Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

DTMF Remote control – A software DTMF decoder for PIC 16F87X

DTMF Remote control – A software DTMF decoder for PIC 16F87X

The DTMF detector is integrated in software. All the logic requested to receive and decode DTMF Commands over the phone line is integrated in the 16F877 chip.
only few external components are used. As soon as possible I plan to switch to a 16F629-20 Pic and like that will be a Single Chip DTMF Remote Control. The debug possibilities of 16F877 made him a good choice in order to develop the application. Once the development is finished the downsize to a smaller Pic will reduce the cost and integrate the Comparator to.

The Line interface is designed to share the Phone Line with an Answering Machine; no supplementary Phone line is requested.

The Remote control has 4 Outputs capable to drive 10 Amps at 120VAC and accepts three simple commands – Set/Reset Output, Check Output Status and Change Password via DTMF digits.

The hardware consists in the phone line interface and the relay drivers.

All the logical functions are integrated in the 16F877 micro controller.

The line interface was built as simple as possible. The purpose of this interface is to permanently monitor the Phone Line for incoming DTMF signals, output confirmation Beep’s to the line and keep the phone loop closed while the DTMF Remote is in use.

The phone line is connected at the JP1 jumper. R3, C1, line trafo and D2 are protecting the rest of the DTMF detector from the ringing signal and other power spikes coming from the phone line side. C1 should be a good quality capacitor designed for 250VAC at least. D2 should be a 1W – 5.1V zener diode in order to absorb all the power spikes.

The ground of the DTMF Remote must be floating in order to work as expected and cannot be connected to earth ground.

Visit Here for more.







 

More Articles to Read

Free PCB coupon via Facebook to 2 random commenters
Free PCB coupon via Facebook to 2 random commenters
Design for a Wideband, Differential Transimpedance DAC Output
Design for a Wideband, Differential Transimpedance DAC Output
Blinking Christmas Lights
Blinking Christmas Lights
Wrist thrusters let you fly through the water effortlessly
Wrist thrusters let you fly through the water effortlessly
Bertan/Spellman 225-20R HV power supply teardown
Bertan/Spellman 225-20R HV power supply teardown
Blinking Christmas Lights
Blinking Christmas Lights
Adjusting clock with alarm, hygrometer & thermometer on 1.8″ ST7735 display
Adjusting clock with alarm, hygrometer & thermometer on 1.8″ ST7735 display
Adding an “extra sense” with rangefinders
Adding an “extra sense” with rangefinders
This wireless game controller looks like a rug
This wireless game controller looks like a rug
How to run your ESP8266 for years on a battery
How to run your ESP8266 for years on a battery
Calibration of a 3-Phase Energy Meter Board on the ADE7754
Calibration of a 3-Phase Energy Meter Board on the ADE7754
Making beats on a tiny Arduino DJ controller
Making beats on a tiny Arduino DJ controller
Qinsi-QS5100 Sn63Pb37 solder profile
Qinsi-QS5100 Sn63Pb37 solder profile
Water Detection System
Water Detection System
Professional Hi-Fi 15W Tube Amplifier circuit
Professional Hi-Fi 15W Tube Amplifier circuit
This Arduino machine will judge how sick your ollies are
This Arduino machine will judge how sick your ollies are
Turn an old payphone into a boombox for ’90s hits
Turn an old payphone into a boombox for ’90s hits
Big F’n 3D printer build
Big F’n 3D printer build
Temperature alarm for boiling milk
Temperature alarm for boiling milk
QuadBot is a 3D-printable walking robot for everyone
QuadBot is a 3D-printable walking robot for everyone

Top


Shares