OpenPulse - the first open source modular wearable

OpenPulse is a modular biosensor wearable built around a simple idea: people should be able to choose what their wearable measures, understand how it works and control their own data.

We are Mateo, Juan and Roman, a team of three school students working across hardware design, firmware, signal processing and business development. Since 2025, we have been turning that idea into real electronics, learning through PCB revisions, prototypes and testing.

The project started with frustration over subscription-based wearables and limited access to their underlying software and data. We wanted to build something we could understand, modify and improve ourselves. That became the starting point for an open, modular fitness band—and eventually a broader platform for companies, researchers and developers who need a wearable tailored to their application.

The core of OpenPulse is its interchangeable sensor modules, which we call “pucks.” Our current architecture combines a compact mainboard with two skin-facing sensor positions and one outward-facing position for environmental sensing. Each puck carries its own sensing electronics, allowing different configurations to share the same central platform.

This modularity is central to what we want to achieve. A research team could configure the device around the signals relevant to its study. A company could integrate a tailored wearable into its existing software. Developers could create new sensor modules and extend the platform. Replaceable modules also create opportunities for repair and upgrades, helping useful hardware stay useful for longer.

Our main focus today is a configurable B2B platform, with the potential for partners to offer OpenPulse under their own brand. Open software, accessible data and integration into existing applications remain central to the vision. We also want the platform to be useful to the maker and open-source communities that inspired us.

We already have physical prototypes and custom mainboards that we have manufactured, assembled and tested. We are now developing our third hardware revision, bringing the electronics, sensor modules and enclosure together in a compact wrist-worn design. The next stage is to validate the revised hardware and sensor integration, improve reliability and prepare devices for pilot projects.

Building something this small makes every design decision matter. PCB layout, component placement, power consumption, mechanical connections and contact with the skin all influence whether a promising design becomes a useful device. Access to MakerSpace Munich has helped us develop practical manufacturing skills, including PCB milling and pick-and-place assembly.

Along the way, OpenPulse earned first place in Europe at the Blue Ocean Student Entrepreneur Competition and reached the Top 5 in the Health category of STARTUP TEENS. Those milestones encouraged us to keep building; our focus now is on making the hardware ready for meaningful use.

As a student team funding development on a tight budget, each manufacturing round is a significant investment. Support from PCBWay with PCB fabrication and assembly would help us build the next prototype batches, test improvements and progress toward pilot-ready hardware.

We would be happy to share that journey with the PCBWay community through project updates, build photos and practical lessons from designing and assembling compact modular electronics. Our goal is to build a platform that others can understand, adapt and help improve—and to show how far a student team can take an idea by building it.

BOM is very technical and features many parts that are not clear by name so it’s not provided. If needed/wanted it can be provided.