CM8870 REMOTE DEVICE CONTROL VIA TELEPHONE DTMF PIC16F628

Summary of CM8870 REMOTE DEVICE CONTROL VIA TELEPHONE DTMF PIC16F628


This article describes a DTMF-based remote control system using the PIC16F628 microcontroller and CM8870 IC to operate up to four relays via mobile phone calls. The system allows users to toggle individual or all relays by pressing specific keypad numbers, with status indicated by LEDs. It features password protection, automatic call answering after three rings, and EPROM memory to retain relay states during power failures.

Parts used in the DTMF Remote Device Control System:

  • PIC16F628 microcontroller
  • CM8870 integrated circuit (DTMF decoder)
  • Four relays
  • LED indicators for relay status
  • Mobile phone with audio output
  • EPROM memory module
  • PCB printed circuit board
  • Picbasic software files
  • Micro Code Studio programming software

PIC16F628 microcontroller and DTMF CM8870 integrated circuits based on the 1, 2, 4 relay has versions with PCB printed circuit drawings ares proteus software prepared by the Picbasic. Source code, the PCB according to… Electronics Projects, CM8870 Remote device control via telephone DTMF pic16f628 “microchip projects, microcontroller projects, pic16f628 projects, picbasic pro examples, “

REMOTE DEVICE CONTROL VIA TELEPHONE

PIC16F628 microcontroller and DTMF CM8870 integrated circuits based on the 1, 2, 4 relay has versions with PCB printed circuit drawings ares proteus software prepared by the Picbasic. Source code, the PCB according to the drawings, as well as different operating scenarios given in Picbasic software files.

For sharing Şükrü ÖZKARABACAK I thank my teacher rests with the explanations below

REMOTE DEVICE CONTROL (1)

REMOTE DEVICE CONTROL (2)

REMOTE DEVICE CONTROL (3)

DTMF CONTROL SYSTEM STUDY (DTMF 4 RELAY)

Thanks to this control card with you in your mobile phone, the relay contacts depending on the 4 pieces you can control the device independently of each other.

If we give an example tarlanızda 4 get home or water engine by calling the system from where you are if you want to turn on or off the water engine. In short, you can check the relay circuit only by contacts of relay “runs everywhere.

Operation of the system are as follows: cell phone control card is connected to the audio input of a mobile phone’s headphone output. This mobile phone menu, three times when I open the phone the cheapest phone available on the market with the automatic.

We own a cell phone and is set as the key tone tone control board, obscured by the phone. This phone has already arranged to play three times and the phone opens. In the aftermath of their own during after the following operations is performed by tuşlamalar.

# 1 TAKES the No. 1 RELAY
* 1 LEAVES the No. 1 RELAY

# 2 number 2 RELAY PULLS
* 2 the number 2 LEAVES the RELAY

# 3 3 RELAY PULLS
* 3 number 3 LEAVES the RELAY

# 4 PULLS the RELAY number 4
* 4 LEAVES the RELAY number 4

11 all RELAYS PULLS
33 LEAVES ALL the RELAYS

There is a relay on the card belongs to each led. This led to what is known as the relay you can visually active or passive. Except for the fifth relay is four illuminated mimic diagram turns from the phone keypad, voice system demand led so it shows the DTMF tone detected by the system. As long as the key is pressed every key detected voice this led lights up.

The relay open – close all saved in eprom memory operations. When it comes to the processing power of a possible power failure the system will resume. If desired, eprom memory feature can be canceled. We will bear in mind the above passwords. On request we can change these passwords and passwords that you specify. In addition, you will use the system requires software support for different program features included, please contact us.

HOW TO CHANGE PASSWORDS?

A program called Micro Code Studio is installed on the computer. This program wise and windows7 installation work on computers. XP installation on the computer is working fine. After the program is installed. Pressed opens the file extension. Through the opened file has the following sections

 SIFRE:	
           PAUSE 10	
  	IF c1=12 AND c2=3 AND c3=6 AND c4=3 THEN   
           SIFRE_1=1  
           ENDIF
           IF c1=12 AND c2=3 AND c3=6 AND c4=5 THEN   
           SIFRE_1=0
           ENDIF

In the example above opening password type # 363 # 365 tractor shutdown password. DTMF digits values are as follows.

1 => 1
2 => 2
3 => 3
4 => 4
5 => 5
6 => 6
7 => 7
8 => 8
9 => 9
0 => 10
* => 11
# => 12
A => 13
B => 14
C => 15
D => 0

Let’s open the 1453 closing of the above code will change in 2015.

    SIFRE:	
           PAUSE 10	
  	IF c1=1 AND c2=4 AND c3=5 AND c4=3 THEN   
           SIFRE_1=1  
           ENDIF
           IF c1=2 AND c2=0 AND c3=1 AND c4=5 THEN   
           SIFRE_1=0
           ENDIF

Source: CM8870 REMOTE DEVICE CONTROL VIA TELEPHONE DTMF PIC16F628 DTMF Relay Controller PCB and code files belonging to the project: CM8870 Remote device control telephone DTMF pic16f628.rar

Quick Solutions to Questions related to DTMF Remote Device Control System:

  • How does the system answer incoming calls?
    The system is configured to automatically open the phone menu and answer after receiving three rings.
  • What happens when I press number 1 on the keypad?
    Pressing 1 pulls (activates) Relay 1, while pressing it again leaves Relay 1 inactive.
  • Can I control all relays at once?
    Yes, pressing 11 pulls all relays, and pressing 33 leaves all relays inactive.
  • How can I visually check which relay is active?
    Each relay has a dedicated LED that lights up when the relay is active or passive.
  • Does the system save relay states if power fails?
    Yes, relay operations are saved in EPROM memory so the system resumes the correct state after power restoration.
  • How do I change the system passwords?
    You must use Micro Code Studio to edit the source code file and modify the SIFRE section values.
  • What value represents the hash symbol # in the code?
    In the DTMF digit mapping used by this project, the hash symbol # corresponds to the value 12.
  • Which software is used to prepare the source code?
    The source code and PCB drawings are prepared using Picbasic software.

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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