Riju T.

This power saving circuit is used to save electricity while ironing by switching OFF the iron box when it is not in use. Once the on time of the circuit is crossed, it produces an alarm. If we press the reset button at the time of alarm, it is switched off and the on time of the circuit is extended to the next 4 minutes. This circuit works as a reminder for those who always forget to turn OFF the iron box in their busy schedule.

This Arduino based visitor alarm is useful for offices, clinics and shops. It alerts you to the entry of a visitor by producing a beep sound every time the door is opened. The alarm automatically switches off after a few seconds.

Presented here is a simple circuit that uses six red, green and blue (RGB) LEDs to generate a running-light effect in seven colours—blue, green, red, cyan, yellow, magenta and white. The RGB LEDs have four pins, one for each colour and a common cathode. Different colours can be produced by mixing the primary colours (i.e., red, green and blue).