This digital thermometer use DS1820 measurement temperature from 0-99 ‘C then the temperature will display on LCD 1X16 .The CPU used in this project is PIC16F84A. Software programming with CCS C Compiler. Download CCS Source code

This circuit uses an MC2830 to form a voice activated switch ( VOX ). A traditional VOX circuit is unable to distinguish between voice and noise in the incoming signal. In a noisy environment, the switch is often triggered by noise, or the activation sensitivity must be turned down. This circuit overcomes this weakness. The [...]

From http://www.elecfree.com/circuit/electronic-control/sound-scr-swith-by-ic-1458-scr-c106d/

We have all seen the commercial on TV ………. CLAP – ON – CLAP – OFF – THE – CLAPPER ………… well here is a circuit that will perform that same function. Circuit operation is as follows. A single hand clap will be picked up by the electric mic which is coupled through C1 into [...]

There is a lot more to designing an FM transmitter, than meets the eye. Here is a typical FM transmitter circuit. It consists of 3 stages. An audio amplifier, RF Oscillator and RF output. Read More Source : http://www.talkingelectronics.com/te_interactive_index.html