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DTMF Decoder Interfacing with ATmega16 and LED Display
DTMF is as acronym for Dual Tone Multi-frequency Signalling. It is used in telecommunication signalling, basically it is a signal that is sent to the switching centre (phone company) when the phones keys are pressed. DTMF is also called as Multi Frequency Signalling because for each key you press two tones of specific frequencies are generated. This is done so that a voice cannot imitate the tones. One tone is generated from a high frequency group and the other from a low frequency group with duration of 100ms. In all there are 16 DTMF tones but currently only 12 tones are being used in our phones. At the switching centre, an electronics circuit called DTMF decoder is used to decode or to know the value of the pressed key. The DTMF decoder gives 4-bit signal as the output.
In this project, we will learn How to interface a DTMF Decoder with AVR ATmega16 microcontroller and LED display. Here, we will find the value of the key pressed in a mobile through DTMF Decoder and we will display the value of the pressed key in a 1X8 LED array. In this project, we will use two mobiles, one will be connected with the DTMF circuit and another will be used to call the mobile attached with DTMF circuit. The Mobile attached with DTMF circuit will be kept in auto-answering mode. The DTMF decoder can decode DTMF signal of both mobiles. The user will press different keys of the mobile attached with the DTMF circuit and the DTMF Decoder will decode the DTMF signal of mobile. After decoding the DTMF signal, the DTMF decoder will output a 4-bit value. AVR ATmega16 microcontroller will read this 4-bit output of DTMF decoder and will process it to find the value of the pressed key. After processing the DTMF output, the microcontroller will display the value of the pressed key in the 1X8 LED array. Now, we will press different keys of the attached mobile and we will see the changes in LED array. After doing the above process, call the mobile attached with DTMF circuit from the other mobile. After the Call is being received, press keys from the calling mobile and see the changes in the LED array.
Softwares Required
Hardwares Required
| Name | Quantity |
AVR Trainer Board-100 with ATmega16
|
1pc |
AVR USB Programmer
|
1pc |
12V, 1A DC SMPS Adaptor
|
1pc |
DTMF Decoder
|
1pc |
3.5mm Audio Jack with Connector
|
1pc |
10 to 10 FRC Female to Female Connector
|
3pc |
Circuit Diagram
Video
Connection Guide
The step-by-step connection guide for DTMF Decoder Interfacing with ATmega16 and LED Display is as follows
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Steps - 1 ( 0f 8 )
Insert the DC Pin of 12V, 1A DC Adapter to the DC Socket of AVR Trainer Board-100.
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Steps - 2 ( 0f 8 )
Connect PortB header with LED data header in AVR Trainer Board-100 with a 10 to 10 FRC Female Connector.
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Steps - 3 ( 0f 8 )
Connect RS, RW & EN pins of LCD control header with PD0, PD1 & PD2 pins of PortD header respectively in AVR Trainer Board-100 with 1 to 1 Connectors.
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Steps - 4 ( 0f 8 )
Insert the 3.5mm Audio Jack to Mobile Earphone Socket and Female Connector to DTMF Input pins of DTMF Decoder Board.
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Steps - 5 ( 0f 8 )
Connect the ISP header of AVR Trainer Board-100 with AVR USB Programmer header of AVR USB Programmer with a 10 to 10 FRC Female Connector.
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Steps - 6 ( 0f 8 )
Connect the AVR USB Programmer to the PC/Laptop's USB Port directly or with the help of USB AM-AF Cable.
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Steps - 7 ( 0f 8 )
Switch on the power with the help of Power Switch of AVR Trainer Board-100.
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Steps - 8 ( 0f 8 )
Download DTMF Decoder Interfacing with ATmega16 and LED Display Hex file to AVR Trainer Board-100 with the help of SinaProg Hex downloader and AVR USB ??Programmer.
Downloads
DTMF Decoder Interfacing with ATmega16 and LED Display Project File
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