EYTraker V9 LTE:                                    1 May 2024

Introduction

The original EYTraker was first introduced in 2006 and has since then been through a few iterations and redesigns based on new platforms and technology. I will do a writeup on the evolution of the design in the near future.

The latest revision of the EYTraker V9 is based on the SIMCom Cat 1 LTE/GPS engine A7670E module that is available from Makerfabs as a complete voice and data LTE solution. The unit also features a SAMD21 low-power microcontroller using the 32-bit ARM® Cortex® processor with power and battery management included. The compatibility of this microcontroller with Arduino IDE makes it ideal to develop a robust tracking system. The previous EYTraker designs were based on the GSM 2G network that has since become oversubscribed and unreliable with even indications that the 2G networks will be decommissioned to free up frequency spectrum for 4G. The new unit is fully LTE or 4G capable that increases the tracking reliability of the unit.

Apart from a few external components, the unit requires very little additional changes to allow it to function as a stable tracking platform. The features of the EYTraker V9 includes the following:

·         5V supply via the USB-C connector with a LM2596 used to ensure a wide range of input voltages.

·         Ignition voltage sense + Ignition status

·         LiPo Battery and USB Bus voltage sense

·         Accurate GPS positioning + max speed per sector

·         Hourly engineering data payloads to APRS

·         Internal unit temperature

·         Full Watchdog and hard reset in software to ensure reliable online time

·         Functions with MTN or Vodacom SIM cards

The design of the EYTraker V9 is based on off-the-shelf components that allows for quick configuration of the unit. The basic design is based on the A7670E module PCB and a LM2595 buck boost converter set to 5V feeding the USB-C connector. A small 3.8V 800mA LiPo battery provides about 2 hours of backup power in case of a power disconnect. There are 2 status SMD LEDs with current limiting resistor (330 ohm), on Pin D8 and D9, that show the status of the tracker at any given time, a jumper on D13 for hard reset in software and the ignition sense with a voltage divider (220K and 1M resistors) and smoothing cap (1 uF) on pin A0.

A very simple design supported by stable firmware on the SAMD21 that has been tested extensively.

The unit is housed in a plastic enclosure (110mm (L) x 60mm (W) x 24mm (H)) with an external power connector, GPS SMA pigtail and GSM SMA pigtail to allow the connection of external GPS and GSM antennas. The option exist to use an internal GPS antenna if required. The complete unit draw 80 mA on average.

A black box with red and black electronics

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Although the unit firmware is open source, it is not freely available due to the risk of access of non-amateur users to the APRS network. I will only share the Arduino IDE format firmware via email and if your amateur radio callsign is confirmed.

A screenshot of a computer

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The unit connects to the South African APRS-IS server at  http://www.aprs-za.com:14501 with full position reports and engineering data available at aprs.fi.

Please send me an email if there are any questions or you want a copy of the firmware.

73, Hennie, ZS6EY