This alarm circuit is an anti- theft wireless alarm can be used with any vehicle having 6- to 12-volt DC supply system. The mini VHF FM radio-controlled, FM transmitter is fitted in the vehicle at night when it is parked in the car porch or car park. The receiver unit of the wireless alarm uses [...]
This is a really small alarm that could easily fit inside a pocket. However, I also demanded reliable operation, simple construction and very low power consumption. I started with CMOS logic gates, but was soon forced to abandon the concept after a few unsuccessful (and far too complicated) takes. Then I suddenly realized that a [...]
Rain alarm is a simple circuit using water sensor (transducer) that produces an audible alarm whenever rain falls. The circuit can be based on two transistors and or a NE555 IC. The two transistors are wired as a switch which goes on when the base of Q1 is shorted to the positive of the supply [...]
Fire Alarm Circuit Using LDR Here is a simple fire alarm circuit based on a LDR and lamp pair for sensing the fire.The alarm works by sensing the smoke produced during fire.The circuit produces an audible alarm when the fire breaks out with smoke. When there is no smoke the light from the bulb will [...]
Water Alarm Level Indicator Circuit Versatile circuit which indicates the level of water in a tank. This circuit produces alarm when water level is below the lowest level L1 and also when water just touches the highest level L12. The circuit is designed to display 12 different levels. However, these display levels can be increased [...]
The circuit is small regulatorof temperature, us warns for the increase of temperature. The control of temperature becomes from the thermistor TH1, that is negative factor. His resistance is altered between in the 10K in temperature 25° C and roughly in the 1K in their 94° C. The trimmer TR1 regulates the precise temperature in [...]
