Introduction: ADITI - Affordable Diagnostic Thermal Incubator
20,000,000 premature babies are born each year and 4,000,000 babies die within their first day of their life. Our solution is a novel diagnostics enabled body warmer which would continuously monitor parameters like Respiration Rate, Heart Rate, Blood Oxygenation (SpO2) and Body Temperature comfortably.
The bodysuit consists of fabric based resistive filaments that safely provide warmth to the neonate as due to preterm birth body is fat is miniscule. The heating is carefully controlled and will use PID control for accurate temperature control. Pulse oximetry would be integrated with the baby's hoodie and would measure the oxygen saturation in blood in the earlobe. Hypoxemia and Apnea can be detected early using Respiration and Blood Oxygenation data to trigger alerts.
The wearable would also provide peace of mind to parents who in many preterm cases. The device can potentially be the only incubation system in remote villages where standard incubators may not present.
Step 1: Problem:
• Preterm birth complications are the leading cause of death among children under 5 years of age, responsible for nearly 1 million deaths in 2013.
• Neonatal incubators are very limited and unavailable in rural areas.
• Preterm birth children are more susceptible to critical conditions like Hypoxia and Apnea
• Risky methods like use of incandescent bulbs are used in rural Primary healthcare centers
• Long term vitals monitoring is really uncomfortable in existing systems and may cause skin irritation to the neonate
Step 2: Existing Systems:
*GE Healthcare - Lullaby baby-warmer
Ease of use & Uniform heat distribution
Con's: Stationary unit & Expensive in comparison to other solutions
Pro's: Inexpensive (25$) & Doesn't require power
Con's: Passive in nature & Cannot detect emergency situations like Hypoxia(Lack of oxygen)
Step 3: Solution:
Our solution is a smart infant bodysuit that consists of fabric based resistive filaments that safely provide warmth to the neonate as due to preterm birth body is fat is miniscule. The heating is carefully controlled and will use PID control for accurate temperature control. Comfortable textile based electrodes monitor ECG, Respiration Rate. Pulse oximetry would be integrated with the baby's hoodie and would measure the oxygen saturation in blood in the earlobe. Hypoxemia and Apnea can be detected early using Respiration and Blood Oxygenation data to trigger alerts.
The wearable would also provide peace of mind to a parents who in many preterm cases are extremely stressed. The device can potentially be the only incubation system in remote villages where standard Neonatal incubators may not be available. The system would be distributed in remote areas through Community Healthcare workers in a rental model and in urban areas it would be post discharge rental system through hospitals.
Step 4: Components:
- MAX30100 - Inexpensive SpO2, HR sensor
- Particle Photon ARM based WiFi dev board
- Eeonyx fabric stretch sensor
- IRFZ544 N-channel MOSFET for PWM heating
- Fabric heating pad LiTex based heating fabric
- LM35 temperature sensor for sensing body temperature
- 4-channel fabric conductive ribbon cable for interfacing MAX30100
- 3-channel fabric conductive ribbon cable for interfacing LM35
Step 5: Respiration Rate Sensing:
Eeonyx fabric respiration sensor :
Use of piezo-resistive fabric sensor to detect expansion and contraction of diaphragm . A Wheatstone network used to measure change in resistance accurately . It is a Low cost and comfortable method compared to Impedance pneumograph.
Step 6: Heart Rate and Blood Oxygenation Sensor:
Photoplethysmography (PPG) and Pulse Oximetry (SpO2) are carried out by a single sensor which is used to measure reflectance of two LEDs of different wavelengths. SpO2 is found by measuring the reflectance of 650 nm light in comparison with 940 nm light. We are currently using the Maxim Semiconductors MAX30100 to reduce the size, cost. The sensor has an integrated amplifier, Analog to Digital Converter (ADC) and inbuilt LED's and LED drives (940nm,650nm). We are working on etextile based system using a 4-channel conductive Textile Ribbon to comfortably transmit the data.
Step 7: Heating Element:
We use the LiTex Stainless steel thread used for warming the child safely and efficiently. We use an IRF544 N-channel MOSFET to warm the child using PWM & PID control (Adjustable securely through OTP login).Ruggedized through the use of Kapton layer, It is ideal for use in this application.
Step 8: Hardware & Communication:
A powerful STM32F205 microcontroller is used for interfacing various sensors. Sleep modes are used frequently to increase the battery life of the wearable. A Broadcom BCM43438 module is used to provide wireless connectivity to the system and supports both Bluetooth Low Energy and WiFi. Even though WiFi is power consuming, we have used it to directly post the data to the cloud over WiFi in the prototype. The WiFi transmission is done in bursts to conserve battery. A chip antenna was used to give a low profile design to the system. Commercially available components were chosen to design ADITI. The future iterations would use a Nordic Semiconductors nRF52832 BLE Micro controller for its extremely low power consumption and low cost. Further due to the presence of NFC in the MCU, Pairing would be extremely simple even for parents without prior education.
The data can either be transferred through the parent’s smartphone if available or through a dedicated gateway device bundled along with the sensor which would send the data to the cloud over Mobile Networks. Even though the availability of mobile network is limited in very remote areas, Initiatives like the Google Project Loon is likely to expand connectivity to even remote locations around the world.
Step 9: Power Management & Battery:
For the prototype we have used a 10000mAh 2A USB powerbank to power the power hogging warmer system. The recent Samsung Galaxy Note 7 explosions brought to light the fundamental flaws in Lion/LiPo chemistries and thus we decide to move away from it in the future.
A 6.4 V, 10000 mAh Lithium Iron Phosphate battery pack is to be used the future revisions of our system. LiFePo4 chemistries are very safe and are unlikely to explode thus making us choose it over LiPo.Due to the lack of electricity in rural areas, We aim to make the battery packs hot swappable with solar charging system for charging the batteries individually.
Step 10: Packaging:
The comfort & safety of the infant was a priority while designing Aditi. We took inspiration from Embrace towards providing Kangaroo care for infants and increase bonding between mother and child. The sensors functional and fabric based to avoid discomfort and we try to be non-obstrusive as possible.
Step 11: Files
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