Apr 23, 2016, 08:10 AM
Stuart
srnet's Avatar
Thread OP
LoRa is impressive in the right circumstances, and it really excels at low data rate comms.

The receiver code I used for listening to the balloon is the same as posted on the dropbox, with the LoRa modem settings adjusted for the particular bandwidth the transmitter was using.

In the UK we cannot use APRS for tracking balloons, so up till now most of the tracking has been done by transmitting FSK RTTY in the ISM bands. LoRa performs about the same as FSK RTTY but has the advantage of being two way and if your transmitter is close enough you can use much higher data rates than were ever possible with FSK RTTY.

I do have some code for a high altitude balloon tracker, it will be published sometime soon.
Last edited by srnet; Apr 23, 2016 at 01:53 PM. Reason: typo
Apr 26, 2016, 06:21 PM
Registered User
Introducing LoRa Tracker GoogleMaps Client and Server Scripts:

This program extends LoRa Tracker Project started by Stuart Robinson a.k.a. "SRNET"

Special Thank You to Stuart Robinson for the great efforts and time invested to the project, especially in research and hardware development.

I do frequent updates to both Client/Server/Hardware + field tests, expect interrupts. If there are no updates to the data, it means I am making some changes to software/hardware.

Both Client and Server written in JavaScript, with LoRa module (srnet version) connected to laptop by Serial to USB bridge. Packets set to be send every 15 seconds. You can notice some GPS fluke because of the GPS location - most of the time tracker sitting on my basement window, next to my table.

Enjoy!

Vadim Afonkin
KB1RLI
Last edited by KB1RLI; Apr 26, 2016 at 10:39 PM.
Apr 27, 2016, 05:41 AM
Registered User
srnet : Can't sent you PM, your inbox is full, posting it here for now:

Regarding "lost mode" coordinates - Never mind, I forgot sentence is not converted NMEA data. Everything is fine.
Apr 27, 2016, 01:01 PM
Stuart
srnet's Avatar
Thread OP
Quote:
Originally Posted by KB1RLI
I would not use and display the raw terminal output from the receiver in that type of application, it was not intended for that purpose.

Due the limitations of the conversions from strings to floats and back to strings the lat\lon strings in the received packet, the internal lat\lon as float and the lat\lon in the NMEA output have slightly different values, so people viewing the Google map page with no knowledge of the background software could easily assume its a bug.

The differences in the calculation and conversions are of little consequence, position errors are typically less than 1M, so not a lot to worry about, especially given that GPSs typically used will normally have position errors several times this.
Apr 27, 2016, 02:04 PM
Registered User
Quote:
Originally Posted by srnet
I would not use and display the raw terminal output from the receiver in that type of application, it was not intended for that purpose.

Due the limitations of the conversions from strings to floats and back to strings the lat\lon strings in the received packet, the internal lat\lon as float and the lat\lon in the NMEA output have slightly different values, so people viewing the Google map page with no knowledge of the background software could easily assume its a bug.

The differences in the calculation and conversions are of little consequence, position errors are typically less than 1M, so not a lot to worry about, especially given that GPSs typically used will normally have position errors several times this.
I included technical data for those interested to see raw data. This is valuable especially for field testing and debugging.

I access this page while I have tracker with me and access it on mobile phone to check data received.

Lat/Lon at the top calculated in JavaScript from data provided by tracker.

I can leave to display only RX link quality data.
Last edited by KB1RLI; Apr 27, 2016 at 02:38 PM.
May 02, 2016, 06:32 AM
Registered User
Probably a stupid question but, can a DRF1278F be used instead of the RFM98? Having a difficult time finding a RFM98.
May 02, 2016, 11:41 PM
Stuart
srnet's Avatar
Thread OP
Quote:
Originally Posted by radiofreq
Probably a stupid question but, can a DRF1278F be used instead of the RFM98? Having a difficult time finding a RFM98.
Well ......the DRF1278F uses a different pinout, so you can guess the answer.

I am working on a PCB for the DRF1278F but its not ready yet.

HopeRF have distributors in most countries.
May 07, 2016, 05:58 AM
Registered User
Quote:
Originally Posted by srnet
Well ......the DRF1278F uses a different pinout, so you can guess the answer.

I am working on a PCB for the DRF1278F but its not ready yet.

HopeRF have distributors in most countries.
Thank you. I'll keep looking.


Quick Reply
Message:

Thread Tools