Would you know what to do if you had someone's life in your hands? And if your life were in the hands of someone else, what would you like to him know? I am Mariana, I study Mechatronics Engineering and I am scout, this important part of my life that taught me to always be prepared to help others. 50% of lives can be saved with the proper use of First Aid, but only 1 in 100 Mexicans know how to do it. Respiratory cardiac arrest is the abrupt and unexpected interruption of breathing and circulation, potentially reversible. This can be by cardiopulmonary resuscitation maneuvers, often of 100 over 60 seconds, in 5 cycles of 30 beats and 2 insulfations. There is a large number of courses that train you, of around 1000 pesos, in which you have 30 companions and 1 or 2 paramedics, which you can’t be entirely with you, checking your progress. And a simple mannequin is not enough. How can you know if the frequency and the pressure is the correct one? RetroCP is an adaptable system that instantly feeds the performance of your maneuver and counts the cycles, in this way you can adequate your performance, this practical product will let you know if you are doing it right, or not and your patient is dead, then it will restart. While other feedback systems cost more than $ 5000, the cost of RetroCP is only the ten percent of this. Learning is helping, we can all save lives, we can all be save. Born like a Scout project, grown like a scolar project and saw the light in the "Concurso Nacional de Prototipaje" where it won the second place.