Make two telephones ring onstage. This involves sending a signal down a line to the phones. I was hoping to find an old telephone exchange system, but no luck yet. I have found a few ideas for circuits, but would ideally like to make a ringer output that is realistic. This would be about 70-80v at 25Hz. I cannot find any way to make a basic analogue frequency divider, so wonder whether my best bet
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is as follows: We used to use subcycle transformers to generate 30 hz from the 60hz power line. It is basically an LC tuned winding of a transformer. Personally, I think it is easier to just use the power line frequency. Frequency selective ringers for use on party lines (don`t have many of them anymore) operate from 20 hz to 60 hz. No matter which frequency is used with the old two-bell ringers, the tone is going to be the same and I cannot tell the difference between a bell tapping at 60 hz from one operating at 20 hz. Note that the ringer is strictly AC and is blocked from the 48 volt DC talk battery by 0. 1 fd 200 volt capacitor in the telephone`s network. A proper phone ring doesn`t cut off in the same way as an MP3 file. If someone picks up an old bell phone there`s a distinctive "ding" from the handset as it finishes ringing, an echo. If you hear them both you`ll realise the MP3 doesn`t sound quite authentic because of this. By the time you`ve set up the system to work the echo onto the end of the file then also make sure it`s ringing in stereo and sounds as though it`s coming from the stage it makes sense to just make the things ring. FYI: In the US the ringing cycle is 2 seconds on and 4 seconds off. Ringback tone (what the calling party hears) is 1 second on and 3 seconds off. If burst ringing is enabled the first ring can be as short as one second to as long as 3 seconds. The Central Office puts one second of...
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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