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47 Threads found on Dtmf Control
Hello, I would like to control a device, using dtmf commands that are modulated in FM at an RF carrier of 144MHz. So I need a suitable receiver that can demodulate 144MHz FM into dtmf tones. Then I will handle the dtmf tones to switch things on the device. What is the simplest design I can build? The receiver will only be (...)
I don't exactly understand the problem. dtmf dialing is always performed in off-hook state. Besides primary dialing, dtmf tones are often used to control automatic voice mail systems etc. during a call, just pressing dial keys.
I know that we can control the output connected to the 8051 ports through mobile by interfacing dtmf decoder 8870 with 8051 .....but can i get information of some inputs connected to the 8051 to my mobile by interfacing any other device with 8051??..... if yes ,please help me out by informing about that device.......?
Once i did this but i remember i use a control loop that was marginally stable, so then i had to just change some parameters so that the oscillation frequency where the dtmf ones. If you want to know how many point sdo you need, you should try matlab first, check this with a real telephone putting the mic on the computer speaker. Once you got a d
Hi everyone, i am using proteus program to design circuit of mobile control robot but the problem, there is no chip of dtmf (CM8870 IC) decoder in the program.. what other choices i can use instead of that chip??!
Hi, I need a complete project that will make use of a gsm to control 6 loads through dtmf. I will appreciate if the microcontroller is either AT89S52 or any PIC. Please include both the circuit diagram and the code thanks.
hi i am trying to control devices using dtmf and 89s52, the code i wrote is #include /*MOTOR*/ sbit rm1 = P0^0; sbit rm2 = P0^1; sbit lm1 = P0^2; sbit lm2 = P0^3; /**/ sbit led1 = P1^0; sbit led2 = P1^1; sbit led3 = P1^2; sbit led4 = P1^3; unsigned char z=0,y=0,value=0,tem=0,hum=0,i=0,hum1,j=50,l=0; bit flag=0; un
Circuit is bad, what you plan with thise diodes on output ? See circuit examples : www.radiolocma
Its possible. Almost every GSM phone can generate dtmf codes. But why to use dtmf codes, you need to establish connection, you can use SMS control.
Actually I am making dtmf remote control. So for that I needed auto answer support mobile phone. So I am not getting which to be used. I have searched on Google but found zero answers! any help would be appreciated. Thank you.
The dtmf frequency specifications are well documented on the Web. You will also find dtmf algorithms and sample code in assembler and C. Why do you not you use a tone decoder/encoder chip?
Please I urgently need a working circuit and source code for a dtmf(eg.8870) and AT89S52 to control 4 relays(ON and OFF as desired) connected on Port2 of the AT89S52. The dtmf should be fed to port3 of the AT89S52. The Relays should be turned ON by the pressing of keys 1,2,3 and 4 respectively but can be Turned OFF by ke
I'm using MT8880 to generate dtmf tones only. My question is how should I terminate the IN+, IN-, GS, Vref, Est, St pins which I won't be utilizing. Thank you
Hi all, ı cant enabled the dtmf decoder in sim900D what's the AT commands pls hlp me :(
Hi Friends, i am doing voice call based device control using GSM & dtmf. i connect the speaker input line into dtmf input , my headset is response the call and dtmf tone but MT8870 not responding why????????????? (MT887 is dtmf decoder) Thanks in Advance.
Friends, Anyone knows on how to control relay using dtmf (MT8870) and AT89S52 ? How can I make the circuit answer the call automatically and accept command from dtmf ? The idea is, if there's a call, the circuit will auto pickup after 3 beep and ready for a command from a remote phone, for example, numeric "1" for turning on "relay 1" (...)
I am posting this although I am able to send and receive dtmf using an MT8880 interfaced with a PIC16F1937. Althought I can communicate with the MT8880, I would like to have a better understanding of the structure of the I/O control portion of this device. After hours of experimentation, I was finally able to send and decode dtmf but the (...)
I am making a application in which I have to control the my robot using mobile phone. For that I am using a SIM300 GSM modem and standard MT8870 decoding circuit(Mentioned in the datasheet).Initially everything was working fine but after some time the speaker does not giving any output.I have tried connecting it with earphone but no response. I hav
You need an analog modulation method to transmit dtmf, e.g. AM or FM. Digital RF modules can't. It would be easy to transmit the tiny information content of dtmf signals in digital form, e.g. using a popular remote control encoder.
I am doing this ckt for my final year project. Can someone kindly share me ur working ckt diagrams or pcb. Plz help me.
rf modules and dtmf can be used. Some sort of digital circuit must be designed. First me all you need to make a truth table and then you can make a expression, and circuit.
hi, i am a student who are doing the final year project . i have done a simple light control system which remotely control via telephone. Everything function well when i do it at home , but when i want to use the telephone in the laboratory, my hardware is not function, ring detect is ok but dtmf signal cannot send to my hardware. After (...)
