laser trip wire circuit
The Afrotechmods laser tripwire circuit is an innovative application of basic electronic components to create a security system that detects interruptions in a laser beam. The circuit operates by using a laser pointer to emit a beam of light directed towards a photodetector, which is typically an LDR. When the beam is interrupted, the change in light intensity at the LDR triggers the MOSFET, which can control a load, such as an alarm or a light.
In this circuit, the IRF244 MOSFET serves as a switch. When the laser beam is uninterrupted, the LDR maintains a low resistance, allowing a small current to flow through a voltage divider formed by the LDR and a resistor. This small current keeps the MOSFET in the OFF state, preventing the load from being activated. However, when an object or person interrupts the laser beam, the light hitting the LDR is reduced, causing its resistance to increase. This change in resistance alters the voltage across the MOSFET gate, turning it ON and activating the load.
The circuit can be enhanced by selecting appropriate resistor values to fine-tune the sensitivity of the LDR. Additionally, incorporating a capacitor in parallel with the LDR can help stabilize the circuit and prevent false triggering due to momentary disturbances in light. The layout of the circuit should ensure that the laser pointer and LDR are aligned precisely to create an effective tripwire.
This application of a laser tripwire circuit is not only a practical project for hobbyists but also serves as a foundation for more complex security systems. By understanding the principles behind this simple circuit, one can explore further enhancements, such as integrating microcontrollers for more advanced functionalities or wireless communication for remote monitoring.A replication of Afrotechmods laser tripwire circuit. Using a simple laser pointer, IRF244 MOSFET ( most NPN transistors would do the job), a couple of resistors and one LDR 🔗 External reference
Related Circuits
The 555 is wired as an astable and the capacitor is charged only through the 4.7Kohm trimmer (notice the diode) and discharged only through the 2.2 Kohm trimmer, making the duty cycle fully adjustable. The square wave is then...
This is a straightforward charger designed for 9V to 30V batteries, primarily operated by the IC LM317L and a 2N222 transistor. It utilizes direct input DC voltage, and a recommended capacitor of 1000µF is included for filtering the output...
This schematic requires clarification. It is assumed that pin 2 is connected by a wire to pin 6, although this connection appears to be unclear. The circuit in question involves a schematic where pin 2 and pin 6 are interconnected....
The mechanical chassis prototype, as illustrated in the accompanying image, was constructed using two materials: foam and aluminum. Foam was selected for its ease of manipulation, while aluminum was chosen for its excellent strength-to-weight ratio. The prototype features a...
The proposed approach would dissipate (12V)(3A) = 36 watts, which results in significant heat generation in the circuit. This necessitates consideration of two alternatives: 1) Operating the op-amp at a lower supply voltage, if feasible, or 2) Utilizing a...
This circuit provides a straightforward and efficient method for interfacing two relays in switching applications. The relay driver utilizes a standard BC547 NPN transistor (or equivalent) to enhance the input impedance. It is a widely used driver capable of...