ringing phone

I'm currently in progress on connecting an old phone to an arduino. I'm managed to get the dial and audio portions working but the part that keeps eluding me is how to make the bell ring. There doesn't seem to be any noncomplicated solution documented out there. The standard reference everybody is given is the sparkfun ringer from back in 2005 which involves sourcing a lot of possibly out of production parts and soldering. The explanation and diagrams provided also are not elaborated enough for someone like me to work with and how to interface it with the arduino is an additional thing I'd have to hash out myself.

I was wondering if there was an simpler 'drop in' solution I can use. A purchaseable board that can be triggered to convert arduino 3.3V or so to whatever Voltage and hertz necessary to drive the phone bell. (the references say its 90V AC overlaid on 48V DC at 20HZ)

I've come across pictures that seem to be doing just that

This guy appears to be driving a phone bell without even boosting the voltage to anywhere near what you are supposed to or even converting it to AC with simply a single prefabricated board. Unfortunately I haven't yet gotten in contact with him. Any suggestions? I really want to be careful not to destroy what I have with a mistake.

The bell itself only needs AC at around 90V
The referance to 48V DC was that phones traditionally were fed from a 48 V battery in the telephone exchange so there was
always 48 V on the line when the phone was on the hook.
To make the bell ring, 90 V AC was superimposed on the 48 V DC, but the bell only got to see the AC as they had capacitors in series with them.
Depending on how loudly you want the bell to ring, you could try much lower voltages than the 90 V.
You will however need some way of generating the low frequency AC voltage for the bell.
A simpler solution would be to junk the bell altogether and use a low voltage DC buzzer which an Arduino can easily drive
with a simple transistor switch.

12 V DC to 110 AC car's inverter? Probably you can find one for less than 20$. Step up DC-DC 3.3 - 5 or 3.3 - 12 also shouldn't be a problem.
You also may build inverter with arduino:
http://www.kerrywong.com/2010/03/12/a-power-inverter-with-arduino-pulse-source/

The 80 volts is to ensure the bell rings at the end of a long line which may have a resistance of a few hundred ohms. Something like 25 to 40 volts may be more practical.

The situation is the very reverse of a switchmode power supply, to transform say, 12V to the necessary voltage at this low frequency would require a quite large transformer - about three times the size required at 60 Hz. On the other hand, the current requirement is quite low, so not so big a transformer but you would have to de-rate the voltage specifications of a standard mains transformer to a third. In other words, a nominal 110V to 12V transformer could be driven backwards from 4V AC to generate 35V or so.

The alternative is to generate 35V efficiently using a switchmode converter, and convert that to AC. In either case, you generate the AC using an "H-bridge" rated for the voltage in question. The bell will not care that it is fed with a square wave instead of a sine wave - in fact, it may respond to a slightly lower voltage.

The pictures you cite seem erroneous in not demonstrating any useful method of converting the DC to AC to operate the bell. You can't believe everything you see on the 'net!

You do need AC to make the bell ring, however it should work with only 5 or 10 volts. The high voltages are used because of the very long distances between the exchange and the subscriber.

Mark

Yes, just about anything from about 10 to 60V AC will work.
Just make sure that what ever is supplying the voltage has enough current.

I'm going to use this voltage booster which supposedly outputs 12V 100mA

to drive this ring generator

to ring the bell. Will everything work together? I want to avoid damage to any of the components.

I think you are going to need to hook up that ringing generator to a 12V power supply and measure the current it draws - connected to the bell - first.

I suspect 100 mA is not going to be sufficient. (It is apparently an "orphan" product - virtually no information on the internet, but somewhere it is quoted at 3 Watts output, which is substantially more than 100 mA at 12V.)