An early prototype of a mobile device that can sense breathing rates using an infrared LED sensor and IR photosensor to measure the oxygen in the blood is presented.

Breathing rate sensors have been used as medical devices for many years, and wireless versions could be useful for monitoring patients at home or on the move. This manuscript describes a low-cost sensor system designed to measure these vital signs directly from the patient’s wrist. The system uses two light sources: one emits near-infrared radiation (940 nm) and scatters off tissue to detect blood volume, while another is modulated at 40 kHz and measures respiration by detecting chest movement with a photodetector placed close to the skin surface. By measuring pulsatile changes in blood volume, this system can be used to derive the breathing rate.

The respiration sensor is implemented with infrared LED modulated at 40 kHz and a photodetector placed 20 mm away. The photodetector outputs are simultaneously sampled by a microcontroller, through which digital control signals are generated to enable serial communication via UART. These values are then wirelessly transmitted in real-time using Bluetooth Low Energy (BLE) technology. This approach allows multiple transmitters to operate simultaneously within close range of one another while using minimal power due to the low duty cycle associated with each transmitter module. To demonstrate this concept, two breathing sensors were built out of 3D printed components on flexible PCBs for placement around the wrist or chest.

The sensing platform is connected to a smartphone that provides software services for data logging, transmission, and visualization. It has been shown above to provide accurate data with minimal hardware costs, while the modular design could be integrated into multiple wearable devices.

Some of the best mobile breathing rate sensor companies are:

1. LumaSense Technologies, Inc: This company provides a wide range of products that include infrared gas sensing technology, portable, low-cost sensors for monitoring indoor/outdoor air quality and CO2 levels, PointSense handheld sensors for measuring gas plumes. LumaSense manufactures cost-effective devices that are widely used by many industries in diverse applications such as power generation, environmental protection, firefighting, and homeland security. LumaSense has an extensive clientele that includes Fortune 500 companies, government agencies, educational institutions, and local terrorist-response teams.
2. G-TEK USA, LLC: Founded in 2001, Gtek enterprise is focused on designing and manufacturing custom Portable Gas Detection Systems for any application. The company aims at providing high-quality products (mobile breathing rate sensor) to its clients at the most competitive prices while maintaining excellent customer service. Gtek specializes in gas detection systems for energy & industry; chemical processing; commercial buildings; marine applications; homeland security; oil & gas; mining & tunneling; military/aviation; hazardous material incident (HAZMAT) response teams etc.
3. TST Industrial Products: TST Industrial is a leading manufacturer and distributor of industrial safety equipment. We specialize in breathing safety devices, gas detectors, personal protective equipment, ventilation fans, and control valves, among other things. Our high-quality products are customizable to the needs of our clients from various industries, including petrochemical, manufacturing, electric power generation, and mining.
4. Air Sensor Technology Ltd: A company that manufactures a wide range of sensors for many applications such as particle counters, carbon dioxide analyzers & breathalyzers. The BreathometerCO2 is a new type of highly accurate CO2 sensor suitable for monitoring patient respiration rates or real-time CO2 concentration within confined spaces where instant measurements are required – all via a smartphone!
5. Shalon Medical Corporation: Shalon Medical is a global leader in the design and manufacture of reliable, affordable, and easy-to-use medical devices for respiratory care. They offer products and services that allow children and adults with disabilities to experience an improved quality of life by expanding their communication, socialization, and independence.
6. Personal Chemistry: Provides oxygen monitors for indoor air quality that measure the oxygen level (air), water vapor (humidity) & temperature. The compact size makes them ideal for use at home or office – anywhere where safe breathing conditions are critical. The O2 monitor can also be configured to be used as a CO2 monitor (carbon dioxide).