This lie detector circuit can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie. [...]
A light/dark analysis ambit is acutely advantageous and able in a advanced ambit of renewable activity projects from automated lighting to aegis systems. In our commodity Ablaze Dependent Resistor we explained how an LDR can be acclimated in simple circuits to ascendancy accessories according to the ambient levels of lighting – for example, automatically axis [...]
Digital LCD Thermometer Circuit At this thermometer, the IC thermo sensor (S8100) or the diode (1S1588) is acclimated as the thermo sensor. Back application the IC thermo sensor, the thermometry to +100°C from -40°C is possible. Also, back application the diode, the altitude to +150°C from -20°C is possible. Both sensors are independent in the [...]
This simple circuit can be used as an aid for sensing the distance between the rear bumper of the car and any obstacle behind the car. The distance can be understood from the combination of the LEDs (D5 to D7) glowing. At 25cm D7 will glow, at 20 cm D7&D6 will glow and at 5cm [...]
Here’s a fire alarm circuit using LDR (Light Depending Resistor) as light sensor. It warns the user against fire accidents. It relies on the smoke that is produced in the event of a fire. When this smoke passes between a LED and an LDR, the amount of light falling on the LDR decreases. This causes [...]
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 [...]
