The circuit you are about to see is the culmination of some effort at improving the basic Link intercom design. You may think that pulse dialing is `old hat` nowadays, but the exercise of building and testing the Link `P` in this format, and understanding how it all works, is well worth the effort. Not to mention all those out there who have the old
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style rotary dial phones as collectables - you can now make them work for you, or display them actually working with confidence. Counting, pulsing, timing and simple logic circuits are at the heart of this design, as with all other `Link` versions. In a day where PIC controllers are popping up in electronics magazines by the dozen (about half the projects in some magazines now contain a PIC chipset, ) I feel that we could be losing the art of designing in simple `hard wired` logic, and thus this approach is used partly for educational purposes. Many readers who may decide to build up the Link `P` will `see the logic` (pardon the pun) after they have a working model servicing their home, small workshop, factory, preschool or other application. Besides, there`s an easy upgrade to Tone Dialing if you really want it anyway. Happy switching! AH Downunder. This version of the Link goes beyond anything previously attempted by me in the area of telephone type projects. Having achieved genuine ring trip (not that hard, but a bit tricky to design with `off the shelf` $5 components first time around. ) I`m now heading down the track for `two calls at the same time (either two internal calls, or one internal and one external on the outside line - providing it`s legal in your state/country of origin. ) but several things have to be achieved first. In order to achieve a status between two levels of switching for two calls at the same...
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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