This 3-digit digital thermometer is easy to build for beginners or hobbyits. PIC16F628 is used to read digital values of temperature from a DS1820 sensor. All 7-segments are driven by a power logic 8-bit shift register TPIC6B595 with open collector output. For the 7-segment we need 12V volt to drive it because it has 3 LED per one segment. Source code in C Compiler is available.
3-Digit Digital Thermometer: [Link]
Interfacing an Analog-to-Digital Converter (ADC) with Linux via the parallel port is fairly simple. There two major areas that need to be addressed - hardware and software. The hardware consists of the parallel port, an ADC, and an analog signal source. The software we programmed in ‘C’ language.
Interfacing Your Computer to an ADC via the Parallel Port: [Link]
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]
This barometer uses the absolute pressure sensor MPXA4115A, 12-bit A/D converter and AVR ATmega8. The source code and schematic are here. The result is displayed on graphical LCD with TOSHIBA T6A04 controller. In the first half are numerical value of actual pressure in milibars and on second half are bars that represent pressure in last 30 hours (15 bars with 2 hours measuring period). horizontal antermittent line represent pressure of 1000 mb.
Digital barometer: [Link]
This innovative dsPIC30F2020-based project showcases an interesting approach for reducing speaker distortion and increasing bass response. A dual-coil speaker driver is implemented in the design, but only one of the coils is connected to the power amplifier. The other coil is used for electromotive feedback.
This is not a new idea, but many do not implement it due to the multitude of factors that have to be counted for the analog signal.
Digital Subwoofer Amplifier with Electromotive Feedback Reduces Distortions: