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.
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.