Date Range
Date Range
Date Range
Friday, October 2, 2009. This circuit gives out an alarm when its sensor is wetted by water. A 555 astable multivibrator is used here which gives a tone of about 1kHz upon detecting water. The sensor when wetted by water completes the circuit and makes the 555 oscillate at about 1kHz. The sensor is also shown in the circuit diagram.
Saturday, October 3, 2009. These pulses can be picked up by the sensitive amplifier which will cause the circuit to again switch-over states, resulting into motor-boating noise.
Saturday, October 3, 2009. The add-on circuit presented here is useful for stereo systems. 169; Stereo Channel Selector.
Friday, October 2, 2009. This circuit utilising a 555 timer IC can be used as an alarm system to prevent the theft of your luggage, burglars breaking into your house etc. The alarms goes ON when a thin wire, usually as thin as a hair is broken. It uses a 555 IC wired as an astable multivibrator to produce a tone of frequency of about 1kHz which gives out a shrill noise to scare away the burglar. You can even use single strands of copper form a power cable.
Saturday, October 3, 2009. 169; Ultrasonic pest repellent.