Rube Goldburg engineering challange.

[Larry Edgerton]

On the schoolhouse I am building I do not want to run a rope from the bell into the house for insulation/heat loss reasons, and I want to hook the bell up to the doorknob. It is a 20" bell. So......

Lets hear your ideas on how to make this work with a low voltage control at the door and in the kitchen so I can be called to dinner by my lovely wife. It has to be dependable so I do not have to go up into the insulated space once it is done and built with common materials.

I had a couple of ideas but I will keep them to myself for now so as not to mess with the intellectual flow......

Thanks, Larry

[Todd Burch]

What is your budget?

[John Coloccia]

I just want to understand. You want it to ring when the door opens and also when someone pushes a button somewhere, right? How far away is the kitchen to the building?

Anyhow, the house thing can be done with a button and a relay.

[Todd Burch]

He said "doorknob", but I think he meant "doorbell".

[John Coloccia]

That makes more sense. Then you could do the whole thing with a relay and two switches, and that's probably what I'd recommend because it's simple. That said, I might approach this much differently than I would actually RECOMMEND someone else doing it. If the distance isn't too far, I might consider modifying a wireless doorbell ringer to drive the bell. It would require some fiddling and actual circuitry (in other words, you couldn't do it just with wires), but it would be a pretty basic modification.

[David Weaver]

I would rip the guts out of an old garage door opener and affix something to the sprocket that would swing and hit the bell. That way, it'd be 110 v on the end where the bell is and the only battery would be in the remote activation. You could set the door adjustment on the opener to make the sprocket turn only a little bit so that it only dings a few times.

It could be complicated from the sprocket to the bell ringer, or it could be something simple like a weight on a string, something softer than the bell, like wood or plastic.

[Paul Steiner]

I am kinda working on the same problem in my classroom. I am going to use a bell to signal clean-up. Is this a swinging bell or round wall hanging bell?
A round bell is very easy to wire, just like a door bell. Find out the voltage the coil in the bell needs buy a transformer (a door bell transformer will probably work). Make a circuit and wire in a push button switch. Maybe you could find a large coil and rod to make a beefed up doorbell system.
A swinging bell would require the same circuit with a transformer, but you would a linear actuator to move the swing arm of the bell. I like this idea the best because it would give you the true sound of the bell and clacker inside the bell, instead of a hammer or rod hitting it.
If you are building a school house you can definitely figure this out.

[Matt Meiser]

Look around and see if you can find a fast acting solenoid that you could fit a plastic or wood head on to strike the bell.

[John Coloccia]

Oh...this is an actual big 'ole bell, not just a ringer. That's more interesting. Can you post a picture, Larry?

[Jamie Buxton]

To strike a big bell like that, you can either move the bell or move the striker. The traditional means would be to move the bell, while the striker hangs stationary. The easier approach for you might be to move the striker. I'd start experimenting with a striker operated by a solenoid. My first concern would be hitting the bell hard enough to produce the amount of sound you want. I have no idea how hard you have to hit the bell.

[Todd Burch]

I'm thinking a doorbell works off of 24 volts. Route a small 24v capable wire up to the bell. Near the bell, attach the 24 volt line to a contact relay for 110 volts. Have a small 110v motor with a large pulley (or affix an arm on the motor shaft) on it. Near the edge of the pulley (or end of the arm), drill a hole and mount a long bolt to it, to stick out. To this bolt, attach a rope with an eye end. Adjust the distance of the motor and length of the rope to cause momentum enough to swing the rope to pull the bell's clapper. Since the doorbell is momentary, the motor would be momentary as well, and it would be like giving the rope one quick tug. A spring attached to the long bolt and then the rope might even work better. A second rope and spring attached opposite the motor side might even be able to counteract the swing, so as to ensure only one ring per push.

Todd

[David Weaver]

I missed the size of the bell. I'd still use garage door opener parts. they're cheap, they're reliable and if you have to you can make something chain driven that reciprocates to move the bell if the bell has to move instead of the striker.

You also know that a garage door opener motor will have quite a bit of power, and be able to tolerate high and low temperatures because garages, especially unheated and uncooled can go all over the place in terms of temperature.

The parts of them that actually wear out from lifting an improperly sprung door (nylon gears, etc) will get very little wear in that application.

[Jamie Buxton]

Here's some background reading..

http://www.verdin.com/bells/bell-ringing-equipment.php

http://churchbellministry.com/

[Ryan Mooney]

Car windshield washer motor for moving the bell, possibly hooked up to an arm, not sure would have to look to rube goldberg the details.

They do come in 12v and 24v so the idea of a wireless doorbell to activate it seems plausible, but I think you might need to add a circuit to extend the "motor on" time to get it to ring nicely although you might find a bell with an extended ring time - this one claims to have it http://www.wirelessdoorbellstore.com...oot-range.html based on their comment here http://www.wirelessdoorbellstore.com/siren-12v.html wire in the washer motor instead of the siren and voila.

[Matt Meiser]

You'll need a pretty stout power source too as wiper motors have a pretty good draw. But that would work well. You could mount a wiper switch on the wall of the kitchen--slow to fast continuous ring, pull for one wipe (ring.)