Hi i am a student working on a dtmf remote control device. I am using CM8870 decoder and am using a TP5089 to generate my dtmf. i am attaching the original schematic that i have found on web, but different dtmf generator chip that i am using. The transmitter side of the first schematic is being prototyped right now. So i (...)
hi everyone, i m interested in 'device control using dtmf' can anyone suggest me about this.any suggestion are heartly welcome.
check this, Home automation using phone (dtmf touch-tone)
i m developing phone and pic 16f877 application. Phone is telit 863 module. MCU can dial, answer, send or read sms. All of them ok. But my problem is, when remote phone dialing module, remote phone must be send number 1, number 2, etc. Which AT command can read this number during the calling? device 1 ---------CALL-------
My project (dtmf Teleremote control) spinning around a lot of strange problems. Every now and then it occurs and after some thought if cannot figure out, I go for Forum Thread posting. I optimize no one get bitterer by checking indistinguishable subject. But I anticipate this would be an open place to clear any doubts (basic to advanced) of a com
hello friends, i had designed 'dtmf based device control' and a sample project is here at , the problem is some of the tone are not recoginised by the dtmf decoder and it differs for each cellphone, what can be the problem and solution for the same. regards kj
I would like to make a 10 channel RF remote control to control the motion of my robotic car with a robotic arm that can perform some tasks. I'm going to use the IC UM91412B to generate dtmf, as what is posted at My problem is that I would like to make it operate
here is a data to dtmf tones dialer unit {not a decoder !!!} allows for several timing modes and full tones adjustment to reuse for other systems also can be reused as a submodel if you want to add other control logic and decoders as a unit submodel etc this unit provides squarewaves you can offset this in the usual way using a resistor an
Is there any way that I won't use microcontroller in doing this project? Yes, there is. You can use a dtmf encoder at the transmitter side and, a dtmf decoder at the receiver side. Now, you have not only the 9 freqiencies you need but also 6 extra frequencies for future improvements. Take a look at the below link: wo
hi, i have a project that about dtmf based stepper motor control via 16F877. when i pressed 4, the stepper motor turn anticlockwise. 6; turn the clockwise and 5 is stop the motor. how can i do this? anybody help me?
hie I m Tejas doing my final year and m planning to take up dtmf controlled circuit application for eg. a wireless robot or a door lock etc. First of all i m newbie and dont have exact knowledge on dis. I want to know dat will dis circuit require using two cell phones one used as a remote and the other one on the robot or will a single mobile pho
hi, i am using MT8880 which is a dtmf transceiver..after initialisation of control reg i am giving the input of 7 i want to know, how to check that wheather this IC is txansmitting dtmf signal or not thank u in advance
Zarlink ( ) has both dtmf transmitters , receivers and transceivers
hai i had made a remote control using dtmf . but how to make o/p of 8870 to 0000 on power up . it is giving jung values on power up
Please download this file
you can use a dtmf to bcd ll get a bcd output which you can interface with a ?c and do whatever you want.once i used this to interface with a mobile phone to control 4 switches of course you can control more .heres a schematic which you can connect to landline and control 4 need to dial the landline (...)
Hi, I'm looking for a schematic for interfacing telephone line to a dtmf decoder (HT9172 Holtek), in order to build a remote control activated by phone. Tkx.
Hi Can anybody tell me how to use the dtmf tranceiver IC (MT8880) over a FM Transmitter/Receiver modules i.e inputs outputs and control, data transmission/receiving using parallel port and C Language. Please help if anybody have used this IC. Thanks.
Use MT88L85 for dtmf coder/decoder and a simple FM transceiver to make wireless
Dear Friends Currently I am working on a Intruder Alarm system project with auto-dialer facility. In our system we dial the remote user during security break-up, also we are giving facility to control the system using dtmf keys from the remote side. Now we are facing some problems: (1) Initially we designed the hardware, then we wrote the s
hello friends , i am trying to make the attached circuits ,but not able to make it work. I found these circuits on a website ,does some one has other similar project or circuit ? Please help me troubleshoot these circuits . Thanks in advance !!!!
Hi, i've done a similar project on dtmf remote control system. Please inform me more details about your project. I used UMB91214 IC as dtmf code generator and 8870 as dtmf to BCD convertor for my project. MY circuit was quite similar to one shown below : (but it used KT3170)
you will have to connect the dtmf decoder to the PIC pins. Then you can input the port status. This is not very difficult. Also you can look at google, their exist plenty designs with dtmf decoder chips, maybe also with yours.
dear leilarazavi2000 what type of caller ID you have code FSK or dtmf i want dtmf simple computer program or microcontroller "8051 or pic family" THANKS S 8O KTAT
intractive voice respons system (ivrs) or any other small hobbyprojects on electronics and microcontroller based we also make projects as per your requirment