Home › Arduino APRS Tracker

Arduino APRS Tracker

An APRS tracker is easy to build these days.

I had decided to build one for portable use (plan is to be used on hiking, but also in my car) powered from Lithium Ion battery and with all components running on 3.3V. Transmit of APRS messages is done through a UV-5R.

The tracker is powered from my favorite Panasonic NCR18650 3400mAH through a MCP1700-3302E LDO regulator, and has plenty of juice for daily use.

GPS is a Adafruit Ultimate GPS Breakout – 66 channel w/10 Hz updates (https://www.adafruit.com/product/746) not that i need 10 Hz, 1 Hz update is more than enough but i had in stock from a different project, so why not ? (i love it)

Arduino is a Pro Mini 3.3V 8 MHz (actually a clone of Deek-Robot Pro Mini)

Up and running on breadboard

Update

Bought a Kenwood cable to avoid the mess with the 2.5 and 3.5 mm audio connectors

BIG FAT WARNING : There is no load disconnect for the battery while charging. DO NOT CHARGE AND USE IT. The charging of the battery will never finish, resulting on explosion, fire etc. YOU HAVE BEEN WARNED

https://www.aliexpress.com/item/DIY-2-pin-4-Wire-Speaker-Mic-Cable-Spring-Line-for-Baofeng-UV5R-Kenwood-TK370-Linton/32734963747.html
Added also a TP4056 Lithium Cell Charger Module with Battery Protection to charge it through USB.

https://www.aliexpress.com/store/product/5x-TP4056-Lithium-Charger-Module-with-Battery-Protection-Micro-USB-5V-1A-TE420/1895489_32646760134.html

I have started working with the schematic of MicroModem (http://unsigned.io) but i have modified LibAPRS to make it work.

As long as GPS has a FIX it submits my location every two minutes and i have a button for a single shot APRS update. SmartBeaconing support is included (check the relevant branch on github)

The idea is to create a complete unit with a DRA818V with USB charging.
DRA818V is still on my desk… i have “trouble” designing a good low pass filter for VHF.

Schematic (breadboard version)

Remember power supply needs to be 3.3V

Arduino APRS tracker schematic (for the breadboard version)

Documentation has not been finalized yet and i use multiple libraries making it a bit difficult to handle everything

I have uploaded my working version to github
https://github.com/billygr/arduino-aprs-tracker

Remember to change the APRS_CALLSIGN to your call sign

You will need these libraries
libAPRS (modified) https://github.com/billygr/LibAPRS
TinyGPS http://arduiniana.org/libraries/tinygps/
SimpleTimer is included in the project (delete your version from Arduino/Libraries)

PCB

Oh yes !!! We do have also PCB ready credits to aronaut. Thank you !!!

https://github.com/billygr/arduino-aprs-tracker/tree/master/APRS-Tracker_KiCad

Bill of Materials (breadboard version)

R1 1K
R2 2K2
R3 3K9
R4 8K2
R5 270
R6 10K trimmer
R7 1K
R8 10K
C1 100nF
C2 4.7uF/16V
1x GPS Module
1 x push button
1 x Arduino Pro Mini 3V3 8MHz
Q1 2N2700/BS170

For using without an external power supply
1 x Panasonic NCR18650 3400mAH (or your favorite 18650)
1 x 18650 socket
1 x MCP1700-3302E

Bill of Materials (PCB version)

Includes the 18650 socket+TP4056

https://github.com/billygr/arduino-aprs-tracker/tree/master/APRS-Tracker_KiCad

290 Comments on “Arduino APRS Tracker”

  1. Billy my ideas for perfect baloon tracker in your project
    Altitiude above sea level in APRS report
    2x BME280 sensors in APRS telemetry
    Battery voltage in APRS telemetry

    Reply

  4. I try to upload your heavy job to my board but after verification I receive info : “APRS_setSpeed was not declared in this scope”

    Reply

  5. Tell me please, I put your firmware on the tracker based on Arduino Pro Mini 3.3V 8 MHz and gps module NEO-6M-0-001, the tracker aprs transmits, but for some reason the SmartBeaconing system does not work, something in your firmware needs to be enabled or the GPS module not suitable for work. I put the firmware from here: https://github.com/billygr/arduino-aprs-tracker/blob/master/arduino-aprs-tracker/arduino-aprs-tracker.ino
    I can not figure out how to make it work, the coordinates are transmitted by the tracker when updating after 2 minutes. And when turning, turning and changing speed, nothing. I will be grateful for your help.

    Reply

    • Hi,

      I just checked both pictures, there is no conversion in my code , we get the output directly from TinyGPS.
      Could you please be so kind and do a test the test_with_gps_device.ino from the TinyGPS library ?

      73, SV1QFV

      Reply

  12. Billy
    According Your next aprs nice project … ( not possible to comment there )
    Not better use diferent low pass filter ? http://599.cz/view.php?cisloclanku=2018082201 – please see – easy to make and prepare. LFCN-160+ very difficult to get ( expensive item + expensive delivery ) – If You have cheap source for it please let know
    Please consider
    Regards

    Reply

  14. Hola te consulto cada cuantos minutos emite la posicion o hoy que oprimir el boton para que lo haga, saludos LU7FDV

    Reply

  16. Hi, Billy

    From your Arduino code, we didn’t see any code relevant to pin D4 to D7. Can you pls explain how your code work?

    Reply

  17. Hi Billy,

    I had read AFSK but cannot find lines of code relevant to D4 to D7. Can you pls explain a little further. Thanks!

