The master thesis describes the process of developing a wireless ultrasound spirometer. The first section describes spirometry, measuring methods and the importance of spirometric measurements. Different types of spirometers and their properties are described. An ultrasound spirometer is described more in detail. In the following sections the development of electronics and software of the ultrasound spirometer are described. Within the development of the electronics the process of selecting the integrated circuit and ultrasound transceiver is shown together with the block diagram of the circuit and the printed circuit board. Afterwards the development of device’s software is presented. In software development the operation system and its tasks are defined. In more detail the processes for data acquisition, sending and receiving data over bluetooth and control of the whole system is explained. In the end the testing and evaluation of the device is described. Different tests such as electrical characteristic of the circuit and the accuracy of the measurement are shown. To estimate the accuracy of the final prototype, we compared it to a reference spirometer and verified its compliance with the spirometer standards.
The built spirometer operated in required measurement ranges, operated completely wirelessly and was energy efficient. Compared with the reference spirometer it did not reach the target accuracy specified by the spirometer standards , but it proved to be a robust, reliable and functional prototype device.