(If you missed some of the adventure, or just want a recap – catch up with Part 1, Part 2, and Part 3!)

In just four weeks we turned our innovative idea into a reality, and that’s really what we do here at Root3 Labs! This project enforced for us some important lessons in product development and device design. It was clear that our success came down to three key things:

• Prioritizing Ruthlessly: Focusing on the Minimum Viable Product (MVP) allowed us to achieve core functionality within a tight time frame.
• Close Cross-Disciplinary Collaboration: Seamless, close (and we do mean close!) communication between each discipline involved ensured everyone was aligned and always working towards the same goals.
• Mastering the Timeline: With such a tight development window, every day really does count!

These are tools that we use in every project, and you probably do too! But, having to pare everything down to their bare essentials allowed us to pay attention to what are the strategies that help us achieve a successful outcome.

Given the tight timeline, identifying the critical path was the first and most important step. We knew there would need to be electrical, mechanical, and software components involved in the overall design. In order to meet the deadline, each team would have to work in parallel with close collaboration.

While in-house fabrication would greatly reduce lead times for mechanical components, the same would not be true for the Printed Circuit Boards (PCBs). We can populate boards in-house, but we currently outsource bare board PCB fabrication. Although the turnaround time was rapid – as little as five days – it would still be our biggest bottleneck in terms of time. This meant that PCB design and fabrication would emerge as the Critical Path for the project.

We determined that we wanted to order the boards by the end of the first week to leave enough time to receive, populate, and test the boards before final assembly. Recognizing the need for early PCB ordering, we aimed to solidify features, identify components, and finalize the board design within the first week. This necessitated a collaborative effort: the electrical team selected components while the mechanical team defined component footprints. These efforts converged to finalize the design. The remaining tasks also had tight timelines, but without ordering and receiving the boards on time, we would not have met the final deadline.

Besides identifying the critical path, we allocated the most time for the design of the device – both electrical and mechanical. We didn’t have time for multiple physical iterations, so it was essential to “measure twice and cut once” by spending the required time in the design phase. Even with our attention to detail, we still had to come up with creative ways to solve design issues – take a look at “Hand Wiring a Fix” in Part 2 of our blog series. Thank goodness we love hard problems!

We always work together closely (it’s not that big of a workshop!), but it was a tactic that definitely paid off with this project. The early electrical and mechanical design was boosted by the fact that Christina, the mechanical lead, and Chris, the electrical lead, happen to share an office. That means instant updates between ‘departments’ as the design progressed. Of course, it was just as simple to get input from the software and fabrication ‘teams’, as well. Chris or Christina would just have to walk an extra few feet down the hall!

Our MVP for this badge was a fully finished badge with an interactive screen, and the potential to evolve. We included the EKG and pulse oximeter sensors on the PCB and the stainless-steel thumb contacts to provide an easy path for development. Once included in the design, we knew we could work on the software development and UI later, so we did not include displaying the data as part of our MVP.

Initial software and UI development focused on displaying a contact card for the user wearing the badge. This deliverable closed the loop on the basic functionality to demonstrate the electrical, mechanical, and software components were all working together at a basic level. Although it’s tempting to dive down the rabbit hole into the more interesting features, we maintained focus on building a strong foundation with the MVP. This allowed us to stay on schedule and left room for development after MEDICA.

Since MEDICA, the badge has made several appearances at networking events. In parallel, our software team has been focusing on collecting and displaying heart rate data. Currently, we can collect raw sensor data showing a waveform from the EKG sensor. We then filter it and process it to reveal the dominant frequency – aka the heartbeat. The next step for this will be to create the UI elements to display this data.