The challenge
Ship strong security and real breathing intelligence, on the same
timeline
Somnox builds connected sleep companions that guide people into rest.
The range spans two devices, the full-size Somnox Pro for the bed and the handheld Somnox Go for on the go.
Neither problem could be allowed to delay the other:
- A regulatory deadline. Under the EU Cyber Resilience Act, from
2027 connected devices placed on the European market must implement end-to-end
security. Secure boot and a secure update path had to be designed, built,
and documented, without pushing back the firmware schedule
- Security beyond the firmware. End-to-end means the device, the
mobile app, the cloud backend, and the manufacturing process all had to
hold the same guarantees, with documentation able to satisfy a CRA consultant's
review
- Secure manufacturing at scale. Provisioning cryptographic identity
on a factory floor leaves little room for error and is a common target
for attackers, Somnox needed a flashing process that was secure, cloud-integrated,
and itself CRA-compliant
- Every sleeper breathes differently. Detecting breathing reliably
enough to respond to it, all night, on-device, from motion alone, is
a genuinely hard signal problem. And it had to work across two very different
products
- No real data to learn from yet. Improving the algorithm needed
real-world sensor data from real sleepers, captured in a form ready for
post-processing and analysis. That pipeline did not exist
The work
Five domains, one team
As Somnox's embedded engineering partner, c4micro owned the firmware
stack end to end and worked closely with Somnox's team and their
partners. Each problem maps to a deliberate engineering decision.
- End-to-end security, delivered on schedule, a complete secure
boot and secure firmware-update architecture, engineered in parallel with
feature work. Device trust is rooted in hardware: eFuses burn a unique
AES-256 flash-encryption key, HMAC key, and RSA-3072 Secure Boot digests
into every unit, then permanently disable all debug interfaces
- Security across the whole chain, direct collaboration with Somnox's
app developer, backend developer, and CRA consultant to make the guarantees
hold from cloud to phone to device, backed by a maintained threat analysis
and traceable mitigations
- A secure, cloud-integrated factory flasher, pulls each device's
unique key material from the cloud at flash time, uses it only in volatile
memory, and wipes it the moment provisioning completes. The cloud can
disable any flasher station at any time, cutting off its ability to provision
further devices
- Breathing detection from motion alone, algorithm development with
Somnox's team to detect a sleeper's breathing from IMU readings, with
field logging infrastructure that streams real-world sensor data back
for post-processing and continuous improvement
- Breathing guidance that meets you, then leads you, the device
first synchronises to the user's own breathing rate, then gently slows
that rhythm toward the deep, slow rate associated with relaxation and
sleep onset. Field-deployed and trusted by users today
ESP32-S3 · FreeRTOS · C++23 · BLE
5.0 / NimBLE · RSA-3072 Secure Boot · AES-256
· Dual-slot OTA · EU CRA ·
Cloud-integrated factory flasher
