An impressive persistence of vision laser projector built using an Arduino and a hard drive case has been demonstrated by a DIY enthusiast. The device uses a circular array of rapidly spinning mirrors to produce horizontal scan lines, with the laser rapidly switching on and off to create line segments that form an image. The device can project one line of text with a maximum of 20 characters and is limited to a distance of about 90 feet.
The designer (Ben), of the device who has shared his experience on his YouTube channel, highlights the importance of laser safety and the use of appropriate safety goggles. He faced a number of challenges in finding the right sensors and redesigning the mirror array. However, despite some issues, the designer is satisfied with how the prototype turned out and is interested in developing the concept further.
The designer also discusses the challenges he faced when experimenting with lasers for the project, and cautions against pointing the laser at any person, animal, or surface. He shares his experience in designing and building the device, including issues with the laser modulation and strange banding effects. To improve the device's portability, he used eight double A batteries and a 3D-printed base section to hold the battery box to the bottom of the hard drive. The designer also added a Bluetooth module for portability and a removable cover for the electronic control board, as well as a 3D printed top cover to protect the rotating components and prevent dangerous reflections of laser light. Overall, the persistence of vision laser projector is an impressive DIY project that showcases the potential of combining hardware and software engineering.