Most evenings, as we head home, the matatu drivers by the local footbridge wave at us. Just a quick nod or a smile, the kind of small gesture that slips quietly into your routine until one day, you realize it means something. That maybe you’re no longer just passing through.

This week, that feeling crept into more than just the journey home. Between testing low-cost electrodes, 3D printing wearable casts, and chasing down clean EMG signals, that sense of rhythm kept showing up – in soldered circuits, in shared coffees, and in all the in-between moments that are starting to feel a little more familiar.

Building the Active Cast One Snap at a Time

Our host-site project has taken shape – quite literally – over the last two weeks as we have worked with our colleague Waka at the design studio. The project focuses on designing a low-cost, wearable cast that can actively prevent muscle atrophy by stimulating muscles. The idea grew from conversations about the limitations of traditional immobilizing casts, especially after sports injuries, where muscle loss during healing can lengthen recovery time or limit function.

We began by debating the method of stimulation: PEMF (pulsed electromagnetic field) vs. electrical stimulation via electrodes. PEMF sounded great in theory, but sourcing components locally, cost-effectiveness, and simpler hardware pointed us toward electrical stimulation as the better fit for our context. So, we’ve been designing this circuit for the past two weeks. After finalizing the waveform we wanted (a biphasic square wave to avoid tissue damage), we coded the signal and started wiring the motor drivers and timing components. 

At one point, we accidentally burned through an Arduino board (RIP) – turns out, feeding it more than 22 volts is not a good idea! It also seemed like our multimeter wasn’t picking up the needed output voltage. Some troubleshooting later, we decided to go simple and test the output with LED lights instead… and it worked the whole time, the biphasic output was just too fast to be picked up by our multimeter. Classic. We’ve since cleaned up the design, confirmed the signal on an oscilloscope, and are looking into integrating this model into our cast design! 

Alongside electrical stimulation, we have also been building an EMG sensor (trying to capture real-time voltage signals from muscle contractions) so users can track muscle loss or gain over time. Early testing involved low-cost DIY electrodes made from washers, salt packets from the cafeteria, and hand soap instead of conductive gel (you can’t say we haven’t been getting creative!). At first, we struggled with inconsistent readings, and the op-amps available here weren’t ones we’d worked with before. 

Eventually, we rebuilt our differential amplifier, fine-tuned our reference voltage, and celebrated when we finally got readable signals on the oscilloscope!!

We then moved to designing the physical cast. Our first prototype was a flexible, single-piece sleeve with built-in slots for electrode placement meant to accommodate a variety of hand sizes. But once printed, the structure was too thin to offer any real support, and the electrode holes warped easily. So we pivoted.

We redesigned the cast into a two-part model that snaps together, giving it more rigidity and making it easier to print with more precise dimensions. This version has honeycomb-shaped inserts for electrodes and added thickness along the wrist to stabilize weak areas. It’s still moldable, but should hold up as we do further testing. We’re now going to start thinking about integrating the EMG sensor, the electrical stimulation circuit, and the cast together as one model. 

From Sound to Signal: Troubleshooting the Digital Fetoscope

In parallel with our active cast work, we’ve also been steadily building and refining the digital fetoscope. It’s been a process – writing code, testing filters, debugging hardware – but we’re starting to see clear, consistent signals.

We started troubleshooting last week with the basics: looking into the microphone, op-amp amplification, and a bandpass filter tuned to around 20–200 Hz. The first few days of coding were a lot of long hours. Our base Arduino code was noisy, and attempts to filter it either flattened the peaks or lagged too far behind to be useful. The turning point came when we started experimenting with Hilbert transforms in MATLAB, which helped us visualize the signal’s energy across both time and frequency. The heartbeats were starting to stand out more clearly.

Once we had that working offline, we started translating parts of the logic back into Arduino-compatible code. On Friday, we finally hit a breakthrough: the fetoscope began detecting beats per minute in real-time. The bandpass filter was comparatively stable, the peak detection consistent, and we could finally see those satisfying spikes when we played heartbeat audio near the mic. Progress!

