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.
Then came the Masai Mara. My family had flown into town to celebrate my sister’s 18th birthday. We woke before sunrise and climbed into our safari van with flasks of tea and blankets draped over our shoulders. Each morning started with a spirited Twende from our guide Kasaine, and as the sky turned from lavender to gold, the Mara came alive around us. Elephants moved through the morning mist, their silhouettes large and silent. Zebras grazed in loose formation, and Cheetahs rested under acacia trees, eyes half-closed in the sun. We watched a pride of lions stretch and yawn, the cubs tumbling over one another while the older ones looked on. And in the distance, giraffes glided across the savannah, impossibly tall and graceful.
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 ☀️🐆