The circuits presented here will prevent turnouts from being thrown while a train is on a switch, ideal where the switch cannot be seen by the operator. They use phototransistor sensors to detect the train and have a short time delay to compensate for gaps between cars. The circuit can also be used to protect crossovers and ladder tracks with the
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addition of more sensors. There are two versions, the first uses push buttons and is for twin coil switch machines. The second uses a toggle switch and can be adapted for other types. The main difference between the circuits is that the second version contains a `memory` function that will allow delayed throwing of the turnout until after the train has cleared the switch. The Push Button version of the protection circuit simply disconnects the switch machine from its power source when ever a train is on the switch. This circuit could be used for Twin Coil type machines When the voltage across the capacitor reaches 1/2 of the supply voltage the output of IC 1b will go HIGH and the relay will be turned off. (The time required to charge the capacitor to this voltage is 6 to 8 seconds. ) This version of the protection circuit replaces the mechanical relay with an SCR, (Silicon Controlled Rectifier). The SCR will allow easier `PCB` construction of the circuit and may be cheaper to build as well. The advantage of using a relay versus an SCR for the output is that the switch machines will still operate if the protection circuit has no power or fails. When no current is flowing through the optoisolator`s LED its output transistor will not conduct and the gate of the SCR will not be able to trigger. When either of the push buttons is activated no current will flow to the coils because the SCR cannot turn on. When the voltage across...
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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