I am trying to convert an old rotary phone into a timer used by my kids. Most of the project is already done and working - the timer can be set with the rotary dial, it fires off correctly etc. I have also set it up for battery operation - the Arduino is turned on if the piece is taken off the hook.
What I have problem with are the bells - I hoped that I could use the original ringing mechanism. However, I realize that it was designed for circuits with more voltage - obviously I would like to avoid that for a DIY batter device operated by kids. For now I have just connected the electromagnet to two pins and I am switching the signals - the hammer oscillates, but it does not have enough force to strike the bells to produce decent sound.
I have thought of a 9V battery and relays, but then I am not sure how to reverse the current. I have also considered a servo with a metal piece, but I do not know whether it will be strong enough to produce sound...
Any other ideas?