Gps testing board

GPS Development Board - ANTENOVA M20050-1 and ATGM332D-5N31

A KiCad breakout board for evaluating two GPS modules side by side — the ANTENOVA M20050-1 and the ATGM332D-5N31 — plus two footprints for 20 mm coin‑cell holders to keep the module's backup RAM / almanac powered for a warm start.

Context

This is one of the breakout boards made for the EJA "Intelligent Popup Buoy" project (2021 Hackaday Dream Team). Each candidate part for the EJA M board was first tried on a small dedicated PCB. Both GPS modules speak plain NMEA over UART and are wired to identical header pinouts here, so the same ESP32 firmware runs against either one. The ATGM332D-5N31 was the module chosen for EJA M.

Table of Contents

1. Schematic
2. Bill of Materials
3. 3D Model
4. Firmware and Testing
5. Repository Layout

Schematic

ANTENOVA M20050-1

ATGM332D-5N31

Each module has a decoupling capacitor, a U.FL connector for an external active antenna, a coin‑cell backup input, and UART / I2C / IND (fix indicator) broken out to headers.

Additional Coin Battery Holders

Two 20 mm coin‑cell holder footprints (a Linx BAT-HLD-001 retainer and a Keystone 1066 open holder) so the mechanically better one can be picked for the buoy.

Bill of Materials

A machine-readable BOM is in gps-testing-board/gps-testing-board.csv.

3D Model

Firmware and Testing

Firmware/ has an Arduino sketch for each module (esp32_atgm332d/ and esp32_antenova_m20050/). Both are the same code with a different banner; only one module is exercised at a time.

• The ESP32's Serial2 runs at 9600 baud on GPIO16 (RX) / GPIO17 (TX), wired to the module's UART header.
• The FuGPS library parses the NMEA stream. The sketch asks the module for RMC + GGA sentences (FUGPS_PMTK_API_SET_NMEA_OUTPUT_RMCGGA).
• When a fix is available it prints fix quality, satellite count, HDOP, altitude and a ready‑to‑click google.com/maps link with the current latitude / longitude; if the module goes quiet for ~10 s it prints a "not responding" warning.

Wire the module header to the ESP32 (VIN→3V3, GND→GND, TX→GPIO16, RX→GPIO17), fit an active antenna on the U.FL connector, open the matching sketch in the Arduino IDE (ESP32 board support + the FuGPS library installed) and watch the serial monitor at 115200 baud. A first fix outdoors takes a few minutes cold, seconds warm with the backup cell fitted.

Repository Layout

README.md
LICENSE                              Apache 2.0
Schematic v1.0.pdf                   exported schematic
Images/                              schematics, 3D renders, board photos
Firmware/
  esp32_atgm332d/                    Arduino sketch, ATGM332D-5N31
  esp32_antenova_m20050/             Arduino sketch, ANTENOVA M20050-1
gps-testing-board/                   KiCad project
  gps-testing-board.pro/.sch/.kicad_pcb
  gps-testing-board.csv              BOM
  Symbols/ Footprints/ 3D/           project-local libraries
  Gerber/                            fabrication output
  Exports/                           STEP model