The MT8870 module designed as a low-power device DTMF decoder chip. This module functions by decoding DTMF signals from an audio source and it is suitable for modem interfaces, remote monitoring applications, telephone answering machines, and more. MT8870 defined as a complete DTMF receiver integrating both the band-split filter and digital decoding functions. This sensor module is a perfect choice for adding dual-tone multi-frequency (DTMF) decoding to your project. Moreover, this detection module capable of interpreting the incoming tone. And produces a coded output, and connects to all manner of microcontrollers.DTMF widely used in touch-tone devices such as a phone. These tones are a combination of two separate sine waves that produce a unique signal that can be transmitted or heard. The module receives this transmitted signal and decodes it. Thereby produce a binary output that used in other devices.
The onboard LEDs present on the module indicates the status of the signals. This MT8870 Tone Decoder designed basically as a multi-frequency decode IC. Soon after it received the DTMF signal, the signal divided into a high-frequency group and low-frequency group and transmitted to the digital decoder. Further, they can figure out the key-value then send it to the outside Bus via four lines( Q1, Q2, Q3, Q4) as the binary form.The DTMF module consists of a 3.5 mm audio input Jack that can be easily connected with a mobile phone by using a 3.5mm audio jack. Moreover, the pins fit standard sockets with a pin pitch of 2.54mm.
For example, by connecting a mobile phone via 3.5mm to 3.5mm cable to the module. When dialing into the phone from a second mobile and then using the keypad will produce the tones on the original phone. Therefore, the tones in the call interpreted by the module, allowing you to control all manner of projects. The MT8870 based DTMF (Dual Tone Multi-Frequency) decoder module widely used to control robots with a mobile phone. Also used in different kinds of home automation projects where mobile dial pad input is required. It is popularly used for mobile and fixed telephone voice dialing and recording related functions.