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).  You can also use a NEO-6M and change the appropriate define on the code

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

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 and now is the default

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/

PCB

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

https://github.com/billygr/arduino-aprs-tracker/tree/master/archive/PCBv1%20KiCad%20(5.0.2)

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
1 x 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
1 x TP4056

Bill of Materials (PCB version)

Includes the 18650 socket+TP4056

https://github.com/billygr/arduino-aprs-tracker/tree/master/archive/PCBv1%20KiCad%20(5.0.2)