Tilt sensor for SIDS prevention in baby mattresses

Abstract

Baby mattress with a sensor unit integrated into the mattress structure, characterized in that the sensor unit includes a motion sensor designed to detect the upper body inclination of an infant.

Description

Technical background and problem statement

[0001] Sudden Infant Death Syndrome (SIDS) is one of the leading causes of unexpected death in infants worldwide. Studies show that in approximately 80% of documented cases, the cause is an unnoticed rolling onto the stomach – a position that can impair breathing.

[0002] Deficiencies of existing systems: • Surveillance cameras: Expensive, internet-dependent, violate privacy. • Wearables: Uncomfortable, potential choking hazard due to small parts. The innovative solution

[0003] The innovative solution consists of a contactless tilt sensor that is invisibly embedded in the mattress.

[0004] The sensor detects dangerous body positions (e.g., lying on the stomach ≥ 90°) and triggers a Bluetooth Low Energy (BLE) alarm to the parents' smartphone within 3 seconds - completely without camera, microphone or body contact. Brief description in layman's terms • The sensor continuously measures the baby's upper body tilt. • A wireless alarm is triggered when a critical angle is reached (≥ 90° ± 5° for at least 3 seconds). • The system works completely passively, without contact and without disturbing sleep comfort. • The box is childproof, with no openings or loose small parts. Special features: • Reaction time: ≤ 3 seconds • Accuracy: ± 5° • Energy-saving thanks to BLE 5.1 • Made from ≥ 90% recyclable material • Easy to install, removable without residue Technical setup of the electronic unit (sensor box) • Shape: Closed, square plastic box • Dimensions: approx. 6.5 × 4.0 × 1.5 cm - flat, unobtrusive design to avoid any pressure stress • Installation depth within the mattress: The sensor box is positioned at a depth of approximately 1.0 to 1.5 cm below the mattress surface in the area of ​​the shoulder blade. • Material: Impact-resistant ABS plastic • Construction: The box is completely sealed and has no external openings or removable parts. Electronics (internal) • Sensor: MPU-6050 (3-axis gyroscope), fixed at a tilt angle of 15° • Processor: nRF52840 with Bluetooth 5.1 (BLE) • Battery: Li-Po 3.7 V / 300 mAh (Expected operating time under typical conditions: up to 30 days, depending on usage and environment) Integration in the final product (baby mattress) • The sensor box is not intended as a separate product, but is fully integrated into a specially designed baby mattress. • The placement takes place in the area between the baby's shoulder blades, within the mattress structure. • Firmly embedded at a depth of approximately 1.0 to 1.5 cm below the mattress surface, additionally protected by a 2-3 mm thick silicone layer. • The box has no direct contact with the baby's body and remains imperceptible to the child. • This installation method ensures safe, comfortable and contactless operation without compromising sleeping comfort. Measurement principle

[0005] The slope θ is calculated as follows: θ=arctan(√(x2+y2) / z) • Data acquisition: every 100 ms • Digital low-pass filter: 5 Hz • If θ ≥ 90° for ≥ 3 seconds → Alarm • Event logging: up to 100 events in case of connection interruption Flowchart 1. System startup and calibration (10 s) 2. X / Y / Z data acquisition every 100 ms 3. Data filtering (5 Hz) 4. Calculation of 8 and Δθ / Δt 5. Decision: θ ≥ 90° for ≥ 3 seconds? 6. Yes → Send alarm via BLE 7. No → Return to measurement 8. If no connection exists → Data is temporarily stored Technical distinction from known solutions (state of the art)

[0006] The present invention differs significantly from existing monitoring solutions for infant sleep. While known systems often rely on complex and costly technologies, the invention pursues a minimalist yet highly effective approach to risk prevention.

