Ring that bell!

[chessageed]

Hi,
This is my first post and I'm new to arduino in general - bit of a lockdown project.

I'm restoring an old rotary telephone from the 1960s which has a bell as its ringer. For those of you who havent seen one it looks like a metronome on its back with a bell on either side. When the phone rings he spindle with the spindle with a ball on the end vibrates back and forward striking each bell causing that harrowing old phone sound.

The bell works off the AC that comes through the phone wire I believe and as such it appears to have 2 electromagnets on either side of a spindle which is attached to the ringer; so it uses the frequency / AC to turn on one magnet, then the opposite one and back again etc etc.

I've managed to make it do one ring by putting a voltage through one of the magnets but now I'm stuck as to the best way forward of how to make it ring.

My thoughts were (aside from asking for help) there would be 2 main ways of achieving this - either make the electromagnets turn on and off through the magic of an arduino / coding OR put a motor between the bells and make it go back and forward striking the bells directly.

I'm sure there are better ideas out there as I'm very very new to this.

Thanks in advance for your help,
AJ

[jremington]

You need around 80VAC at 20 Hz to ring an old-style U.S. phone. A rotary phone conversion project is described here: Port-O-Rotary - SparkFun Electronics, ringer circuit here, or google "rotary phone ringer circuit" for other examples.

[gilshultz]

In place of typing several pages of information use this link: http://oldphoneguy.net/images/oldtex22bw.pdf It is called http://oldphoneguy.net/images/oldtex22bw.pdf written by the oldphoneguy, it is great! As far as the ring the phone impedance was 600 Ohms, the ring was AC 20Hz about 100V, depending on how far you were from the CO as stated previously. The phone circuit is a 4 wire system which is transformed to two wire in your phone with that thing with all the screws called a network.