Grove - A9G GPS/GPRS sensor module

Introduction

While searching for an appropriate sensor for my collaboration with Seeed Studio in its Co-invent campaign, I stumbled upon the AI thinker's A9G GPS/GPRS module and was fascinated by its features.

So I decided to create my own Grove sensor using its versatile features. In this blog post, I'll share my journey of designing and building a Grove sensor using the A9G module and Seeed Studio's Fusion services. You'll learn about the hardware components I used, the steps I took to assemble and connect them, and the testing and troubleshooting process I went through to ensure optimal performance.

Whether you're interested in building a similar device or simply curious about the possibilities of the A9G module, I hope this post will provide valuable insights and inspiration for your own electronics projects.

Design and Build:

AI Thinker already has a development board based on A9G module, where all the peripherals are populated for usage. I used this development board as a reference to create my design. Since Grove sensors come in its unique footprint sizes (20x40, 40x40,..) I just had to compare which fits the best with the module, Since A9G itself is of 18x18 mm, I finalized 40x40 Grove size.

I design all my PCB projects in Altium Designer, for this project I created the schematic based on AI Thinker's development board, while eliminating parts that are not required, to create a bare minimum configuration.

The PCB is of 2 layers, with via shielding added to high frequency tracks. All the connectors are on top surface while SD card slot and SIM card connector is on the bottom.

Usage:

The A9G module stands out among other GPS modules due to its impressive array of features, with a particular focus on its GPRS functionality. In this tutorial, we will delve into this unique capability.

Many projects in today's world require internet connectivity for tasks such as MQTT pub-subs and HTTP REST APIs. Typically, this necessitates the use of a microcontroller that supports Wi-Fi connectivity, like the ESP32 series. However, relying on an existing Wi-Fi network becomes problematic when working in outdoor environments where such networks are unavailable. This is where the A9G module proves invaluable, as it can bring internet connectivity on-board directly by utilizing a SIM card and nothing more. By connecting to a GPRS network, it empowers users to carry out dedicated MQTT or HTTP calls seamlessly.

To illustrate the practicality of this module, consider the following example:

HTTP Get API call to a ThingSpeak channel - Any sensor data can be sent to the channel to monitor.

AT - commands used in this example are:

AT+CGATT=1

AT+CGDCONT=1, "IP", "CMNET"

AT+CGACT=1, 1

AT+HTTPGET="http://api.thingspeak.com/update?api_key=NO4RI92UAFMTOJVG&field1=0"

By harnessing the A9G module's GPRS functionality, developers can now access internet services without depending on traditional Wi-Fi networks, making it a game-changer for various applications. Whether it's sending MQTT messages or making HTTP requests, the A9G module offers a comprehensive solution for projects that demand reliable internet connectivity in outdoor settings.

Applications:

One of the remarkable features of the A9G module is its ability to run MicroPython, transforming it into a self-contained system combining internet connectivity and GPS functionality. In this Grove Design, With convenient access to firmware upgrade UART pins, users can easily update the firmware to enable MicroPython compatibility. Furthermore, the board is equipped with an SD card slot, allowing for the logging of GPS sensor data. This makes the Grove - A9G GPS/GPRS module a versatile standalone DataLogger. This opens up possibilities for asset tracking, vehicle navigation, or even location-based services in various industries.

Limitations:

The A9G module, despite its impressive features, does have a few limitations worth noting. Firstly, it requires a SIM card that supports GPRS network bands, which may not be available from all network providers. Additionally, proper network range is necessary for optimal operation. Moreover, GPS functionality relies on a dedicated antenna and can only be effectively used in outdoor environments. It is important to mention that GPS location data may not always be obtained even when outdoors, as it was the case in my experience. These limitations should be considered when working with the A9G module to ensure its optimal performance.