The laser-pointer detection circuitry is able to determine when a laser light is aimed at a particular photosensor. If the laser is aimed at the top sensor, the comparator chip outputs on . If the laser is aimed at the bottom sensor, the comparator chip outputs off . The circuit could be considered complete if you wanted somethi
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ng to be turned on only while the laser is aimed at the on sensor. However, if you want the circuit to remember whether the on sensor or the off sensor was most recently selected, then you`re going to need to hook those outputs to a memory chip. Looking back at the schematic, you`ll notice that the output names of on and off have little lines above the words. Usually an output is high (5V) when a condition is true, but the line above the word means the output is low (0V) when the condition is true. The line stands for opposite , not , or negate . The reason that the comparator has been wired to do this is because the memory chip on this page needs the information in that format. However, should you have a circuit that needs normal outputs, simple swap IC1 pin 5 with IC1 pin 6, and IC1 pin 2 with IC1 pin 3. Flipping the input pins on the comparator provides the opposite output. This circuit only needs to remember whether the final output should be on (5V) or off (0V). This is the smallest, most rudimentary amount of memory. It is called a bit ; which stands for binary digit . A bit can only be on or off. The 7474 chip is a basic logic chip that contains a 1-bit memory cell. For convenience, just like the comparator chip on the previous page, the 7474 includes two independent copies of this feature on a single chip. Therefore, the 7474 has two independent 1-bit memories on the chip. We only need one bit for this...
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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