Guest Kasamiko Posted February 25, 2005 Report Share Posted February 25, 2005 Hi mate..I'm planning to make a payphone out of an ordinary phone.. :oI need a timer circuit that upon triggered by a coin from a coin slot..will start a countdown timer adjustable from 3 to 10 minutes.. when time is up it will disconnect the phone from the phoneline..Any circuit..BTW:I saw a simple timer circuit using a calculator to count and some clock mechanism to count..I forgot the link.. :(rhonn Quote Link to comment Share on other sites More sharing options...
Shahriar Posted February 25, 2005 Report Share Posted February 25, 2005 Dear KasamikoHere a circuit with calculator you mean. but It didn't catch myAttention. click on " Telephone call meter using calculator & COB "here is the link http://www.electronic-circuits-diagrams.com/telephones_circuits.shtmlHTH, Shahriar Quote Link to comment Share on other sites More sharing options...
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