A stereo cable with stereo plugs (TRS) 3.5 "is used to connect the decoder.
For wireless DTMF control, it is possible to use all kinds of FM transmitters and receivers.
This is anevaluation board for the Silicon Laboratories Si4703 FM
M tuner, which performs filtering and carrier detection.
DTMF is controlled using the 8870. 16-channel decoder and its modifications. - The module for converting frequency-pulse two-tone modulation into a 4-bit logic signal; - Connects to the line output of an internal or external USB sound card;
- IO Drive : Sink Current (Low level drive) 20mA, source current(High level drive) 270uA;
- 16 Channel selectable high and low level output. 16 Channel output: 0-9,*# ABCD;
- 8 kinds of Mode selection;
- Response rate in a cycle of 50 -70 ms; - DC Power Supply Voltage:4.5V-5.5V (Tup: 5V).
STM32F103 ADC module USES a series of single chip microcomputer STM32 10 road of the internal ADC 10 road resources as core sampling, takes to the sampling data by STM32 internal DMA transfer to memory, reduce the financial burden of the CPU and enhance the stability and accuracy of the AD sampling, at the same time onboard turn USB serial data transmission can be first place machine chip. Function characteristics: The onboard STM32F103C8T6 master control chip; Onboard CH340 a serial port turn USB chip, convenient through the USB port on the PC to check the AD sampling results; Reserve a UART serial communication interface, can answer the MCU; Analog input channels: 10 channel single-ended input; Sampling the voltage input range: 0-3.3 V. Power supply voltage: 5 V / 3.3 V Resolution: 12 Bit (4096); The board size: 50 * 33 mm 1, the interface description: IN0 - IN9: AD sampling voltage input; GND: negative/sampling voltage interface; The TX and RX: UART communication interface Reserve 3 v3/5 V: 3.3 V / 5 V power supply input port