Firstly about the massage device. We needed to find a solution to create a system which could do a heart massage. After checking at systems such as cylinders, rack and pinion, we have chose to use a crank rod linked with a DC motor and a reduction gear. Our researches on the characteristics gave us each steps of the movement. The massage should be at a rythme of 100 compressions per minute and the piston should give at least 600N on the chest with penetration of 5,5cm. We the help of simulations on SolidWorks Méca3D we have found the characteristics of our motor. We actually have a 400W dc motors 24-48V, 6 000RPM-12 000RPM, with a reduction gear of 1:100. Here our motor would turn under 40V for a rotation speed of 1000RPM and a couple of 29,5Nm and a rotation speed of 100rpm at the exit of the reduction gear. We designed the whole system with different materials to limit friction and manufactured it in our school.
The insufflator system has been design to be able to insufflate de perfect amount of oxygen in the victim's lungs. We chose to compress a special medical balloon used in hospitals with a press and a rack and pinion. This device is connected to the massage with a special rythme directed by the microcontrolor. Actually the whole system should respect this special pace of 30 compressions-2 insufflations. To manufacture the rack you used laser cutting.
In terms of electronics we took the decision of designing our own card and manufacturing it in China , by JLCPCB, to limit use of wires everywhere. Our microcontrolor is a ESP32, it includes many functions such as: possibility of communication with rescue, communicate with a screen to explain users where to place SierrOs on the victim, drawing a Electro-cardiodiagram with electrodes, measurements of the quantity of oxygen in blood...
SierrOs is power supplied with 3 batteries LiPo which give us an autonomy of an hour.