ADITI: Affordable Diagnostic Thermal Incubator

I, Vignesh am a final year engineering student from Chennai, India. I've always been into biomedical sensing and combining electronics and biomedical engineering. Inspired after playing Deus Ex: Human Revolution as a 16 year old, My adolescent my mind was blown away by the possibilities in front of me. Reading about the work done by Dr.Hugh Herr at the Biomechatronics lab and Dr.Rosalind Packard at the Affective Computing lab MIT media lab. I realized I wanted to work on wearable sensors, After seeing the unbelievable progress in Machine Learning for the past few years empowering doctors with Machine Learning for diagnostics is my current goal. Along the way I've read statistics on pneumonia and wanted to do my path, I've also been forming a team to aid us in this. Manoj Kumar is my partner in crime and works on firmware, The "Manoj" heads the design in our team.

While conversing to my friend's father about my earlier work on continuous ECG monitoring who served as Pediatric specialist at Stanley Medical, Chennai. He inquired if I could solve the problem of post discharge continuous monitoring of prematurely born children. He further explained the infant's increased susceptibility to pathogens post discharge and the importance of care. I was shocked to hear that in many primary healthcare centres in rural areas use incandacent bulbs for warming the child resulting in accidental burns. That spurred me to action and I contacted a friend who is a designer to get a few sketches done.

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 centres

• Long term vitals monitoring is really uncomfortable in existing systems and may cause skin irritation to the neonate

Existing Systems:

• GE Healthcare - Lullaby baby-warmer

Pro's:

• Ease of use

• Uniform heat distribution

Con's:

• Stationary unit

• Expensive in comparison to other solutions

• Embrace

Pro's:

• Inexpensive (25$)

• Doesn't require power

Con's:

• Passive in nature

• Cannot detect emergency situations like Hypoxia(Lack of oxygen) Background:

I, Vignesh am a final year engineering student from Chennai, India. I've always been into biomedical sensing and combining electronics and biomedical engineering. Inspired after playing Deus Ex: Human Revolution as a 16 year old, My adolescent my mind was blown away by the possibilities in front of me. Reading about the work done by Dr.Hugh Herr at the Biomechatronics lab and Dr.Rosalind Packard at the Affective Computing lab MIT media lab. I realized I wanted to work on wearable sensors, After seeing the unbelievable progress in Machine Learning for the past few years empowering doctors with Machine Learning for diagnostics is my current goal. Along the way I've read statistics on pneumonia and wanted to do my path, I've also been forming a team to aid us in this. Manoj Kumar is my partner in crime and works on firmware, The "Manoj" heads the design in our team.

Solution: ADITI: Affordable Diagnostics Infused Textile Incubator

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. Our current prototype is designed to fit one of the team mate to first evaluate the sensors and finding & addressing safety issues before working on a miniature version. 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.

Prototype Work:

System Design:

ECG monitoring:

• Single lead ECG with comfortable dry fabric electrodes

• 50hz power line noise removed

• 0.67hz to 55hz bandpass filter

• ADS1292 AFE for ECG processing over SPI

• Data from the MCU is sent to computer over USB for post processing and filtering the ECG signal and for data logging

• Wireless ECG streaming will also be done soon

Respiration Rate Sensing:

Eeonyx fabric respiration sensor

• Use of piezoresistive fabric sensor to detect expansion and contraction of diaphragm

• Wheatstone network to measure change in resistance accurately

• Low cost and comfortable compared to Impedance pneumography

Respiration data plotted

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.

Body Temperature sensor:

The body temperature was also measured nonobtrusively by checking the armpit canal temperature using the TMP36 temperature sensor. It is used to give feedback control for heating element. The analog signal is fed to the MCU’s Analog to Digital converter at 1Hz sampling frequency. We transmit the data over a 3-channel conductive textile.

Heating Element:

We use the LiTex Stainless steel thread used for warming the child safely and efficiently. We use a 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. I aim to evaluate Eeonyx's heating fabric with this along with Peltier thermoelectric modules.

Hardware & Communication:

The powerful Intel quark microcontroller is used for interfacing various sensors and also communicating. Sleep modes are to be used frequently to increase the battery life of the wearable. The Arduino 101 uses a curie chip to send sensory data over energy efficient BLE . Further by adding NFC to 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.

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.

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.

Software:

I'm EE student lacking a lot on software and it's been the main pain point of the project. While I can write some good code for firmware, Cloud and Android dev flies over my head. That being said, I've posted firmware code on Github for the Arduino 101. I'm using Blynk to be mobile and as it's simple. I'll be moving to a custom mobile based app soon and use MQTT to post to a custom secure server in the future. Volunteers for this portions are requested.