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Zephyr-Based Handheld Multi-Parameter Veterinary Vital Signs Monitor

Handheld battery-powered veterinary vital-sign monitor with SpO2, ECG, temperature, CO2, blood pressure, wireless connectivity, and a touch display running Zephyr.

Advanced Project — This is advanced because it combines medical-style biopotential sensing, optical SpO2, NDIR CO2, a cuff-based blood-pressure subsystem, WiFi/BLE, battery power management, and production-level EMC and safety concerns in one handheld device.
Assumptions:
  • Blood pressure is intended as a cuff-based noninvasive NIBP subsystem, which is not covered by the provided database parts and will need separate pump/valve/pressure-sensor hardware.
  • The ECG is single-lead or limited-lead monitoring rather than a full diagnostic 12-lead system.
  • The color LCD with capacitive touch is a custom production display module, not a dev kit.
  • Zephyr will run on the main application processor, with wireless and UI handled on the same MCU.
  • 8-hour runtime assumes duty-cycled sensors, display dimming, and aggressive low-power firmware; continuous CO2 and display backlight at full brightness will reduce runtime significantly.

Bill of Materials

Microcontroller
Top Pick ESP32-WROOM-32E-N4 Espressif Systems From our database
ESP32-WROOM-32E-N4 is the best overall pick because it gives you WiFi, Bluetooth LE, and enough CPU for Zephyr-based UI and sensor orchestration in a single production module.
Mouser $5.59 (58,004 in stock) Digikey
ESP32-WROVER-E-N4R8 Espressif Systems From our database
Adds extra RAM over the base ESP32-WROOM-32E-N4, which helps with graphics, touch UI, wireless stacks, and buffering sensor data. Good choice if the display stack or logging becomes memory-hungry.
ATSAMD21G18A Microchip Technology From our database
Low-power MCU with good peripheral set, but it lacks integrated WiFi/BLE and is a poor fit for this connected product unless paired with a separate radio. Included only as a lower-complexity fallback.
ECG Front End
Top Pick MAX30003 Maxim Integrated (Analog Devices) From our database
MAX30003 is the best fit because it is specifically designed for ECG acquisition and gives you a cleaner production path than the simpler an alternative part.
Mouser $15.25 (1,850 in stock)
ADS1298 Texas Instruments From our database
Highly integrated multi-channel biopotential AFE with simultaneous sampling and 24-bit conversion. Strong choice if you want more than one ECG lead or future expansion, but it is more complex and power-hungry than a single-channel solution.
SpO2 Sensor
Top Pick MAX30102EFD+T Analog Devices Inc./Maxim Integrated From our database
MAX30102EFD+T is the best practical choice because it combines the optical elements and digital interface needed for SpO2 in a compact, production-friendly part.
Mouser $16.44 (405 in stock) Digikey
MAX30105 Analog Devices AI suggestion - verify availability
Related optical sensor family with similar integration and easy digital interfacing, but it is more often used for general optical sensing than dedicated SpO2. Only a fallback if you need a different package or sourcing option.
AFE4404 Texas Instruments
Dedicated optical AFE for pulse oximetry with more flexibility for custom LED/photodiode arrangements. Better for a higher-end design, but it requires more external optics and analog design effort.
Mouser $6.18 (371 in stock)
Temperature Sensor
Top Pick MCP9808 Microchip From our database
MCP9808 is the best fit if temperature accuracy matters for a veterinary monitor, while TMP112AIDRLR is the lower-power alternative.
Mouser $1.40 (3,112 in stock)
TMP112AIDRLR Texas Instruments From our database
Low-power, accurate digital temperature sensor with I2C interface and small footprint. Good for board or ambient temperature monitoring in a battery-powered handheld device.
TMP117 Texas Instruments
Very high-accuracy digital temperature sensor with excellent low-power behavior. A strong production option if you want tighter temperature accuracy than TMP112, but it is not in the provided database.
CO2 Sensor
Top Pick SCD30 Sensirion From our database
SCD30 is the best verified production-grade option in the provided database because it uses true NDIR CO2 sensing, which is appropriate for a clinical monitor.
Mouser $36.02 (1,812 in stock) Digikey
SCD41 Sensirion From our database
Smaller, lower-power NDIR CO2 sensor family member that is often better suited to handheld battery products. Strong option if you need to preserve runtime and board space.
SCD4x CO2 Gadget Sensirion From our database
Useful for evaluation and prototyping of the SCD4x family, but it is not a production sensor. Included only as a development reference, not a final product part.
Blood Pressure Subsystem
Top Pick MPRLS0025PA00001A Honeywell From our database
MPRLS0025PA00001A is the best starting point for the blood-pressure sensing element, but note that a complete cuff-based BP subsystem still needs pump, valve, tubing, and control firmware.
Mouser $18.47 (3,766 in stock) Digikey
NPA-700B-001D Amphenol Advanced Sensors
Compact pressure sensor option for cuff pressure measurement with a digital output family that is commonly used in medical and industrial designs. Good if you want a small, modern pressure sensing element.
MPXV7002DP NXP Semiconductors From our database
Differential pressure sensor family often used in airflow and pressure applications. It can work in a cuff system, but the overall NIBP subsystem still requires substantial analog and pneumatic design.
Power Supply
Top Pick BQ24040 Texas Instruments From our database
Top pick: BQ24040 (Texas Instruments). Simpler single-cell Li-Ion charger with power-path support for compact portable products. Easier to integrate than a full charger/PMIC, though less feature-rich than BQ25895RTWR.
Display
Top Pick DT028BTFT-PTS2 Displaytech From our database
DT028BTFT-PTS2 is the best overall display choice because it already includes capacitive touch and offers a practical handheld form factor.
Mouser $40.88 (183 in stock)
DT035BTFT Displaytech From our database
3.5-inch color TFT with 320x240 resolution, giving more room for waveforms and numeric vitals. Better if ECG and trend data need to be visible at once, but it is larger and likely higher power.
WF18GTZAADNN0 Winstar Display From our database
Small 1.8-inch TFT with SPI interface and low complexity, but it is too small for a multi-parameter veterinary monitor UI. Included only as a compact fallback.

