Dark Detector with LM555
The dark detector circuit utilizes the LM555 timer IC configured in a monostable mode. In this configuration, the circuit is designed to produce an output pulse when triggered by the absence of light detected by the CdS sensor. The CdS sensor exhibits a high resistance in darkness and a low resistance in light, effectively acting as a variable resistor in the circuit.
When the light level decreases below a certain threshold, the resistance of the CdS sensor increases, which can be used to trigger the LM555 timer. The timer's output can be connected to a speaker or buzzer, generating an audible sound to indicate the dark condition. The duration of the sound can be adjusted by changing the timing components (resistor and capacitor) connected to the LM555.
To construct the circuit, the following components are necessary: an LM555 timer IC, a CdS light sensor, a resistor (for setting the threshold), a capacitor (for timing), a speaker or buzzer, and a power supply. The circuit should be designed to ensure that the CdS sensor is adequately shielded from direct light to prevent false triggering.
In summary, this dark detector circuit effectively utilizes the properties of the LM555 timer and the CdS sensor to create a simple yet functional device that signals the absence of light through sound, making it useful in various applications where light detection is critical.Dark Detector with LM555 . This is a dark detector circuit. This circuit will generate sound if no light source and silence when light falling on CdS. CdS : Cadmium sulphide or cadmium. 🔗 External reference
Related Circuits
This project involves a simple metal detector circuit that is easy to construct using a single transistor and a few additional components. The circuit operates as a Colpitts oscillator, broadcasting on the AM band. To use it, place a...
This circuit serves as an alternative to the infrared (IR) beam break detector featured in the June 2009 issue of Silicon Chip. It utilizes a standard IR receiver IC, such as the Jaycar ZD-1942, to minimize sensitivity to ambient...
A positive-going input charges capacitor C through the IN4148 diode and resistor R. The diode ensures that the silicon-controlled switch (SCS) remains off. A negative-going input provides anode-gate current, which triggers the SCS, allowing capacitor C to discharge through...
Clipping is a significant issue that leads to distortion in amplifiers. It results in the amplitude level of a waveform dropping abruptly before it reaches its intended limit. This document presents a straightforward circuit designed to detect clipping in...
This smoke detector employs a MEM 817 p-channel enhancement mode MOSFET as its buffer amplifier. The sensor operates on the principle that the current decreases when smoke enters the chamber, leading to a negative voltage change at the gate...
A PIC microcontroller and an LCD have been integrated into a basic radiation detector, enabling the display of total counts over a 24-hour period or counts per second, as well as the relative gamma strike energy level. The energy...