A friend of mine asked me to design a home automation for him. He wants me to build something that will communicate with his air condition through an IR receiver that it has, and it will act as a programmable timer, to turn it on and off automatically. This circuit will help you understand how to use the built-in I2C communication module of PIC microcontrollers, and also how to use the Maxim DS1307 Real Time Clock chip.
Using a potentiometer, i control the speed of a PC fan, from 350rpm up to it's max speed (1300 rpm). The fan is a 3-wire PC fan. Using the Pulse-Stretching method, i get accurate RPM feedback, twice a second, and display them on an LCD display.
From time to time, i have use many circuits that generates PWM pulses. Most of them will translate a resistor value into duty cycle change. Although that is handy and easy, sometimes a voltage controlled PWM generator is needed. There are of course those micro-controllers that could make almost any kind of PWM signal translation, but i preferred to study and create a circuit without the use of such chips. I tried to keep it as easy as can be, but without this reflecting to the accuracy and integrity of the output pulses.
I just got a 100 Watts submersible aquarium heater from ebay! No, i don't have a fish aquarium in my house, nor any other living creature larger than bacteria or other microorganisms. The reason that i bid on this item is because i will use it for my homemade PCB etch bath!
Hello to pcbheaven's readers once more!!!!!In the following pages i will present you an RFID reader connected to a pic microcontroller.The pic microcontroller is the pic16LF1939 from microchip and the Rfid reader is the MiniProx 5365 from HID global Secure Identity Solutions.Their datasheets are able to be downloaded from here and here.
The pic runs at 16mhz internal clock speed and the oscillation frequency of the Rfid reader is at 125mhz.The communication between the pic and the reader is accomplished through the wiegand protocol.I will provide extra info of how this protocol works on the reference section.
