DTMF Decoding / MT8870
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- Опубликовано: 7 авг 2024
- This video will describe how to decode DTMF tones using the MT8870 decoder together with software running on the ATMega328p microcontroller. Other micros can be used such as the PIC on the Basic Stamp as shown in the video.
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Really really cool! Please make more videos like this one! I will build my own DTFM remote door opener.
Back in the late 70's, I built a device to control 4 VCR's for an automated CCTV channel. It used DTMF tones to control the starting, stopping. and rewinding of the machines. It was built using PLL chips to detect the tones and TTL logic to provide the various functions. It took up 4 x 6 inch perf board and at least 20 IC's. all wired wrapped. As you have shown, the whole thing could now be emulated with an Arduino Nano and the tone decoder chip.
Did the same using LM567 tone decoders to control a Ham repeater. That's all we had to work with back then.
EXACTLY what I was looking for!
THANKS!
Glad I could help!
Great video!
Thanks for the visit
Which software did you use to connect the DTMF decoder to the aurdino/How did you connect the DTMF decoder to the aurdino ??
Audacity (audio manipulation software) can generate the dtmf tones as they are built-in. If I can export the notes to to a file, then open the file and copy paste into arduino to create arrays for each key that might work to be able to make a inexpensive dtmf encoder. I started doing that but the files are kind of large like 1.6K bytes for key "1". So I am probably going to have to plot the values and remove some values to reduce the size of the code. I got pretty good quality playing back the notes back at 8KHz in Audacity. Good thing they are short ~ 0.2 second long notes. It probably has been done like this before.
Which chip did you use for your Encoder? I looked at the TP5089N but it wants a keypad with a common ground. Prefer to use a matrix keypad with only row/column pins, as that is what I have on hand.
I used the CD22859 from Harris, but I also have used MK5087 and ICM7206.
Thanks for this amazing video...
could you please make a video about interfacing this IC with a landline phone
That's what I've been trying to do for the last few days, but I think I have a problem with either the gain or the impedance
Check out this link: electronics-diy.com/electronic_schematic.php?id=971
There is also interface info in the MT8870 datasheet.
I am studying a DTMF tone assignment, I am curious how you determine the length of signal to process? ie, determine a long button press from short button press
The Data Valid (DV) output signal is active when a button is pressed and held. The digit is decoded as soon as DV is valid. While the button is held down it is in the button.release? loop. The next DTMF digit will not be decoded until the button is released and comes out of this loop waiting for the next DV signal.
Thank you so much for this video - Do you have your sketch posted anywhere? Working on a similar project.
I do not use the Arduino IDE, all my code is written in Forth with lots of examples in my videos. Enough information is presented in the video to write your own code in the language of your choice.
Cool!
Nice tutorial. I would like to detect dtmf using a microphone as an input instead. To get this more challenging for myself I will sent the generated DTMF to the Arduino over intercoms and transmit it to a speaker. Can you help me with this. Will your decoder work with a mic as input? Thank you.
Yes, you can decode DTMF tones coupled through a microphone and fed into the decoder. Ensure the audio has good signal to noise ration with little background noise. You can build your own mic pre-amp: ruclips.net/video/Qc_hngcqq7A/видео.html or get an assembled board online.
bc-robotics.com/shop/electret-microphone-amplifier-max4466-with-adjustable-gain/
What does the "crystal" do?????
I thought DTMF meant dual-tone multi-function? Anyway, thanks for this, I’ve been interested in DTMF since they are used to activate outdoor warning sirens, and I’ve always wondered about how DTMF works. Thanks!
You're welcome!
I still don't follow how you hooked up your radio to this circuit. Is this strictly for receiving and not usable for transmitting to access a DTMF repeater?
The circuit on the breadboard is a DTMF decoder receiving audio tones from a VHF receiver generated by the 5 watt VHF portable radio transmitting the tones via the keypad. The portable radio is used to access the repeater remotely.
Reminds me of 'Jackal'
Where did you find that DTMF keyboard/tone generator?
I got it from a local electronics supply store but you can also find then online. www.midians.com/specs/dtmf-encoders-decoders/tt-9
@@0033mer Thank you so much!!! Now I see a listing here w/ a price: www.ameradio.com/product/512132/description.html -> $124 .... hmmm... might be a wee bit too pricey for me. Thank you though!!!
Can you pls explain the software ??
He is using FORTH and flashforth in particular. Google flashforth.com.
Pretty much any old cell phone with a head phone jack or headset can be used as a DTMF generator.
Sorry to bother, the complete project would be:
input data from DB9 RS232, uswing module HW-044 pass the data to arduino, from arduino to BAOFENG BF-999S (only has 2.5 and 3.5 connects (NO USB no keyboard), handy 1 transmits that data in the air (I don`t care if someone else listens the data) , handy 2 receives that and pass it to another arduino and prints the data received from handy 1.
Thanks so much !!
DTMF Vegas Pro 13
Is this divorce a interference device
Great video, very didactic, 👍 Could you share the code running on Terraterm? I'm working on a similar project.
The code is written in Flashforth running on the Arduino Nano. Code starts at 4:00
@@0033mer , ah, so the tera term only shows the result that the Nano throws out so to speak?
i thought there was a program running there,
Yes.. TeraTerm is a serial terminal program that monitors the program output.
@@0033mer, quick question, is there a terminal that i could send a clickable url to, as in i send a url from the arduino, say for a google search with a search query at the end of the url,
so i send the url from the arduino and in the terminal, i should be able to click on the url so that it opens on a browser,
Check out ZOC. It has a scripting language REXX where you can do some custom programming.