Novice looking for help with a fun/goofy idea.

[garloo]

Hi,
I'll make this brief, maybe someone can tell me if this is doable.

I have this old telegraph receiver. This is the end where the "click, click, click" came out. Its basically two coils of wire (electro magnets) under a bar. What I would like to do is...., are you ready for this.. I would like to connect it to my landline (yes, I still have one). In the not too distant past we had phones with bells connected to the landline. So I suspect there is enough power to toggle the clacker thingy... But I don't want to mess up the phone line. Would there be a way to make something that would take the signal from a regular landline (24vdc?) and convert it such that the clacker would go up and down (instead of ringing the phone)? I figure this could be hooked into any phone outlet and my regular phone would still ring while this thing would click-clack away...

It would make a great-functional conversation peice.

Thanks!

[pebe]

Yes, it's do-able. There is normally a DC voltage on the line, sent from the exchange. When a phone is being called an AC signal of about 75V to 90V AC is also sent from the exchange.

You can see a couple of circuits here (about half way down the page ) that sense the AC voltage and use an opto-coupler to give an isolated switch that switches on when ringing is taking place.
http://www.epanorama.net/circuits/telephone_ringer.html
You could then use that switch to turn on a relay to actuate your clacker.