Experiments with PIC16F628A

Besides just turning ON and OFF, there are lot of other stuff that you can do with LEDs. In one of my experiments, I showed how to control the intensity of an LED using PWM. Here's a project that uses the similar concept to generate 8-channel PWM signals through PIC16F628A ports and drive 8 LEDs with 4 levels of intensity. A number of visual effects and chase sequences are programmed into the firmware. Enjoy watching this video! 

This is an extension of Experiment No. 8 ( Click Here ). The PWM output is here connected to power a DC motor through a NPN driving transistor. The motor driving circuit is built in a breadboard, as shown below. The circuit is pretty straight forward, the PWM output from PIC pin drives the BC547 transistor ON and OFF, and the current to drive the motor is provided by the collector current in the transistor. The diode is for back EMF protection. I am using a small 6V DC motor from an old cassette player. For motors that require more current to drive, a darlington transistor pair or high power transistor is recommended.