sensor choice for "gong detect"? & invisible light switches

If it were me ........... I'd use the "Clapper"

They're coming to get you....

dunno abt the bell thing...maybe if you analyized the frequencies generated by that particular bell you might be able to build something. Sounds like a big project though.

density sensor...try hollowing out the back of the dry gypsum material so that you just have the front paper left and hot glue your sensor in from behind. you may be able to get the front paper sheet thin enough where it will work.

I haven't tried this but it might just work. Install a magnetic switch just near enough to the electromagnet that drives the bell that it trips when power is applied. You may have to experiment a bit to get it right.

for your invisible light switch why couldn't you just put a pressure sensor, ala the type used under floors, on one side of the sheet rock?

for a reliable invisible light switch you can always go to centralized lighting like centralite or crestron.

For the "touch" switch, you'll usually find in some basic hobby electronic books, Capacitive switches. These are the devices that you'll find in table lamps that turn on and off by touching the metal portion of the lamp. There are also some wall switches that will do the same thing with the addition of dimming or brightning by holding your finger to the metal surface of the switch. With the hobby switch circuitry, if you experiment a little, you can change some component values that will allow you to simply pass your hand near the sensor rather than having to touch it. This way you could bury it in the wall but not have to actually touch the wall to activate it. You'd have to interface the output to a relay to operate the lights.

As far as the bell goes, a simple old fashioned vibration sensor should do the trick. The Ademco # 11 vibration sensor is still avaiable or any similar unit should do it. They're adjustable so you can set it to what ever it takes to cause it to trip. Of course, you'd have to provide the relay and power circuit to utilize the output.

But ..... in a pinch ........ don't forget about the Clapper :->

The old Window Bug sensor might work. It is adjustable. Check out below:

Does the bell tip much to ring? If so you could use a mercury motion switch on the inside.

Also, if you could electrically insulate the clapper the you could set up a circuit that would be completed when the clapper hit the inside of the metal bell.

BobbyD

Tracker wrote:

Take a couple of pictures of the bell itself and post it to a web page we can all reference. It would be far easier to suggest a solution if we could have a look at what you are dealing with here.

I've seen some pretty sophisticated looking touch control dimmer switches at Home Depot the other day. I'd stick with a solution that wouldn't involve anything to "esoteric" if I were you (both from service and "end-user" standpoints)

| > Anybody ever *actually done* a sensor on a heavy bell? (It's a | > large-size "Mission Bell" by Tom Torrens, if you care... To be used as | > a doorbell, well, actually as a button replacement for a DSC door box.) | > Specifically triggered by the resonating from the gong itself, no | > stuff like mallet switchhooks or motion sensor on the swinging mount... | > I thought about an old-style glass break, but getting the frequency | > right would be a trick. | | Take a couple of pictures of the bell itself and post it to a web page we | can all reference. It would be far easier to suggest a solution if we could | have a look at what you are dealing with here. | | | >

| > Also does anybody know if commercially cheap density sensors can be | > used to determine if a finger is placed on the other side of sheetrock? | > I'm gonna go do some experiments, so don't shoot me for asking first. | > But if someone has *already* done it, please let me know. Why did this | > come up? Well, I was looking at a Leviton "Acenti" ad the other day, | > and thought, "Why on earth does anybody want a larger, more prominent | > light switch?!" Remember the Pass&Seymour/Legrand ones? Ugly. as. | > sin. Anyway, shouting "lights" at some comput er is silly, and motion | > sensors don't have the positive control (or on-location dimming) | > needed. Again, don't flame me about greasy spots on the wall, or | > repairability of buried switches -- just, *if* you've done it, pretty | > please tell me what you learned. | >

| > Thanks in advance! | | | I've seen some pretty sophisticated looking touch control dimmer switches at | Home Depot the other day. I'd stick with a solution that wouldn't involve | anything to "esoteric" if I were you (both from service and "end-user" | standpoints) | |

An audio control relay might work. Try University Sound ACR-1. Would not be my first choice, but that's the only thing off hand I can think of that would do it. Problem is unless you are very careful with your microphone and layout you may get false triggers from other sound sources.

I think a AC contacter of some kind triggered directly from the bell current might also work. Radio Shack used to sell some labeled as AC relays, but I haven't seen one in a while.