A device for measuring respiratory rate has been purchased for Lisa

Meet Elizabeth. Despite her serious illness - Spinal muscular atrophy, Lisa is a very active girl. He likes to draw and play with the guys. Moreover, she "runs" in her wheelchair sometimes faster than her friends. She is open, friendly and very cheerful. Due to her rare disease, she needs to measure her respiratory rate. For this purpose, there are special portable devices for home use. They are very expensive for a small family of two people. Let's help Lisa buy a device for measuring respiratory rate together