Next up, we’re trying to re-incorporate a wavelet transform to denoise the signal more precisely, now that the base is stable. The hope is to preserve the heartbeat peaks while scrubbing out ambient and mechanical noise, especially from the mic, which keeps mysteriously losing sensitivity. We’re now on the hunt for a mic that can handle a wider frequency range – easier said than sourced, especially low cost. But hey, I love a challenge. Add it to the list of things I’ll be thinking about at 2 a.m. 

Back in the Field: Device Testing + Meetings

Last Wednesday, we delved deeper into our work with the Rice360 devices we brought with us, including the Endometrial Biopsy (EMB) trainer I helped develop back in Houston! It was surreal unboxing it here in Nairobi, where we’ll be testing it with clinicians for real-time feedback. We assembled the magnetic components, checked each tissue insert, and finalized the evaluation surveys for both this device and the neonatal gastroschisis bag.

Later that week, we met with Dr. George Okello, Rice360’s country lead, and his wonderful team. We coordinated clinician visits and feedback sessions with OBGYNs and pediatric surgeons. Sitting in that meeting, I had a moment. This is what I’ve always dreamed of: traveling, learning, and building solutions with real-world impact. And now, I’m in a room where it’s actually happening.

After the meeting, we took a short walk to the Java House down our street – a spot that’s quickly become part of our routine. Over spiced Malindi macchiatos (giving my homemade chai a run for its money!) and a Nairobi breeze strong enough to scatter our napkins, we caught our breath. Everyone was chatting, laughing, and checking in. Our days no longer feel new or uncertain. The same familiarity as the drivers on the footbridge seems to creep in here as well. 

Of Lions and the Coast

Over the weekend, we visited Nairobi National Park, where I saw lions nap beneath speeding trains and ostriches share space with the city skyline. It was a wild juxtaposition, and somehow, it made perfect sense. The edge between city and savanna felt thin, like a reminder that nature and structure can (and do) exist side by side. I’ve found that this feeling echoes throughout Nairobi itself. The city’s architecture feels like freedom: colorful, varied, and full of personality. It’s a city that doesn’t try to look the same, and it’s all the more alive because of it. This energy pulses through places like the Maasai Market – a rotating open-air bazaar filled with vibrant textiles, hand-carved jewelry, and bold paintings. Just walking through it feels like stepping into a palette of Nairobi’s creative spirit.

And just when I thought I’d seen the full range of contrast and color, we arrived in Mombasa.

The plan was simple: take a train to the coast for a weekend of rest and exploration. The reality? All the train tickets were sold out. That wasn’t going to stop us, though. After a sleepy 5:30 a.m. start, we pivoted fast, rerouting through flight bookings at the station and somehow still finding time to stop by the Giraffe Centre, where we fed a three-month-old baby (yes, it was adorable).

With a couple of hours still remaining before our flight, we found ourselves sitting under sun-dappled trees at Cultiva, a farm-to-table spot with amazing brunch and a few wandering cats for company. My aunt, who worked in Nairobi for a year, has been giving us the best food recs!! And then – one flight delay and a 90-minute drive from the Mombasa airport later – we finally made it to Diani Beach just in time for the Summer Tides Music Festival.

That evening, we met up with our fellow Rice CCL interns and local friends, caught some incredible music right on the sand, and found new artists to obsess over (Mutoriah and Nikita Kering – highly recommend).

The next morning, we took the ferry into Old Town Mombasa, which was a maze of coral stone buildings, carved wooden doors, and ocean air thick with salt and spice. As we wandered through the narrow streets, I struck up a conversation with a computer science student working at Nyali Beach for the summer. A few steps later, just outside Fort Jesus (a 16th century Portuguese Fort), a welding technician was crouched beside the road, carefully shaping metal into ornate hinges for a carved wooden gate.

There were sparks flying in the open air, the hum of tools blending with the call to prayer in the distance. It made me smile – we’d had a go at welding joints during the summer program, but seeing that level of precision in action was something else entirely.

Closing the Loop

These past two weeks, our fetoscope picked up real beats, our circuits pulsed in square waves, and we squeezed in some adventures along the way. We made progress in code, in conversation, and in the quiet moments in between.

Each evening, we cross that same footbridge – the one where the matatu drivers now nod as we pass –  and return to a place where our neighbors smile and wave. A place that feels a little more like home. What began as unfamiliar is starting to take shape in the form of the patterns we’re slowly becoming part of. One familiar moment at a time. 