    Reply

    • Thanks Billy

      I try to upload the sketch you provided with FTDI232.

      It gives the following upload error. How can this problem can be fixed?

      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0xd5
      avrdude: stk500_recv(): programmer is not responding
      avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xd5

      Reply

  19. Hi Billy,
    With GPS module, I use a module as GY-NEO6MV2. It works well with Arduino UNO.

    But it doesn’t work with Arduino Promini 3.3V.
    Can you pls suggest how to solve this problem? I noticed the model of GPS you used in your project. Wonder if any particular requirement is needed and alternative GPS meed the need of circuit.

    Thanks
    Robbie

    Reply

  20. Hi,

    Ensure that RX/TX are correctly attached and modem is on the correct speed, there is a fellow ham that reported that it Arduino promini works also this module.

    Can you try with the demo program of TinyGPS library ? If it works there it will work also with the APRS tracker

    Billy

    Reply

  24. hi. i load the code to arduino and i put it in pcb. nothing happend. i try to press the beacon button nothing again. any idea? thanks.
    73 SV7PKL

    Reply

      • το συνδεσα στο serial και οταν παταω το κουμπακι στο arduino μου εμφανιζει Arduino APRS Tracker. για να λειτουργησει πρεπει να βρει στιγμα το gps ή για δοκιμη δεν χρειαζεται?

      • i connect to serial and when push the button on arduino write “Arduino Aprs Tracker”. the gps must fix the sats to test the tracker?

  25. Hello, I saw that some friends had the same problem that appears to me. The altitude shows 1280m, when I am currently at 100m. For what is this? can it be corrected? Thank you

    Reply

  26. Hello, I saw that some friends had the same problem that appears to me. The altitude shows 1280m, when I am currently at 100m. For what is this? can it be corrected?
    Is the sending time between packets fixed, or does it vary according to the speed of movement?
    Thank you

    Reply

    • If you use the SmartBeaconing version the sending time of packets depends on your speed. As for the altitude difficult to explain/debug it, can you please send me two three lines of the serial output ?

      Reply

  27. Τελικά στέλνει μια χαρά με το BAOFENG. Άλλαξα το gps και δουλεύει μια χαρά. Μπορώ να αυξήσω το χρόνο εκπομπής επειδή το δοκίμασα με το vhf module SA828 και αργεί λίγο να ανοίξει με αποτέλεσμα να μη στέλνει όλο το πακέτο.
    73 SV7PKL

    Reply

  30. There is a significant bug in the NMEA conversion code that does not put a leading zero for longitudes less than 100. This causes the packet to be rejected or the position information not to display in most APRS decoders, including the Yaesu FTM-300, APRSIS and APRS.fi.

    I solved this by borrowing a NMEA converter routine from another project and changing the flat and flon variables to “long” from “float”, then calling the update lat/lon routine version written for long variable position variables. The new NMEA conversion routine also requires “long” position variables.

    I also removed the display routines for smaller code size and a less battery-hungry profile.

    Works fine now. The rest of the code is excellent.

    Reply

  32. Hello, We are building a CANSAT and trying to implement an APRS System for tracking it. I would like to know how can we do that using Arduino and how should whole System should be tracked from the ground station. would require some help.

    Reply

  34. HI,

    Thank you for your program it is wonderfull.
    Its works very fine.
    Now the question HI.
    You use pin 13 ( internal led ) for checking that TX is done. I would like this on a other pin pe pin 2 . I can’t find where i have to do this in the program .
    Can you help me?

    ’73 John

    Reply

  38. I followed all the breadboard schematic but I can’t get the module to trigger signal to my walkie. anyone can share the experience? GPS LED is blinking.

    Reply

  39. Hi Billy, I’ m planning to build a simple tracker and I found you project, which is exactly what I need to do that. Since I’m very noob in knwoledge to program Arduino, but I´m ok in electronics, I want to ask you if in your project it´s possible to retrieve the TX and RX data BEFORE they’re converted to audio AFSK, to connect it to a external modem IC (like the TCM3105, AM7910, etc) intended for more robust transmission. Have you and idea to do such that?
    Thank you very much in advance!

    Leandro
    LU8DOI

    Reply

  40. Hey ,
    I have read the pdf of TCM3105 but i don’t understand what is the expected input of TX (i assume analog but in what format ?)

    LibAPRS implements the AFSK modem in software , which means it needs a complete rewrite. You can have a look at AFSK_dac_isr (in LibAPRS/AFSK.cpp)

    What i am saying here is that if you can understand what is the analog input needed to have a proper APRS message it could be possible.

    73

    Reply

  41. Hi!
    Is there a way to specify how long into the 2 minutes the packet is started? So that several of these running on GPS time could be programmed to transmit at different times and avoid packet collisions?

    Thanks,
    Joe G0EVB

    Reply

    • Hey,

      I do understand the need but it is not implemented , ideally we should monitor the frequency and then decide if we should transmit or not.

      Its not random but it is 2 minutes after you got a GPS fix, you could add some randomness on the 2 minutes +- 10-15 seconds

      73

      Reply

      • Hi,

        Thanks for the response. Would that be achieved by altering line 97 to be e.g. 1.9 instead of 2?

        aprs_update_timer_id=timer.setInterval(1.9*TIMER_MINUTES, setAprsUpdateFlag);

        73 de G0EVB

Leave a Reply

Your email address will not be published. Required fields are marked *

*