This circuit is a MIDI interface between drum pads and computer or hardware sequencer. Using this circuit you can hit pads with drumsticks and store the MIDI data in real time.This circuit is based around the PIC16C84 microcontroller which scans the inputs on RB0 to RB7 and when a high is detected the software transmits the equivalent note-on ( and then the MIDI note-off after a short delay) for the required drum sound on the MIDI output on RA0. source

The stepper motor will turn the ultrasonic range finder in 360 degrees and reverse (Cool, isn’t it?). When two measurements have been made, the PIC will send out the data to the PC by using an asynchronous interrupt transfer. The timer in the PIC controls the stepping motor turning speed.source

This project has quite a few robotics applications as well.could build a robot with 8 servo motors and control him directly from the Servo Commander software interface, or use the PIC16F84 as the dedicated servo control chip in your Basic Stamp projects. Once you have experimented with the Servo Commander software and the PIC servo controller you will probably come up with hundreds of other applications.source

The program uses two pulsewidth variables, pw1 and pw2; and two sets of routines, left1 and left2, right1 and right2; one for each motor. As you can see in the schematic, the first servo is wired as per the previous circuit. The second servo is now using B3 as it’s pulse out, and B4 and B5 for the SPDT switch.source

PIC controller based heater controller. It’s based around a pump controlled boiler/radiator system. A PIC16F84 is used to input the set point and control a pump to circulate the heated water as needed. source