In the past, computer mice were equipped with mechanical balls to measure movement. However, the introduction of optical mice revolutionized the industry by offering improved precision, speed, and the elimination of the need for regular cleaning. Even trackballs, which are known for their wrist-friendly design, now employ optical sensors similar to those found in digital cameras.
Taking advantage of this innovation, Doctor Volt repurposed an old optical mouse into a functional digital camera. While optical mouse sensors and digital camera CMOS sensors both output a 2D array of pixels, there are some key differences. Optical mice rely on frame differences to calculate movement, making them less effective on ultra-smooth surfaces where pixel uniformity makes it difficult to differentiate between frames.
Despite their similarities, optical mouse sensors have lower resolution and color capabilities compared to even budget-friendly digital cameras from the past. Doctor Volt used an older optical mouse sensor with an 18×18 pixel resolution for his project. By deciphering the signal output using an oscilloscope, he generated an array of hex values for each of the 324 pixels per frame. He then used an ESP32 development board to read and display this data on a web interface he had previously created for another project.
Due to the low resolution of the optical mouse sensor, Doctor Volt turned to interpolation to improve the image quality. Using cubic interpolation, he was able to create a higher-resolution image by extrapolating from the low-resolution frames. While this approach worked well for subjects directly beneath the sensor, Doctor Volt wanted to use the device as a functional camera. To achieve this, he 3D-printed a mount for Raspberry Pi-style CS-mount camera lenses. This modification allowed the camera to focus on subjects at a reasonable distance, expanding its range of capabilities.
In conclusion, Doctor Volt’s ingenuity and resourcefulness transformed an ordinary optical mouse into a functional digital camera. Through his modifications and the use of interpolation, he was able to overcome the limitations of the optical mouse sensor and create high-resolution images. This project showcases the potential for repurposing existing technology to serve new purposes and highlights the importance of innovation in the field of electronics.