Some time ago I have decided that i need a APRS Tracker. But instead to buy one i have decided to build one myself.

I have started to research the internet for some ready solution and i came across a post from DB1NTO posted here.

I really like the idea and started to experiment. I have found that Mark (the owner of the side) has manage to write a Arduino library for APRS. And because i really like the open hardware and open software i decided that i will base my design on Arduino.

The hardware was ready really quick. Here is the circuit diagram that i designed. APRS_circuit

There is nothing complex about the hardware design. I have used DORJI818V module for transmit and receive aprs packages, 0.96″ OLED display to display some information and received packages. The processor i used is ATMEGA328. I have also added charging circuit for the 3.7V battery and a transistor to switch the PTT of the transmitter.

Here are some photos of the ready board.

IMG_0082 IMG_0081

The hardware part was the easy one. The next couple of weeks i was busy to write the software part. (Don’t laugh, I’m not a very good programmer).

At the beginning i have tried to add in the sketch to many things and the program always crashed. I have some success at sending packages but the receiving part was the problem one. But at the end and whit the help of some really nice guys i have manage to do it. In the sketch is included “smart beaconing” function. The tracker sends packets in different time periods depending on the speed, distance and direction change of the object.

Here is the working version of the sketch. Sketch.

Now the tracker sends and receive messages whiteout any problem. I have successfully tested it on my work travels and it works fine.

There are some more things that i want to add and some part of the code still need optimization, but for now I’m very happy whit the tracker.

Here is one similar project made by Stanly – 9W2SVT from witch i have taken many ideas for my skatch.


Arduino APRS Library

U8glib Library

TinyGPS++ Library

By lz1ppl

15 thoughts on “Micro APRS Tracker”
  1. Cool Project!
    Where did you get the tiny male sma antenna? Is it specifically for the 2 meter band? Thanks.


    73 to All!

    1. Hi Andy,
      This is not an antenna. This is just rg58 coax that connects the tracker whit my Diamond X50. As a portable antenna i use Diamond SRH-815S.

      73, de LZ1PPL

  2. Здравейте Пламен,
    много ми хареса Вашата разработка за APRS Tracker.
    Бих Ви помолил, ако е възможно, да ми изпратите чертежите на платката.
    Желая Ви много здраве и нови успехи.
    Благодаря предварително.
    С уважение.
    Сашо – LZ3OG

    1. Здравей,
      Извинявай че чак сега виждам коментарът.
      Схемите са изпратени на твоят e-mail.

      de LZ1PPL

  3. Hi. I tryied your schematics. Everything seems OK to receiving, some problems at decodeing MicE but overall, is OK.
    But, no Tx!
    Searching into the code, I didn’t see where is the Digital 3 (PTT) defined! Is this intended? :-))

    73 de Adrian, yo3hjv

  4. Hello Plamen!
    Thank you for sharing your project, schematic and sketch.
    I built it on Arduino Nano with VK2828U7G5LF TTL Ublox GPS module, withkut PTT (I’m using VOX feature of Wouxun KG-UV2D). TX is working properly, RX not tested.
    Only the S3 (Digital 8) switch for instant send is not working or is not defined.

  5. Hello, I have a problem: The longitude is to be sent as: 00811.00E. It is only sent: 0811.00E. Unfortunately, my knowledge is not enough to change this.
    I ask for help . Many Thanks ! Peter DL1EEM

    translated by Google

  6. Hey to all, I have the following problem: the coordinates should be so 00811.55E. But it is only sent: 0811.55E. How do I get the second 0 (zero) in the program. Unfortunately my knowledge is enough to correct this.
    Many thanks peter dl1eem

    translated by Google

  7. Hello Plamen,

    Sketch works great !
    All without any issues from the start, super,,

    Just curious, does it also display incomming packets on the OLED ? or just on the serial monitor ?


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    Thank you for the post. I will definitely return.

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