The Inspirometer
Incentive spirometers are an inpatient and outpatient prescription with the goal of encouraging deep breathing to inflate bronchioles and alveoli of the lungs. For many pediatric patients prescribed an incentive spirometer, compliance is low because the children do not understand the need or enjoy using the device. Targeted for use by patients 3 to 9 years old, the Inspirometer attaches to the existing incentive spirometer. Through sensors and relay circuits, the Inspirometer motivates children to use the device regularly through positive reinforcement.
How It Works:
A coupled IR phototransistor and LED can detect via the reflection of light whether an object has moved in front of the sensor. When an object is in front of the sensor, the microcontroller and RF transmitter, powered by a battery and rechargable via a charging board, receives a signal to send a "true" signal through the radio to a second microcontroller coupled to an RF receiver. When the "true" signal is received, the microcontroller activates the relay, which allows power to flow to anything plugged into the normally-off switches on the relay. Both the transmitter and receiver components can be turned on and off when not in use
For our minimum viable prototype, we used a bubble machine and a disco ball as the motivating factors that could be activated by the relay. However, these motivating elements can be chosen at the discretion of the hospital. The video below shows the minimum viable prototype with the bubble machine.
My Role:
My responsibilities included assembling the circuit with my teammates and writing the code for both microcontrollers, specifically the code that allows the transmitter microcontroller to receive and interpret an analog signal from the sensor and send a radio signal to the receiver microcontroller and the code that allows the receiver microcontroller to receive and interpret the radio signal, thereby causing the relay to turn on. Because of these responsibilities, I was also heavily involved in troubleshooting our design. The areas I spent the most time on were tuning the IR sensor to be able to work with the microcontroller, increasing the output from the sensor to be readable by the microcontroller, altering thresholds in the code to ensure that the relay would be activated by something moving in front of the sensor, and learning how to communicate encoded messages via radio.
When the design and assembly phase of the project was completed, I was also responsible for three verification tests (dimensional and mass verification, housing drop test, and environmental durability) and two validation tests (operation of spirometer and improved compliance). While the verification tests were completed for inclusion in the DHF for this device, the validation tests were unable to be completed due to the COVID-19 pandemic and were replaced with a survey and video (available at the top of the page).
