a simple electronic combination lock using IC LS 7220. This circuit uses a relay for controlling any type of device when the combinations of four digits are pressed. Keypads are used as input here to enter the digits and the correct combination will activate the relay and the door or deice can be operated. The combinat
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ion can be set here by connecting the appropriate keys to the pins 3, 4, 5 and 6 of the IC through Header. Unselected keys are connected to the pin 2. For example if 4568 is your combination then it is to be connected to 3, 4, 5 and 6th pins and rest of the keys are connected to pin 2. Thus any four key combination can be created using this. The 2nd pin of this IC was reset so whenever any other keys connected to pin 2 is pressed it will reset the device and the digits have to be re-entered. When the correct combination is pressed the output will be activated for a preset time determined by the capacitor C1. Increase C1 value to increase on time. Using this circuit you can really construct a high efficient lock system.
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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