The number of parking spaces for people with disabilities is limited. In addition, there is inappropriate use of these spaces. Because of these problems, wheelchair users who really need them are not able to use parking spaces for people with disabilities. Therefore, we developed and tested a device and a smartphone application to monitor the use of parking spaces. An ultrasonic distance sensor was used to detect vehicles. A waterproof ultrasonic distance sensor was used for vehicle detection and a solar battery that can simultaneously supply and charge power was used as the power source. Furthermore, the results of a 30-day operational verification test showed that the system was able to continuously detect the usage status without false vehicle distance detection. However, further improvements are needed as issues were identified that need to be addressed before the system can be implemented in public and commercial facilities.