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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
I have one question about sending receiving dtmf over RF modules? dtmf must be send over FM modules ?
I am doing this ckt for my final year project. Can someone kindly share me ur working ckt diagrams or pcb. Plz help me.