Compatibility Notes

  • ESP32-WROOM-32E-N4 uses 3.3 V logic, which matches the I2C sensors and most modern display interfaces, but the display module and any analog front-end support circuitry must be checked for exact I/O voltage requirements.
  • MAX30003, MAX30102EFD+T, TMP112AIDRLR, and the recommended pressure sensor concept all use digital interfaces that are straightforward to connect to the ESP32, but the ECG and SpO2 analog/optical front ends need careful PCB layout and low-noise power rails.
  • ESP32-WROOM-32E-N4 is for a single-cell Li-ion battery, so the battery pack, charger thermal design, and runtime budget must be sized around one-cell operation unless you redesign the power tree.
  • SCD30 is relatively power-hungry compared with the other sensors, so continuous CO2 measurement will be one of the biggest threats to the 8-hour battery target.
  • The blood-pressure subsystem is incomplete with the sensor alone; it also needs a pump, solenoid valve, pressure tubing, and a control algorithm, none of which are covered by the provided database parts.

You'll Also Need

  • Cuff pump, exhaust valve, check valve, tubing, and cuff hardware for blood pressure.
  • Medical-grade isolation, patient protection circuitry, and compliance work for ECG/SpO2 safety.
  • Battery cell, protection circuit, pack connector, and mechanical battery holder.
  • Display backlight driver, touch controller if the chosen display does not include one, and any required level shifting.
  • Analog front-end support passives, anti-alias filters, ESD protection, and precision resistors/capacitors.
  • Enclosure, gasket/sealing, connectors, flex cables, and PCB assembly materials.
  • Calibration fixtures and production test software for ECG, SpO2, CO2, and NIBP validation.
Estimated BOM Cost: $180-200 (based on live distributor pricing)

Design Considerations

Battery Life
An 8-hour runtime is feasible only if the display backlight is dimmed aggressively and the CO2 sensor is not run at maximum duty cycle all the time. The ESP32-WROOM-32E-N4 can sleep well, but the display, SCD30, and optical sensors will dominate average current. Budget the system around a few hundred mA peak and aim for a much lower average by sampling ESP32-WROOM-32E-N4 in bursts and updating the UI at a modest rate.
ECG and SpO2 Signal Integrity
The MAX30003 and MAX30102EFD+T should be placed with short, quiet traces and a solid analog ground strategy to keep motion artifact and switching noise out of the measurements. Keep the WiFi antenna area physically away from the biopotential front end, because RF bursts from the ESP32 can corrupt low-level analog signals. In production, you will want a repeatable electrode/contact and optical-mechanical design more than just a good schematic.
Blood Pressure Subsystem
A cuff-based NIBP design is a full subsystem, not just a sensor, and it is usually one of the hardest parts of a handheld monitor. You need pump control, valve timing, pressure calibration, leak detection, and a robust inflation/deflation algorithm to avoid false readings. Plan for extensive bench testing with known pressure references and multiple cuff sizes before any field use.
Firmware Architecture
Use a state-machine architecture with separate tasks for acquisition, UI, wireless telemetry, battery management, and fault handling. Zephyr is a good fit, but you should still add watchdog recovery, sensor health checks, and graceful degradation if CO2 or BP hardware fails. OTA update support is strongly recommended for production because medical-style devices often need post-deployment fixes.
EMI, ESD, and Layout
This product combines WiFi, BLE, high-gain analog sensing, and a touch display, so PCB partitioning matters a lot. Put the ESP32 antenna at the board edge, isolate the ESP32-WROOM-32E-N4 analog sections from switching regulators, and add ESD protection on any patient-facing or external connectors. Poor layout will show up as noisy waveforms long before it shows up as a software bug.
Production Validation
You will need separate validation plans for each measurement modality: ECG waveform fidelity, SpO2 accuracy across perfusion levels, CO2 response time, temperature accuracy, and BP repeatability. Test battery runtime with worst-case display brightness and wireless activity, not just idle current. For a production device, build in self-test modes and sensor fault detection so the unit can flag bad electrodes, blocked airflow, or low battery before it gives misleading readings.

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