Wednesday, October 30, 2013
Here's a useful circuit, he is a TTL square wave oscillator, it uses three logical ports, and also a capacitor and a resistor to adjust the frequency. The circuit can be used as a Clock Oscillator, standard signal, etc. The oscillator uses a 7400 integrated circuit, the table below shows the values of C * and R * to achieve the desired frequency, which can be chosen between 100 hz and 1 MHz
Tuesday, December 18, 2012
With this sound activated switch, control by sound may be very useful, not just on a robot but also for a bit of home automation, for example a sound-activated light responding to a knock on the door or a hand clap. The light will be automatically switched off after a few seconds. An alternative use is burglar protection — if someone wants to open the door or break something the light will come on, suggesting that someone’s at home. The circuit can work from any 5–12 VDC regulated power supply provided a relay with the suitable coil voltage is used.