DTMF Circuits
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This encoder uses a single contact per key keyboard and provides all other switching function electronically. The diode between terminals 8 and 15 prevents the output going more than 1 volt negative with respect to the negative supply V-.. -
This device allows you to control remotely any (with suitable add-on expansion boards, up to eight) device, such as lights, water heaters (boiler), air-condition, plant watering, alarms, etc via a relay. By using it you can for example water the garden at.... -
DTMF (Dual Tone Multiple Frequency) is associated with digital telephony, and provides two selected output frequencies (one high band, one low band) for a duration of 100 ms. DTMF generation consists of selecting and combining two audio tone frequencies.... -
This version of the Link uses DTMF tones for dialling both internally between handsets, and externally for outside calls. Remember, in some countries, it is ILLEGAL to simply connect unapproved and untested equipment to Telco lines, so avoid the fine and.... -
The circuit uses a NTE1690 DTMF dialer chip and a PIC16F690 microcontroller. Because this is an IP phone and I cannot just send the DTMF tones over the line, the easiest place to plug in the box is between the phone and the handset. The box has two RJ9 ports.... -
The Talking Phone Dial Monitor detects the tones generated when numbers are dialed on your touch tone telephone and speaks the numbers that were dialed. This verifies that you dialed the correct number and is especially useful when the keypad is not.... -
The UNIVERSAL HOLD circuit detects the dual tone, multi frequency (DTMF) tone that is generated when the # key is pressed and then activates a circuit that partially loads the telephone line so that the central office thinks a phone is still off hook even.... -
Here is a teleremote circuit which enables switching on and off of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls. The circuit described here can.... -
Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. This circuit differs from similar circuits in view.... -
The given circuit, when connected in parallel to a telephone, dis- plays the number dialled from the telephone set using the DTMF mode. This circuit can also show the number dialled from the phone of the called party. This is particularly helpful for.... -
I wanted to teach my Arduino to talk telephone, so I added a HT9000A DTMF chip to produce the familiar "touch tones" (upcoming projects will act upon "heard" DTMF tones, but with a different chip). The output is really low volume, so you may want to plug in.... -
The following circuit shows about ?DTMF Remote Domestic System Control Circuit Diagram. Features: DTMF signals can be transmitted over a radio to ... -
This circuit is a circuit diagram of a remote control using DTMF. Actuality we achieve the use of DTMF (dual tone multi-frequency) signals (used the phone to punch in numbers) as the influence of the code. DTMF tones used for the abundance accentuation of.... -
Radio Remote Control using DTMF. Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has... -
A DTMF-based IR transmitter and receiver pair can be used to realize a proximity detector. The circuit presented here enables you to detect any object capable of reflecting the IR beam and moving in front of the IR LED photo-detector pair up to a distance of.... -
This one is using a 16F876 PIC, MCP1047A temperature sensor ( X2 ), MCP1541 voltage reference and MCP6022A opamp. The display is a 2 row HD74780 based 2X16 char, SII L1652BIJ2 but any other display based on HD74780 can be used. Meantime the thermometer is.... -
9-line telephone sharer This circuit is able to handle nine independent telephones (using a single telephone line pair) located at nine different locations, pdf file Bidirectional telephone line simulator without using telephone lines, couple, test and.... -
DTMF dual tone multifrequency The signal is a commonly used signalling in the telephone network, no matter on home telephones, cellular telephones or SPC exchanges, adopt DTMF signal transmission receiving numbers more. DTMF technology can also be used for.... -
Here we make use of DTMF (dual-tone multi frequency) signals (used in telephones to dial the digits) as the control codes. The DTMF tones are used for frequency modulation of the carrier. At the receiver unit, these frequency modulated signals are.... -
Today, most telephone equipment use a DTMF receiver IC. One common DTMF receiver IC is the Motorola MT8870 that is widely used in electronic communications circuits. The MT8870 isan 18-pin IC. It is used in telephones and a variety of other applications..... -
Controlling devices using switches are common. From a few decades controlling devices using remote control switches like infrared remote control switch, wireless remote control switches, light activated switches are becoming popular. But these technologies.... -
Our DTMF decoder can be powered from a 9V battery or from your parallel printer port. It can detect and display all 16 DTMF digits on your computer screen in real-time. The Window`s program can be placed in the minimize mode and still detect tones while you.... -
The main system is the user interface and control system. The phone line was chosen as the method of interfacing because it has distinct advantages over other systems in communicating information from a distance. The next image serves as a block diagram for.... -
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DTMF Touch Tone Decoder Using Microchip PIC Microprocessor This project contains the details of using a Microchip PIC12F683 8 bit microprocessor to detect.... -
The circuit is a remotely operated DTMF telephone. The circuit can be used to change up to 9 devices using the keys 0 to 9 phone. Digit 0 is used to switch between the phone system remotely and change the way of normal conversation. IC KT3170 (DTMF to BCD.... -
This is the working prototype. The eagle files have some minor changes made to it. Fixed some mistakes and re-positioned a few parts. This one is for the phreakers of the past. A simple Arduino shield to decode DTMF tones using an audio input. It can easily.... -
Running the Simple MT 8870 Decoder from your Cell Phone the devise can be operated from any type of DTMF tones like Land Lines, Mobiles, Computers, Radio Transmitters that send DTMF tones over the air waves, Ham Radio sets with DTMF built in to them it has a.... -
Control monitoring equipment at a TV repeater site. It had to accept commands sent as DTMF tones over the repeaters audio channel and be able to switch either AV signals or power supply feeds at currents up to 1 Amp. The switching requirements left no option.... -
This project has an impossible requirement or uses parts that are no longer available. It is here for reference or inspiration only. Consider it unsupported . This project displays telephone numbers decoded from tones. Specifically, telephone touchtones..... -
Today, most telephone equipment use a DTMF receiver IC. One common DTMF receiver IC is the Motorola MT8870 that is widely used in electronic communications circuits. The MT8870 is an 18-pin IC. It is used in telephones and a variety of other applications.....
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New Circuits
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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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