[0007] Compared to previous solutions, the invention is characterized by the following technical differences: • No camera system required: Unlike video-based solutions, this system operates entirely without visual monitoring. This avoids data privacy issues and reduces production costs. • No acoustic signals or noise detection: No microphones or noise sensors are used, which reduces complexity and eliminates potential false alarms caused by ambient noise. • No direct body contact required: Unlike wearable devices (e.g., wearables or sensor wristbands), the system works without contact and is fully integrated into the sleeping surface. This increases comfort and minimizes the risk of swallowing small parts. • No mechanical movement units: The solution does without vibrating or active movement components. Instead, risk assessment is based solely on the continuous evaluation of the body's tilt angle. • Energy efficient thanks to BLE 5.1: The system uses modern Bluetooth Low Energy technology (BLE 5.1) and is therefore designed for long-term battery operation (≥ 30 days) without constant charging. • Independent of Wi-Fi / Internet: The device works locally and does not require an internet connection, which increases both privacy and system security.

[0008] This combination makes the invention significantly more advantageous than known approaches in terms of security, data protection and cost structure. Safety aspects and legal information o Maximum temperature development

[0009] The electronic unit is designed so that the temperature development does not exceed 1 °C above the baby's body temperature in order to avoid thermal stress during sleep. ◇ Legal Notice

[0010] For legal protection, the following notice is included on the packaging or in the documentation: "This product is not an approved medical device as defined by the MDR or FDA." ◇ Signal filtering

[0011] To reduce false alarms caused by minimal vibrations or non-critical movements, a digital low-pass filter with a frequency of 5 Hz is used. This enables reliable tilt detection while maintaining high interference immunity. ◇ Silicone protective layer

[0012] It is recommended to integrate a 2-3 mm thick layer of silicone between the surface of the casing and the mattress cover. This provides additional thermal and mechanical protection as well as increased sleeping comfort. ◇ Battery specification

[0013] A 3.7V / 300mAh Li-Po battery is used, offering a lifespan of approximately 300 charge cycles. Under normal operating conditions, this equates to well over a year of use without any noticeable loss of performance. Why this invention is worthy of protection • Solves a socially relevant problem (SIDS) • Technically simple, but highly effective • Low costs with high security • Contactless, energy-efficient, privacy-friendly • Ideal for broad markets (families, clinics, midwives) Reference symbol list: Fig. 1: Baby mattress with integrated sensor box 1 baby mattress 2 Sensor boxes 3 2-3 mm thick silicone layer 4 1.0 - 1.5 cm depth Fig. 2: Sensor box with internal components 5 Sensor MPU-6050 6 Processor: nRF52840 with Bluetooth 5.1 (BLE) 7 Battery: Li-Po 3.7V / 300mAh Fig. 3: Tilt detection - Normal position (15°) 8 Secure basic position (15°) Fig. 4: Tilt detection - danger position (≥ 90°) 9 Danger position (alarm trigger) (≥ 90°) Fig. 5: Data flow diagram 10 MPU-6050 Sensor 11 Signal processing unit 12 Decision logic θ ≥ 90° ± 5° for ≥ 3s ? 13 BLE alarm module 14 measurement repeats 15 Event log Fig. 6: Circuit diagram 16 USB charger 17 Li-Po battery 18 MPU-6050 Sensor 19 programming ports 20 nRF52840 processor 21 BLE module 22 Smartphone

Claims

[1] Baby mattress with a sensor unit integrated into the mattress structure, characterized by that the sensor unit includes a motion sensor designed to detect the upper body inclination of an infant. [2] Baby mattress according to claim 1, characterized by that the motion sensor is arranged at a fixed tilt angle of 15° inside a closed, childproof plastic box. [3] Baby mattress according to any of the preceding claims, characterized by that the sensor unit automatically sends an alarm message via Bluetooth Low Energy (BLE) to a mobile device when the upper body is tilted at least 90° for a duration of at least three seconds. [4] Baby mattress according to any of the preceding claims, characterized by that the plastic box is completely sealed, has no external openings and is additionally protected by a 2-3 mm thick layer of silicone. [5] Baby mattress according to any of the preceding claims, characterized by that the construction consists of at least 90% recyclable material and contains no small parts that could be swallowed. [6] Baby mattress according to any of the preceding claims, characterized by that the electronic unit is designed so that its temperature does not exceed the infant's body temperature by more than 1 °C. [7] Baby mattress according to any of the preceding claims, characterized by , that the data processing includes a digital low-pass filter with 5 Hz to avoid false alarms caused by minimal vibrations or non-critical movements.

Images