BS-1 IC for DTMF Generation
Dave-W
Posts: 94
Hello All,
Due to cost and size of the BS-2IC I want to use the BS-1 to generat DTMF tones for a phone dialer. I only need 9 numbers using a zero to nine keypad. This should be easy but I am at a loss on how to·get a good·start. Using a DTMF chip would indeed add money to this project that I am helping a high school student getting this to work. I have searched the archives with no help at all. Someone must have done this before. I just need a little nuge in the right direction.. The keypad input is already done. A last resort is using a DTMF generator IC. But it has to be low cost and easy to connect with few I/O pin(s). And still available. It seems that all I have tried to get have been discontinued, costly and not easily available.
I have tried to use two 555 timer chips but the frequency is not dependable and requires too many I/O pins.
Thanks guys and girls for any help or directions that will have results.
Dave
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Dave W.
Due to cost and size of the BS-2IC I want to use the BS-1 to generat DTMF tones for a phone dialer. I only need 9 numbers using a zero to nine keypad. This should be easy but I am at a loss on how to·get a good·start. Using a DTMF chip would indeed add money to this project that I am helping a high school student getting this to work. I have searched the archives with no help at all. Someone must have done this before. I just need a little nuge in the right direction.. The keypad input is already done. A last resort is using a DTMF generator IC. But it has to be low cost and easy to connect with few I/O pin(s). And still available. It seems that all I have tried to get have been discontinued, costly and not easily available.
I have tried to use two 555 timer chips but the frequency is not dependable and requires too many I/O pins.
Thanks guys and girls for any help or directions that will have results.
Dave
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Dave W.
Comments
Some that I found on a simple websearch:
www.npcamerica.com/pdf/SM8230.pdf
www.nteinc.com/specs/1600to1699/pdf/nte1690.pdf
The NTE part seems to be available for about $8
blog.makezine.com/archive/2008/06/how_to_make_a_dtmf_phone.html
Do remember that a BS2 has a built-in DTMF dial tone generator statement. The OEM version is large, but only $31. The BS2 module is $50, but is sometimes on sale cheaper and can do the whole job using no other parts (other than the keypad and audio output parts).
Post Edited (Mike Green) : 7/29/2009 4:01:39 AM GMT