This device and all information contained on this website is for educational purposes only. This device must be used in conjunction with any and all local, provincial and federal laws. It is up to the end user to comply with all legal guidelines, thus we are not and will not be held responsible for any misuse of this product or any damages that it
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may cause. The DTMF decoder is a useful tool used for decoding DTMF (Dual Tone Multi frequency) generated by telephones. The decoded digits are viewed on a 16x2 LCD screen. A interface can be connected between the DTMF decoder and a Serial port to view the digits in Hyperterminal on a computer. The decoder stores the last 255 received digits in EEPROM. The contents of EEPROM can be viewed on the LCD screen via two scroll buttons. Total power consumption is 17mA. The DTMF decoder has three inputs. A RJ11 jack for connecting to the phone line. A 1/8" audio jack for connecting to a scanner, tape recorder or other audio output device. A microphone with a 6-12" range. A PCB layout is provided if one wishes to construct their own PCB. Simply print the file at 1:1 onto an overhead transparency. (Get the correct sheet for your type of printer) I used a kit by MG Chemicals ( E-Sonic Search for 416-K) to produce my PCB. The provided PCB layout`s smallest traces are 15 thou wide. Drill the holes for the headers at 40 thou. Drill the holes for the 20K POT, the buttons, and the audio jack at 35 thou. Drill the rest of the holes at 30 thou. Drill bits can be found a most hobby stores. Review the schematic and parts placement diagram before beginning assembly for proper orientation of diodes, ICs and capacitors. Begin by installing the seven jumper wires. Next solder in all the resistors and capacitors. Then solder in the buttons, the...
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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