User Testing in Electronics: How it Helped us Engineer a Better Orbyt Ring

User testing is often seen as the final checkpoint in electronics development - but in reality, it's where true engineering refinement begins. While simulations, lab tests, and ideal conditions help get a product off the ground, only real-world usage reveals how electronics behave in the hands of actual users. In this blog, we take you behind the scenes of how user trials exposed critical design flaws in comfort, charging, durability, and PCB reliability - and how we systematically fixed them. For engineers building hardware meant to be worn, used, and trusted daily, this case study offers a powerful reminder: user testing isn’t just a validation step; it’s an engineering tool.

---

Photo by UX Indonesia on Unsplash

Why User Testing Is Fundamental to Engineering Smart Wearables

There’s a common belief in hardware that once you ship a prototype, the toughest work is done. But if you’re serious about product quality, and especially if you’re designing something people wear every day - that’s when the real work begins. Unfiltered, factual insights come when a product leaves the safety of test benches and enters the messy unpredictability of daily life.

At Sensio, we’ve come to treat user testing not as a final validation step, but as a deep diagnostic phase - where real people unknowingly become your most honest engineers. Their lived experience with the product unearths friction points that specs and simulations often miss.

When we took Orbyt v8 to the field, we were cautiously optimistic. It had all the right specs on paper. But what we learned from actual users redefined how we approached engineering.

The 4 Big Problems We Had to Solve

Rolling out Orbyt v8 to a controlled group of early testers revealed crucial pain points we couldn’t have discovered any other way.

1. Discomfort from the Interior Finish

The first feedback came as a surprise: several users told us the ring was uncomfortable after wearing it for more than a few hours. Some even removed it midway through the day. For a device that’s supposed to be “always on,” this was a dealbreaker.

Upon inspection, we found the issue was in the material and process used for finishing the interior surface. It wasn’t rough to the touch - but subtle imperfections were noticeable over time.

The fix? We switched to a superior finishing technique and adjusted our material source. This change also improved the ring’s manufacturability, which became critical during our scale-up runs.

2. Device Reliability and Battery Protection

During water-resistance and sweat-resistance tests, we saw inconsistent performance across devices. A few rings even shut down unexpectedly. After multiple rounds of debugging, the issue turned out to be exposed battery traces that were sensitive to moisture. Sweat was triggering minor shorts and creating slow battery drain.

We completely rethought the battery protection architecture. By better integrating our ICs and sealing the vulnerable areas on the PCB, we extended battery life significantly. This resulted in better durability, zero power leakage and more consistent performance across units. Here, user testing revealed a hidden circuit-level flaw - one that our lab humidity tests hadn’t caught.

3. Unreliable Charging Dock

Charging failures can often be confused for battery issues - but we traced the problem to our dock. Some rings charged inconsistently, while others didn’t connect at all.

After tracing logs and teardown analysis, we found that one of the ICs in the charger wasn’t supplying stable current. The dock’s alignment tolerances were too tight, i.e., if the ring wasn’t placed just right, charging failed.

To fix this, we added a secondary IC to regulate power delivery. We also redesigned the dock's mechanical layout to ensure correct alignment every time.

4. Workout Limitations

Users who wore Orbyt during strength training or yoga complained that the ring got in the way - especially on fingers that bent or made contact with surfaces. They didn’t want to stop tracking, but the form factor wasn’t cooperating. This wasn’t a failure of tech, but of contextual wearability.

Instead of forcing a one-size-fits-all model, we leaned into our differentiator: multi-site wearability. With minor tweaks to the algorithm and design, Orbyt became a ring that could be worn not just on the finger, but also on other locations of the body during workout. This dramatically improved usability without affecting performance.

Parallel Engineering Improvements

While user testing gave us essential signals for comfort, usability, and real-world durability, it also prompted a broader engineering sprint. Several internal improvements were made in parallel- not because of user complaints, but because we knew we needed to raise the bar for reliability, manufacturability, and cost-efficiency before scaling.

