Open GPS Turns an ESP32-S3 Into a Buildable Golf Shot Tracker
Open GPS records club choice and GPS shot distances, then exports round data as CSV or GeoJSON. Its hardware, firmware and enclosure files are available to build.
Open GPS gives golfers a way to measure shots and keep their round data in files they can inspect and reuse. Built by maker and golfer Coleman Rollins, the handheld tracker combines an ESP32-S3, GPS hardware and a one-dial interface. Its appeal is practical: the project covers both the device and the build materials, from Arduino firmware to a printable enclosure.
That makes it useful for two audiences. Golfers can collect distances and club choices without relying on a proprietary tracker or subscription, while electronics makers can study how a compact positioning device handles input, location recording and data export. The project files and assembly instructions are available on GitHub.
Two location marks make a shot record
The workflow is simple enough to use between shots. Select a club with the rotary dial, click to mark the ball’s starting position, and take the shot. At the new location, click again. Open GPS records the second position and calculates the distance between the two GPS coordinates, displaying the result in yards.
That method gives each measurement a clear basis: the device compares two recorded locations. It also means the result depends on the positioning data it receives and on the golfer marking the positions at the right times. The article describes the GPS board as providing meter-accurate positioning, but it gives no on-course accuracy results or comparison with dedicated golf equipment. Anyone evaluating measurements for detailed club analysis will want to see how the device performs in their usual playing conditions.
Club selection is part of the record, rather than an afterthought. With the chosen club saved alongside the shot, exported data can help a golfer review which clubs were used and how far individual shots traveled. The usefulness of that record depends on consistently choosing the correct club and marking both locations; the device automates the distance calculation, while those inputs still come from the player.
Built around accessible components
A SparkFun Thing Plus ESP32-S3 runs the Arduino firmware and coordinates the device’s functions. A SparkFun GPS Breakout - NEO-M9N supplies the positioning data used for the distance calculation. Rollins also uses a 1.3-inch Qwiic OLED display and a Qwiic Twist rotary encoder.
The display and encoder keep the interaction focused: menus, club selection and shot recording can all be handled through one dial, with the screen showing the relevant information. For a handheld device used outdoors, that is a straightforward design choice. It avoids requiring a phone interface for each action and keeps the physical controls limited to a compact display and rotary input.
The parts connect through SparkFun’s Qwiic ecosystem, using cables for the signal connections instead of requiring the builder to solder each one. That can lower the barrier for assembly and make it easier to connect the modules, though the project still involves putting together the electronics, programming the board and fitting the parts into an enclosure. The project also points to other GPS/GNSS breakout boards as possible alternatives. A different board may change the build’s cost or positioning behavior, so compatibility and configuration are worth checking before swapping components.
Local records, portable hardware
Shots, including their starting and ending coordinates, are saved on the device. After a round, the golfer can connect it to a computer over USB and export the records as CSV or GeoJSON. CSV is suited to spreadsheet-based review, while GeoJSON can represent the locations as geographic data for tools that support that format. Keeping the coordinates alongside the calculated distances gives users more to work with than a list of yardages alone.
The project uses a rechargeable lithium-ion battery and a custom 3D-printed enclosure. The source does not give battery runtime, device dimensions or a parts cost, so those are details builders will need to establish from the build materials and their own assembly. Likewise, it does not describe wireless syncing or an accompanying app; the documented export path is a USB connection after play.
What builders can inspect
Open GPS is more than a parts list. Its GitHub project includes Arduino firmware, 3D-printable enclosure files and instructions for assembly and programming. That gives builders a route to inspect how the device works and adapt it, subject to the project’s implementation and the hardware they choose. The source also provides a full build video and a parts wishlist.
For a golfer who wants shot records in accessible file formats, the central value is control over the build and its data. For a maker, the project is a focused example of GPS, embedded firmware and a physical interface working together. Before treating it as a precision instrument, check how well its location readings match your needs on the course. The next useful details for builders would be measured battery life, on-course distance results and notes on substituting GPS modules.
SparkFun’s affiliate program is also mentioned in the source project page for makers who publish their own projects. The page includes an image linked to that program:
