The Smart Life Guard Pajamas (SLGP) can be useful in two main cases:

1) In the case of Sudden Cardiac Arrest – A lot of adult people suffer from cardiac problems, which can cause Cardiac Arrest. Because of this reason plenty of people die during sleep, without any chance of medical help.
2) In the case of Sudden Infant Death Syndrome (SIDS) – sudden unexpected death of a child in the age until three years.

Depending on the cases the SLGP can be designed in the needed sizes.

It can be designed with two levels of protection:

1) Heart stop alert – it senses the heart pulse rate and when absence of heart beats is registered – it reacts in different ways:
- triggers some sound or light alarm
- sends a message through app to smart phone
- calls some emergency number

2) After registered heart stop, the SLGP makes the alert and starts life recovery procedure – triggers a defibrillator which electrodes are embedded in the SLGP fabric.

To perform these functions the SLGP has embedded in the fabric a heart rate sensor – it can be paced on different positions – but must have constant contact with the skin. To prevent false triggering of the system, this sensor can doubled and working in parallel. An example of such sensor is the Maxim Integrated chip MAX30102. The output of the sensor chip should be connected to some small size microcontroller board. One possible solution is the ESP8266 board – it contains a 32-bit RISC processor and has embedded WLAN transceiver. If there is not any WLAN connection in the proximity different approach can be used. One solution is the use of LoRa transceiver module (SX127x chip) or some portable GSM module.

The SLGP with first level of protection would need only a small LiPo or LiIon battery and charge controller. All these parts are so tiny, so they can be embedded inside the fabric of the pajamas without introducing discomfort.

To be able to work with the second level of protection, the SLGP would require additionally few metal electrodes embedded in the heart area of the pajamas, wired with high voltage insolated cables to a connector, which can be plugged in defibrillator. The defibrillator should be triggered automatically after sending the alert. In this way the life saving procedure can start immediately after the heart stop and the time until the emergency arrives will not be lost.

I hope that implementing the SLGP will allow the relatives of the patients or the parents of the small children to react in time and could save a lot of human lives.