PCB Assembly: Debugging at Scale

One of our biggest learnings came from preparing to scale: making 10–20 units in-house is one thing; making 200 units with a vendor is another. We aimed to improve PCB yield through data. But most vendor-supplied data was inaccurate or incomplete. So, we ran our own in-house experiment - assembled 8 v8 PCB and documented every step of the process, from paste printing to final inspection.

Here’s what we found:

• The PCB edges were slightly sloped (a ‘taper’), which made it difficult for certain components to solder correctly.

• The PCBs didn't sit evenly in place, which meant the solder paste wasn't applied correctly.

• The boards expanded a little as a result of being heated multiple times. This tiny change made the stencils (used to apply solder paste) slightly misaligned, leading to poor soldering.

These may sound like small issues, but in smart ring manufacturing, even a difference of a few hundred microns (a fraction of a millimeter!) can cause massive failures.

After identifying these issues, we redesigned both the stencil and the pallet to compensate for the mechanical inconsistencies. With these fixes, we were finally able to push v8 to an 80% yield on a batch of 68 PCBs - significantly better than before, but still not where we needed to be.

Armed with these insights, and incorporating suggestions from our assembly partners, we made deeper design changes to improve manufacturability and reliability. We fabricated a larger batch of 200 PCBs and assembled the first 50 for testing.

That’s when we hit two new issues:

• The current consumption was nearly 10× higher than expected.

• The PCBs stopped working as soon as the programmer PCB was separated from the ring PCB.

After a detailed analysis, we traced the root causes to:

• Suboptimal placement and insufficient value of decoupling capacitors on the new PMIC - The older PMIC tolerated the previous configuration, but for the new, highly integrated PMIC, it was not sufficient despite being from the same family.

• No stitching ground vias in the ring PCB area - It existed only on the programmer PCB, so once it was separated, the top and bottom layer grounds were isolated.

To fix these:

• We managed to solder 0402, 22uF capacitors in place of 0201, 4.7uF capacitors. This gave the PMIC sufficient capacitance to start functioning reasonably well. Instead of 10x increase in the current consumption, it became a 2x increase in the current consumption which was usable.

• We managed to solder across Layer 2 and Layer 5 grounds where the programmer PCB detaches, restoring a unified ground reference.

With these patches, we finally had stable, usable PCBs - and the foundation we needed for a reliable v9.

BoM Optimization: Cutting Cost Without Sacrificing Quality

We needed to reduce cost-per-unit to scale profitably. We revisited every component on our BoM and asked: “Is this the best value for what we need?”

By validating cheaper alternatives for sensors, passives, and ICs - without compromising specs - we reduced costs by nearly 20%, which has long-term implications for margins and scale.

Charger Redesign: Fixing the Tolerances Trap

The original charger looked great, but was hard to produce consistently. Form had overtaken function. We identified two key manufacturing issues:

• Several parts needed to snap together, but the fit was too tight, making it hard to build them correctly every time. In manufacturing terms, the tolerances - or the allowed range of variation in a part's dimensions - were extremely tight. This meant even tiny differences in size could cause issues with assembly or function, leading to parts not fitting together reliably.

• Transparent components, while visually appealing, were also extremely difficult to produce within these strict tolerances, resulting in high rejection rates and low manufacturing yields.

To fix this, we redesigned parts of the charger to improve the fit and eliminate the need for transparent materials altogether. We simplified the geometry and improved snap-fit tolerances to allow easier assembly.

With multiple rapid prototypes, we found a version that balanced function, manufacturability, and cost.

The Outcome: A Ring Built on Listening

Orbyt v9 is lighter, more durable, and more comfortable. But beyond the specs, what makes it special is what shaped it: the voices of our users. Every bug, every edge case, every assembly error taught us something we couldn’t have learned otherwise.

When people talk about user testing, it’s often in the past tense - as if it’s a checkbox you tick before shipping. But at Sensio, we’ve found the opposite: testing is where the engineering really begins. User testing showed us what to fix. Internal engineering showed us how. Building hardware is hard - but building hardware with users in the loop is how great products come to life.