Conclusions
The proposed LED image display system can effectively display six patterns by rotating the LED light strips that are mounted on the bike wheel, on account of human visual persistence. A polymer lithium-ion battery supplies power for thirty-six hours to efficiently display the patterns on the wheel of a bicycle. A remote APP design is used to control the patterns displayed on the wheel via a Wi-Fi wireless network. The mobile control and pattern generation programs are designed to select the pattern(s) calculate angle-related information, and transmit control signals to activate LED lighting instantaneously. Experimental results reveal that the system can operate normally when the wheel speed does not exceed 35km/hr. But when the wheel speed exceeds 40km/hr, the patterns are incorrectly displayed during 7% of the rotations. The proposed system is also compared with different LED bicycle wheel light products. All of the previous designs have not provided the ability to change patterns via wireless network. The best bike riding speed of the previous products for displaying the images or words correctly is between 10–30 km/hr. Our proposed design has the lowest price compared with previous designs. It also has better performance with regard to the ratio between working hours and battery capacities, as well as the mobile APP control capacity. To increase the resolution of the patterns in the future, more LED chips will be attached close to each other and a speedy signal transmitting protocol will be developed.