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 [...]
Radio Clock listens to radio time signals from your radio and corrects the time on your PC clock. Radio Clock enables you to decode the time signals sent by various LF and HF radio stations in the standard frequency and time service. Radio Clock uses your PC to display the time code received from the [...]
It’s a simple metal detector design that has the quite good characteristics. the principle of operation which one differs from the classic schemes (BFO, transmit-receive known as “two-boxes” metal detector, inductive). The dynamic mode is used to find targets in interference environment. There is known from theory of signal filtration that if signal shape is [...]
This Sensor circuit was designed as an aid in parking the car near the garage wall when backing up. LED D7 illuminates when bumper-wall distance is about 20 cm., D7+D6 illuminate at about 10 cm. and D7+D6+D5 at about 6 cm. In this manner you are alerted when approaching too close to the wall. All [...]
This is a simple fire alarm circuit based on a LDR and lamp pair for sensing the fire. It uses a very simple approach to detecting smoke in the air. The alarm works by sensing the smoke produced during fire.The circuit produces an audible alarm when the fire breaks out with smoke. This probably isn’t [...]
Here’s a alarm clock circuit based on PIC Controlled. Two circuit boards put together a simple PIC based design comprising of two interlinked vero-board cards. The larger of the two circuit boards holds the 5V power regulator, the display processor (a PIC 16F74), the real time clock (Dallas DS1307), 3V backup battery and buzzer. See [...]
Here’s a simple home alarm circuit is for those who are eager to know the concept of home security system. It consists of three 555 timers gets the input from a contact that could be connected to a motion detector or any momentary contact that monitors a certain process. Once the contact is momentarily closed, [...]
