GPS module locator system by local radio type signal

Projects General Guidance
1

I have a need for a system of GPS locators to transmit their location back to me over a simple local system like a radio transmitter.

The locator unit needs to be very lightweight and low-cost.

The purpose is to make tracking collars for my animals such as goats, sheep, on a 30 acre block including trees, small hills etc, with no access to mobile network.

The areas are well within for instance walkie-talkie signal range, and my understanding is that in it's simplest form, all I have to transmit back to my receiver is a set of co-ordinates?
Isn't this sort of how it works with the GPS unit on a quadcopter?

My problem is that I have no mobile service and the units I see made send their location via a sim card module and therefore need service and I would have to keep them all payed up, which simply isn't an option for at least a half dozen units.

Obviously all sorts of user-friendly functions like integrating with a map image or viewing the last hour on a 10-minute snapshot run would be nice but if I can establish the basics then I can go from there.

What would be the best way to accomplish this?

2

If all animals send their coordinates at the same time, or at arbitrary times, each sender must send on a different channel, and you need a distinct receiver for each channel. Not a good idea, IMO.

One idea makes your base station send the ID of a mobile station, whereupon this station sends its data. Then the next ID is sent, and so on.

3

DIY RFM69 GPS dog tracker. Uses OpenHAB for mapping. RFM95/95 LoRa have longer range than RFM69 radios. Lots of information on RFM radios for use with Arduino compatible boards at lowpowerlab.com and adafruit.com.

https://www.hackster.io/erictsai/uber-home-automation-fd5a0f/logs/4

4

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

One of you biggest obsticals will be power usage, the commercial units will have over come this to a certain extent.

Starting from scratch to build a similar system, is a big task as you would have to basically design and construct custom PCBs and coding.

Can you please tell us your electronics, programming, Arduino, hardware experience?

Thanks.. Tom... :slight_smile:

5

Well if you want to do your own packaging then you can build simple LoRa trackers like this;

Specifically designed to be very low power consumption, runs the Arduino in sleep mode and GPS in hot fix. If you send a location fix every 10 mins or so, expect more than a years life out of some Alkaline AAs.

The electronics is simple enough, but the real issue is the packaging of such a device. Needs to be robust, waterproof and maintainable.

6

DrDiettrich:
One idea makes your base station send the ID of a mobile station, whereupon this station sends its data.

In fact, that would be OK, at least for mark 1 design it would be perfectly satisfactory even if I manually send a request to each unit ... most times one would be sufficient to locate a whole group, only when one member is missing I could then immediately locate that member ... even this simple use would have saved a life last week, thus my urgent renewal of this project from "theory" stage.

TomGeorge:
Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

One of you biggest obsticals will be power usage, the commercial units will have over come this to a certain extent.

Starting from scratch to build a similar system, is a big task as you would have to basically design and construct custom PCBs and coding.

Can you please tell us your electronics, programming, Arduino, hardware experience?

Thanks.. Tom... :slight_smile:

Power consumption was one of my next research goals ... I'm thinking of using an 18650 lithium battery as a standard power supply.

I'm having a lot of trouble finding a commercial, or even DIY, system that does what I need ... as most either work on GPS and mobile service (which is unavailable at my address) or else simply locate a signal's strongest point.
Frankly the later system was abandoned after chasing my tail all over the farm with signals bouncing in all directions, and losing 2 out of 4 collars because they fell off AND stopped working.
I tried to set up a triangulation system but learned early that the terrain was not at all suitable.

Experience for hardware good, electronics fair, programming and arduino advanced learner.

No problem tackling big tasks ... the only question is, how many 15 hour crash learning sessions it will take me to pull off the coding Lol.

srnet:
Well if you want to do your own packaging then you can build simple LoRa trackers like this;

Specifically designed to be very low power consumption, runs the Arduino in sleep mode and GPS in hot fix. If you send a location fix every 10 mins or so, expect more than a years life out of some Alkaline AAs.

The electronics is simple enough, but the real issue is the packaging of such a device. Needs to be robust, waterproof and maintainable.

This seems very much the basic system I need to set up.
Packaging is going to be kind of interesting regardless of what electronics is used, but I'm confident I can achieve that even if I have to set all non-essential access points in resin once everything is up and running.

A location fix every 10 minutes or so would be perfectly fine, in fact I had considered making a GPS logger to SD card and simply asking it to send me the data (say, just the last 10 results) on request. That would cut the transmissions down to once or twice a day.

7

ebarnes88:
This seems very much the basic system I need to set up.

For your current requirement, @ 30 acres, the receiver is never going to be far from the transmitters and there is no compelling reason to use the (very) long range LoRa devices.

However, when taken into account the time and effort for producing a complete working device, a saving of maybe $2 on the radio device seems rather pointless.

If an animal goes AWOL, then a LoRa based tracker gives the significant advantage of allowing very large areas to be searched very quickly, read this for an idea of the possibilities;

How to Search 500 Square Kilometres in 10 minutes

8

srnet:
For your current requirement, @ 30 acres, the receiver is never going to be far from the transmitters and there is no compelling reason to use the (very) long range LoRa devices.

However, when taken into account the time and effort for producing a complete working device, a saving of maybe $2 on the radio device seems rather pointless.

If an animal goes AWOL, then a LoRa based tracker gives the significant advantage of allowing very large areas to be searched very quickly, read this for an idea of the possibilities;

How to Search 500 Square Kilometres in 10 minutes

Agreed on the savings not necessarily being worthwhile at that point ... and it allows for better reliability on penetration of the many trees etc and terrain involved. If they go AWOL they can tend to get a long way up the river rapidly (say another 1000 metres in the first few hours depending on the weather) so additional range would not go amiss.

Another major project up next is building a drone so a similar unit would also be useful for that.

I shall proceed sourcing electronics and assembling this tracker project and let you know how it goes.

9

ebarnes88:
Agreed on the savings not necessarily being worthwhile at that point ... and it allows for better reliability on penetration of the many trees etc and terrain involved. If they go AWOL they can tend to get a long way up the river rapidly (say another 1000 metres in the first few hours depending on the weather) so additional range would not go amiss.

For some tests of how good LoRa can be at penetrating forests read this;

Lost in a (wet or dry) Forest