Signing off from our little corner of Nairobi,
Saumya 🏙️⚙️

It’s hard to believe that I’ve already hit the halfway point of my time in Nairobi.

The rustle of fig leaves in Karura Forest.
The sound of a heartbeat through a Pinard horn.
The low growl of a lion carried across the Maasai wind.

These days, my work – and my life here – seems to revolve around listening. Not just to what’s loud or obvious, but to the subtler signals: the shape of a waveform, the comment a clinician makes in passing, the buzz of ideas across a shared workspace.

The past two weeks have been about steady progress in adjusting circuits, refining ideas, and finding a working rhythm, and somewhere along the way, Nairobi has started to feel familiar. 

Pinard Horn, Rewired

Most of our work recently has centered on our digital Pinard horn, a project that’s grown from concept to code in the past two weeks.

The technical goals sound simple: take the analog sounds from a traditional Pinard horn and convert them into clean, usable heart rate data. But every step along the way has been a learning curve, especially for a team of undergrads not particularly versed in wavelet transform.

We began by studying the frequency ranges of fetal heart sounds. Using a method called power spectral analysis, we learned that the key heartbeats – known as S1 and S2 – typically fall between 46 to 57 Hz, while distracting noise like murmurs or ambient sounds often shows up at higher frequencies. This helped us focus our design on isolating those heartbeat frequencies by creating a band-pass filter that keeps signals roughly between 20 and 200 Hz.

Designing the filter meant making some more choices: do we use FIR filters, which give cleaner alignment of signals but are heavier on memory, or IIR filters, which are more efficient but can shift the signal slightly? After running some simulations in MATLAB and thinking about the kinds of devices this might run on in the future, we are leaning toward IIR. It should give us faster results on constrained microcontrollers – ideal for the environments we’re designing for.

After that, it was time to build. We tuned our amplifier setup and debated what our microcontroller of choice should be – Arduino, ESP32, or Raspberry Pi. We rewired the layout more times than I’d like to admit, but the “aha” moment came when we finally got a clear signal, accompanied by much celebration!

Next step? We want to integrate the signal into our heart rate detection code and clean it up with some digital filtering before we start testing. 

New Project, New Pulse

Alongside our digital Pinard horn, our host-site project at Kenyatta University has officially taken shape – a muscle-preserving active cast designed to reduce atrophy during recovery from limb fractures.

We’ve spent the last few days defining our scope, researching existing tech, and mapping out a development plan. After conversations within the team and with our mentors, we are honing in on electrical stimulation as a viable approach. 

The literature review felt a bit like a treasure hunt, and sometimes a rabbit hole. We filtered through studies on everything from mechanostimulation patches to gel-encased wires that vibrate to keep muscles active

Then we began planning our design: What type of current and pulse duration will be safe? Can we embed electrodes in a cast without conductive gels? What kind of materials will allow flexibility and thermal regulation? We developed a scoring matrix with our design criteria, compared stimulation modalities, and are starting to source some components.

It’s early days, but this project is already pushing me to think across disciplines and approach design challenges with clarity and creativity. 

Between Trees and Time

Over the weekends, we stepped away from the studio and into the trees.

We trekked through Karura Forest, surrounded by fig trees and rustling bamboo. Following a winding trail toward a waterfall, we found caves once used by resistance fighters as refuge.

Later that day, we visited a Maasai village, where we were welcomed with warmth, dancing, and stories. We learned about traditional practices, community structures, and the role of oral knowledge passed from one generation to the next. I was struck by how much care was embedded in everything: from beadwork patterns to the way huts were built using local materials. It was a reminder that good design doesn’t always start in a lab or studio – often, it begins with listening, observing, and understanding daily life up close.

There was something grounding in all of it. In the vastness of the savannah, the calm rhythm of life, and the openness of people willing to share their world with us.

I’ll add photos, but I have to warn you that they barely scratch the surface. 

From Here Onward

Back in Nairobi, we marked the end of the Kenyatta medical device innovation bootcamp with one last dinner – a long table at a Brazilian steakhouse, laughter mixing with the clink of glasses and plates piled high. Everyone was dressed up. Conversation flowed, and somewhere in between passing dessert and hugging goodbye, I realized how much I’ll miss this group.

