An exploded view of the MEOS Peacemaker patch for the robotics & biomedical team — every layer, its role, the bill of materials, cost ranges, the failure modes we expect, and an eight-week path from schematic to on-body pilot.
The stack is intentionally thin — sensing on top, compute and power in the middle, haptics and housing closing it. Every layer is independently rev-able so we can iterate optics without redoing the radio.
Exploded stack — top of body downward
Ranges reflect ~25-unit prototype pricing from OSH Park (PCB), DigiKey/Mouser (silicon), Protolabs (housing) and a local US contract assembler. At 10k units we expect a 3–4× reduction.
| Part | Vendor | Qty | Cost (USD) |
|---|---|---|---|
| Flex PCB (2L polyimide, ENIG) | OSH Park / PCBWay | 25 | $18.00 – $32.00 |
| nRF5340 SoC | Nordic / DigiKey | 1 | $9.40 – $12.50 |
| MAX30102 PPG | Analog Devices / DigiKey | 1 | $4.80 – $7.20 |
| LSM6DSO IMU | ST / Mouser | 1 | $2.90 – $4.60 |
| DRV2605L haptic driver | TI / DigiKey | 1 | $2.10 – $3.40 |
| LRA coin actuator (10 mm) | NFP Motor / DigiKey | 1 | $3.20 – $6.80 |
| BQ25180 LiPo charger | TI / DigiKey | 1 | $1.60 – $2.40 |
| 55 mAh LiPo cell | PKCell / Adafruit | 1 | $4.50 – $7.00 |
| Qi Rx coil + IC | Würth + TI BQ51013B | 1 | $6.20 – $9.10 |
| TPU overmold housing | Protolabs (SLA + cast) | 1 | $22.00 – $48.00 |
| Silicone gel adhesive disc | 3M / Vancive | 3 | $1.80 – $3.20 |
| Assembly + reflow + test | Local CM (US) | 1 | $35.00 – $70.00 |
| Estimated unit total | $111.50 – $206.20 | ||
HRV signal degrades during walking/typing. Mitigate with IMU-gated adaptive filtering + dual-wavelength.
Edge lift after sweat cycles. Plan two adhesive SKUs (active vs. sleep) and a 72-hour wear study.
55 mAh is tight for BLE + classifier. Budget 4.2 mA avg; consider duty-cycled inference.
LRA feel changes with skin pressure. Calibrate per-user during onboarding (3-buzz tuning).
NTC compensation in firmware; validate from 12 °C to 38 °C skin temp.
Pre-scan at EMC house in week 6 before locking enclosure.
Parallel EE / ME / FW tracks merge at week 5 for bring-up. Week 7 puts ten devices on real bodies for a 72-hour wear study; week 8 is reserved for Rev-B fixes and a demo build.
MEOS Peacemaker is a wearable and app that translates physiological stress signals into gentle, real-time regulation prompts. It is a non-diagnostic prototype designed to support self-awareness and help users notice patterns — not to diagnose or treat any condition.
Most mental health tools arrive after someone already knows they are overwhelmed. But dysregulation often begins earlier in the body: heart rhythm changes, breath shifts, muscles brace, and the nervous system prepares to protect.
MEOS asks a simple research question: Can we detect activation earlier and intervene gently enough to change the next five minutes?
People often recognize dysregulation after the reaction, shutdown, argument, spiral, or avoidance has already happened.
Many apps ask people to self-report emotions they may not yet be able to name.
Meditation and reflection tools are helpful, but often disconnected from the moment activation begins.
MEOS Peacemaker pairs a wearable haptic device with an app-based regulation system. The wearable tracks physiological signals, estimates possible activation, and delivers a subtle buzz when the user may be moving out of their window of regulation.
Something in your body may be bracing.
Want to pause and see what it is protecting?
A narrow, testable, non-diagnostic prototype.
| Component | Purpose | Prototype Notes | Cost Range |
|---|---|---|---|
| PPG Sensor | Captures pulse waveform and HR/HRV-related signals | Controlled-session testing against a reference device | $10–$50 |
| Accelerometer | Detects motion artifact | Separates movement from physiological change | $3–$15 |
| Microcontroller | Runs local sensor and haptic logic | Nordic nRF52/nRF52840 or ESP32-class BLE | $10–$40 |
| BLE Module | Sends data to iPhone app | Must account for iOS background limits | Included / $5–$20 |
| Haptic Motor | Delivers gentle body cue | ERM or LRA vibration motor | $2–$10 |
| Battery | Powers wearable | Rechargeable LiPo for prototype | $5–$25 |
| Enclosure | Holds components comfortably | 3D-printed or soft prototype casing | $20–$150 |
| Adhesive / Band | Keeps wearable attached | Band first, then medical-grade adhesive | $5–$30 |
| iOS App | Displays state, sessions, prompts, logs | Demo + feasibility build | $5k–$30k+ |
| Prototype Assembly | Integrates parts into working device | Engineering, firmware, testing, iteration | $5k–$50k+ |
These are early prototype ranges, not final manufacturing costs. Final cost depends on sensor selection, enclosure design, firmware complexity, and validation requirements.
| Risk | Why it matters | Proposed approach |
|---|---|---|
| Motion artifact | PPG can become noisy during movement | Accelerometer, motion scoring, and signal-quality filtering |
| HRV accuracy | PPG is less precise than ECG | Compare against Polar H10 or research-grade reference in controlled sessions |
| False positives | Too many buzzes could annoy or alarm users | Personalized baseline, cooldown periods, sensitivity controls |
| False negatives | Missed activation may reduce trust | Conservative thresholds and user feedback loop |
| iOS BLE limits | 24/7 connection may not be reliable | Connection windows, local logging, scheduled check-ins, reconnect logic |
| Battery life | Haptics and sensors drain power | Duty cycling, event-based sampling, rechargeable prototype |
| Skin comfort | Adhesive wearables can irritate skin | Test band-based prototype first, then adhesive options |
| Clinical overclaiming | Regulatory and ethical risk | Wellness-first positioning, no diagnosis, no treatment claims |
| Data sensitivity | Physiological and emotional data is personal | Local-first prototype, opt-in data, encryption, delete controls |
Build a working device that reads physiological signals, sends data to app, and triggers haptic feedback.
Test signal quality during rest, stress reflection, breath regulation, and movement.
Recruit a small opt-in adult group. Measure comfort, usability, perceived accuracy, haptic helpfulness, and recovery experience.
Decide whether to continue as wellness wearable, therapist-supported tool, athlete performance product, or clinical research pathway.
The device captures usable physiological data in controlled settings.
Users notice the cue without feeling startled, shamed, or annoyed.
Users report that the cue helped them notice activation earlier.
Users report greater ability to pause, breathe, ground, or choose a response.
The team identifies which signals, thresholds, and prompts are worth studying further.
Early users understand the product and want to keep using it.
We are not asking UW to validate a fantasy. We are bringing a clinically informed problem, a narrow prototype scope, and a testable research question. We want to know whether this can be built safely, measured honestly, and developed into something that helps people notice activation before it becomes behavior.
Support with sensor selection, haptic system, BLE architecture, battery, and enclosure.
Help determine whether the physiological signal is meaningful enough for feasibility testing.
Evaluate comfort, user trust, haptic experience, emotional safety, and usability.
Clarify the path from prototype to wellness product, therapist-supported pilot, or future clinical validation.
The long-term vision is MEOS: a personal emotional operating system that helps people understand their body, patterns, relationships, and protective responses. But the first stone is simple: can a gentle haptic cue help a person notice activation sooner and return to themselves faster?
“The body often speaks before the mind has language. MEOS helps people listen earlier.”