Designing a 4-Channel A/D Application with the PIC12C671. Analog to Digital & Using The 8-Pin PIC: How to build a 4-channel A/D converter using the PIC12C671. This application is excellent for building robotic guidance systems using light to control robotic behavior, serial volt-meters, hobby servo positioning systems, using arrays with PicBasic, you name it...! Lots of possibilities with this project.