The Rice360 team will continue at the design studio, working on our long-term projects. Our friends from the bootcamp are going to head back to classes, new jobs, and new cities. I can’t help but think about the friendships we have built here that I hope will last long after this summer! 

Another highlight from last week was getting to meet with our mentors, Michelle and Dr. Lee, who were visiting from Rice. I loved seeing familiar faces, and we were excited to share our project updates with them! We really appreciated them making the time to visit. That evening, we all joined students from different Rice programs across Nairobi for dinner, where we had some delicious Ethiopian food (I’m still thinking about the injera and lentils)! We even met with Rice alumni based in Kenya, and I was reminded of how expansive yet close-knit our community is!

What’s Next

We’re deep into the next stage now. We’re building out the active cast prototype, continuing Pinard horn circuit testing, and preparing documentation and material lists. I’m excited for what’s ahead and to see how our ideas start to take shape!

Signing off before the next leopard sighting (or circuit bug),
Saumya ☀️🐆

Hello again from the City Under the Sun!!

The days in Nairobi start early. They welcome you with warm skies, a clear breeze, and the faint spice of something sizzling in the distance.

There are always greetings and handshakes before my colleagues and I dive into a blur of chisels, wires, and bright yellow tape measures. And somewhere between visiting hospitals and coding projects, something else starts to take shape too: a shared sense of momentum. Of making and unmaking. Of figuring things out together, one busy afternoon at a time!

Building From the Ground Up

We spent our first few days learning to build with our hands at Kenyatta’s Center for Design, Innovation and Engineering. These workshop sessions were all about metalworking – cutting 16-gauge tubing with hacksaws, chiseling stubborn corners, and welding joints by hand. I think I learnt the true meaning of ‘labour of love’ that day! We then moved into woodworking, where we built footstools from scratch. We started with sketches, costed out materials, and began learning different joint techniques. Most of our work was done collaboratively with one member of Team MACAS sanding, another cutting, and another holding things steady.

There were sparks from welding, curls of wood shavings piling at our feet, and quiet wins like clean 45° angles and circuits that finally blinked like they were supposed to. Someone would inevitably start humming along to the jazz during tea break, and there’d be a round of laughter as we debated if something was actually level! 

Listening, Watching, Learning

After getting our hands dirty in the studio, we began the next phase of our work – needs-finding in clinical settings. 

Our first hospital visits were to Thika and Kiambu Level 5 hospitals, where we observed in the maternity, pediatric, and neonatal wards. I watched nurses adapt tools, saw how care is delivered with limited resources, and heard directly from staff about what works and what doesn’t. 

I carried a notebook around everywhere, scribbling down observations, questions, and half-formed ideas. It was clear right away that so much ingenuity already exists within these spaces – small workarounds, creative uses of tools, and thoughtful ways people make do. I remember one nurse explaining how she uses surgical gloves as hangers to accommodate extra IV bags, and another showing us how she warms babies using blankets and layering because the warmer was down again. 

A day later, we visited Kenyatta University Teaching, Referral & Research Hospital (KUTRRH), a Level 6 facility with specialized diagnostic units. In the breast cancer care unit, I observed a mammogram and ultrasound, spoke with staff and patients, and heard stories that were both deeply human and systemic.

There was something powerful about standing in a room full of advanced equipment one day and remembering a borrowed syringe-turned-suction-tool from the day before. The contrast was stark, and it made the big picture even clearer.

This isn’t just about devices. It’s about access, context, and care that fits the place it’s in. It reminded me why I care so much about this work. The people I met were problem-solvers, caregivers, and engineers in their own right. And I want to build things that keep their momentum going! 

When we got back to the design studio, my team gathered around a wide table (still in scrubs and slightly sun-dazed) and started to unpack what we’d seen.

We each grabbed a stack of neon sticky notes and started writing. One note = one observation. The table quickly became a sea of yellows, pinks, blues, and greens. 

“Dogma within diagnostics/procedures”
“No positive flow in O2 cylinder”
“Suction pressure adjusted by guesswork”

Some were messy. Some had drawings. Some had question marks or exclamation points. But they were all tiny windows into systems that were doing their best with what they had.

