My Light Diagram

The following post illustrates a simple light toggled/operated remote control circuit, which can be activated by an ordinary flashlight or more effectively through a laser beam unit (key chain type). The circuit idea may be understood with the below mentioned points: Transistor T1 alnog with R3, C6 and the LDR itself forms a simple light sensor stage.  The LDR is connected across the base of the transistor and the positive supply such that when light falls over the LDR, T1 receives the required base bias and conducts.  When T1 conducts, the high potential at pin 14 of IC1 is pulled to logic low. However since a logic low wouldn't effect pin#14, IC1 does not respond as yet. The moment light on the LDR is switched OFF, T1 is switched OFF and pin#14 now instantly receives a subsequent logic high via R5.....now IC1 responds, and shifts it's output from pin#3 to pin#2. This makes pin#3 logic low, activating T2, and the preceding relay driver stage. The above condition pers...

This circuit is built around a 555 timer using very few components. Since the circuit is very simple, even a novice can easily build it and use it as a controlling device. A laser pointer, now easily available in the market, can be used to operate this device. This circuit has been tested in operational conditions from a distance of 500 meters and was found to work satisfactorily,though it can be controlled from still longer distances. Circuit diagram : Laser Controlled ON/OFF Switch Circuit Diagram Aiming (aligning) the laser beam exactly on to the LDR is a practical problem. The circuit is very useful in switching on/off a fan at night without getting off the bed. It can also be used for controlling a variety of other devices like radio or music system. The limitation is that the circuit is operational only in dark or dull lit environments. By focusing the laser beam on LDR1 the connected gadget can be activated through the relay, whereas by focusing laser beam on LDR2 we can switch...

Rotating laser levels, which are very handy  for setting objects in a room or garden at the  same height, are available at prices of a few  dozen pounds. At relatively large distances  and for outdoor use, the light from the rotating laser beam is often not easy to see, and  the laser beam detector described here can  be useful in such situations. The detector  works well at distances up to 50 metres (150  feet) and consists entirely of standard components. The detector is housed in a plastic case  that can be fixed to an object (such as a post  or a beam). It has three LEDs and a beeper that  indicate whether the object should be raised  or lowered. LEDs with a transparent package and integrated lens (round surface) are used as sensors. The top and bottom detection zones  each have five LEDs and two opamps (IC1a &  IC1b or IC1c & IC1d), which drive the ‘Move  Up’ and ‘Move Down’ indicator LEDs. The middle sensor LED drives the ‘OK’ indicator LED  via two opamps (IC2a & IC...