The Digital thermometer was built by using the temperature sensor LM35DZ, PIC16F877 microcontroller and MAX232 IC. Temperature measurements can also be viewed on a computer program which can monitor the state of COM ports of a PC. Sample measurement data received through COM2 is being viewed on the SERIAL WATCHER program which is distributed freely on the internet.
Digital thermometer: [Link]
The circuit here described is a simple 4×5 keypad that can be used in particular with the PIC 16F877 microcontroller, for which it has been designed considering a supply of 5V, 16F877 I/O pins leakage current, the voltage level recognized as a high or low state while in TTL or ST mode, etc.. Since this circuit is quite simple, and the resistors’ value not critical, it should be suitable for other PICs and other microcontrollers, too.
PIC16F877 and 4×5 keypad: [Link]
This circuit is not a PIC programmer, but it can be easily interfaced with one of the many programmers you can find, allowing you not to remove the microcontroller from the board (in-system programming).
Compared to the version 1.1, connection also to LVP programmers is now supported; besides this characteristic, it is of course possible to work both with chips with the LVP bit set (just a switch need to be set) and with the LVP bit not set; it is of course possible to interface the board with traditional programmers (12 V on /MCLR), the most part, I would say.
PIC 16F877 / 16F874 Development Board: [Link]
The EnerJar is an easy-to-build device that accurately measures the power draw of electrical appliances. The EnerJar was the winner of the Greener Gadgets design competition. The design is still being optimized, but preliminary schematics and source code can be found by following the link bellow.
The EnerJar: [Link]
This is a PIC16F877 based Timer.The outputs consist of a single 7-segment LED display and a piezo speaker . The inputs consist of a 10-position “BCD” rotary switch (for digit entry), two pushbuttons (set and start/stop), and two bits of a 8-position DIP switch (timer selection).
The breadboard on the right of the photo contains the micro-controller (PIC16F877) and most of the other components of the timer. The breadboard on the left contains the serial-port adapter circuit used for programming and the DIP switch.