We stuck them all to the wall, color-coded by theme: equipment gaps, workflow issues, human factors, and improvisation. By the end, the blank wall was covered edge to edge. We stepped back and stared at it for a while. It felt like the beginning of an amazing design process.

Innovation in Every Corner

A few days later, we visited the jua kali sector – Kenya’s vibrant informal manufacturing industry. The name literally means “hot sun,” and it speaks to the intensity, resilience, and creativity of the people working there. As we walked through the maze of open-air stalls and compact workshops, the air filled with the rhythmic pounding of hammers, the hum of metal grinders, and the smell of welding fumes. 

We saw artisans building dishes from scratch, fabricators repurposing scrap into new tools, and sellers customizing devices on the spot for buyers walking by. The engineering skills I witnessed were beyond what you’d expect from any textbook. There was community-driven innovation tucked into every corner of the market.

Later in the day, we also had the chance to step into Nairobi’s innovation ecosystem through visits to Villgro Africa, a startup incubator investing in local health solutions, and Moko, a company turning foam offcuts into upcycled mattresses. I really enjoyed learning about the business side of this field – from funding and product development to scaling and sustainability. It made me think differently, not just about how we build things, but how we get them into the hands of people who need them.

And after one particularly full day of walking around these different industries, we stopped at a quaint roadside cafe where I tried viazi karai: crispy turmeric-battered potatoes served with sweet ukwaju sauce and a cold soda. By now, we were further away from the heart of the city. There was a quiet breeze in the trees and the kind of content silence that comes with a day full of ideas and experiences. 

Ready to Build

And now… we build.

I leave these two weeks feeling inspired, full of ideas, and honestly a little giddy to get started! After all the observing and learning, we’re shifting into the exciting space between problem and possibility. I’ve got sketches in my notebook, ideas in my head, and an amazing team that’s ready to make things happen.

This city – its energy, its creativity, its people – has already taught me so much. And we’re only just getting started. I can’t wait to see what we come up with!

Hadi wakati mwingine,
Saumya ☀️

 

A few weeks ago, I was knee-deep in the OEDK, 3D printing molds, fiddling with adhesives, and sketching prototypes on whiteboards late into the night. Now, I’m writing this from my new apartment in Nairobi, Kenya, where I’ve just started my internship!!

Hi everyone! I’m Saumya Chauhan, a rising junior at Duncan College majoring in Biosciences and minoring in Global Health Technologies. This summer, I’ve packed my bags (and a whole bunch of prototypes) and moved to Nairobi as part of the Rice360 International Internship to work on some amazing global health design projects! I’m incredibly excited to be part of a program that’s all about bridging the gap between innovation and impact, by working directly with the communities and clinicians our designs are meant to serve.

For the next two months, I’ll be working at Kenyatta University’s Centre for Design, Innovation, and Engineering (CDIE), collaborating with students from Kenya and around the world on medical device innovation. We’ll be diving into design workshops, needs-finding in clinical spaces, and collecting real-world feedback on the technologies we’ve helped create. I’m here to learn, ask questions, and build partnerships grounded in context and co-creation.

Alongside working on a new host-site project here in Kenya, I will also be gathering testing feedback on two Rice360 technologies. I will get to see two of our designs in action: Uterus Universal, a training model for endometrial biopsies that I helped develop back in Houston, and a neonatal gastroschisis bag. I’ve spent the past semester troubleshooting technical challenges and imagining how these tools might be used in the field. Now, I get to test them in that very context! I’m excited to see what holds up, what needs to change, and how we can improve based on insights from users.

I’m also eager to learn how to adjust to a new environment: navigating Nairobi traffic (matatus will be an adventure), trying my hand at cooking with local ingredients, and picking up bits of Swahili – so far, I’ve “mastered” jambo (hello), karibu (welcome), and asante sana (thank you very much). I’m excited to improve on technical skills like 3D modeling and woodworking as well.

There’s so much I’m looking forward to! I’m excited to keep exploring Nairobi, to ask more questions, to gain many diverse skills, and to keep building connections that stretch beyond this summer. It’s all still ahead, and I can’t wait to see where it leads!

More updates (and photos!) soon,
Saumya ☀️