MT01 05SwingingSpiritBell11!22!13

Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13

Swinging Spirit Bell By Jolyon Jenkins

The spirit bell is a classic of séance magic. A small bell is caused to ring by the spirits of the dead. It can be used to answer questions (one ring for yes, two for no, etc.) and in the right atmosphere can cause real goose bumps. This one is operated by remote (radio) control and you can do it from a good distance away – even from another room, if you like. Many of the spirit bells on the market seem to me over-elaborate. There is often some huge guilty-looking sub-structure, which presumably hides something such as a lot of batteries or a giant electromagnet. And some cost hundreds of dollars. I previously published instructions for a remote control spirit bell which avoided all these difficulties. However it did have some potential drawbacks of its own, notably that you couldn’t use it in bright light or have the spectators very close, because it used invisible thread, which, in spite of its name, can be visible to those with sharp eyes. It did have the advantage of being non-magnetic and could ring a crystal bell. This version deals with those problems. Here, the bell is on a string. The two ends of the string are suspended on upright dowels. Bell, string and dowels are ungimmicked and can be examined. The base, which is 2.5cm thick, appears simply to be a block of wood. The difference is that the bell must have an iron clapper to respond to a concealed magnet.

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 How it works This time we are using magnetism, but not electromagnetism. Instead we are using a permanent magnet that moves on a remotely controlled swinging arm, and which attracts the bell, causing it to swing on the string. (I believe that this is genuinely novel as a method.) The magnet is hidden in the base, which is in fact not solid but hollowed out. It moves thanks to a rotary actuator. The actuator is controlled by a small radio control device, which you can get cheaply from E-bay.

Here is a picture of the actuator:

It’s called the NanoMuscle NM70R-2P Rotary Memory Metal Actuator and you can get it from http://store.migamotors.com. Currently it is selling for $9.95. There is also a 6P version but I have not experimented with that. The way it works is that when 6V volts is applied to the two terminals, the shaft rotates about 45 degrees. When it reaches the end of its travel, or when the voltage is removed, it springs back to the start. If you keep the voltage applied, it will oscillate back and forth. It is not very strong, but it is very light at 4.2 grams, silent, and thin. This makes it better than a motor for this application. The radio remote control is supplied by an off the shelf unit operating at a frequency of 433MHz. Here is a picture of it together with the key fob that controls it.

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At the time of writing there are several E-bay sellers offering this unit, for less than $10. For example http://www.ebay.co.uk/itm/433MHZ-4-Channel-RF-Radio-Wireless-ControllerRemote-/320516889412?pt=UK_Gadgets&hash=item4aa04b9b44#ht_5601wt_952 By the time you read this, that listing will probably have gone but search on 433MHz and you should find another. In a previous project (the self-lighting candle) I suggested using a radio control unit that incorporated a relay. This one does not have a relay but it is much thinner, which is what I think we need here. You will need a relay but you can choose one that is much quieter than the ones incorporated in the integrated units. Of course you will need a bell. It has to be ferrous to attract a magnet. These are harder to find than you might think but I have discovered that they are available on Ebay and the thing to search for is “string of bells”. Sometimes they are called temple bells. Here is a set of bells of different sizes:

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You can get this from http://www.shamaniclifestyle.com

Those bells are advertised as solid brass but in fact they are impure brass and contain some iron. The clappers however, are iron and so will serve our purpose. I have also seen strings of bells for sale in new age/witchcraft/hippy shops; sometimes they look like miniature cowbells which is not my taste but might be yours. You will need a magnet. It’s a rare earth (neodymium) magnet, much stronger than traditional magnets. The one I used is 20mm in diameter, and 3mm thick. You can find these for less than $1 each on E-bay. You’ll need a reed relay operating on 6V – you can get this from electronic suppliers like Radio Shack (in the US) or Maplin (in the UK). I have made a small modification to the electronics compared to the previous version. I discovered that some of the remote control units don’t like being driven from the same power supply as the actuator. To deal with this I’ve put them on separate circuits. So you’ll need a small 6V battery, code 4LR44. This drives the remote control receiver. The actuator is driven by 4 AAA batteries. You will also need a holder for these. In the previous version I did without the holder to reduce thickness but I do not now think it is worth the trouble. You will need a tilt switch. This is to enable you to switch the entire thing on and off without having a visible switch on the outside of the unit. The receiver will be on and ready to receive when the unit is the right way up, and it will be off when it’s upside down (e.g. when stored). This will stop the batteries draining. You’ll need some construction wire. Everything else is available from your local hardware store.

Construction We start with the woodwork. I used a piece of oak here. You could use softwood but we want the magnet to be as close to the top of the unit (and so as close to the bell) as possible. With a hardwood like oak you can work to finer tolerances and cut the top of the unit thinner.

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 I used a piece of lumber about 20.5 cm x 7 cm x 2.5 cm – these are final dimensions once the surfaces are planed flat, the edges straight, and the corners square. You need to effectively hollow out this piece of wood. This is easily done with a router but if you don’t have one you can use a chisel and hammer – it will just be a bit slower. The hole you need to cut must be 5.5 cm x 24 cm x 2 cm deep. (Note that this will leave the top of the unit 5mm thick – if you are brave and confident in your woodworking skills you could reduce this to 1 or 2mm) Also cut a hole for the little battery to go in. This should be 3.3cm long x 1.7cm deep x 1cm wide. You also need a small hole for the tilt switch.

Now cut a rabbet (i.e. a groove open on one side) round the outside of the hole you have cut, 3mm deep and 3mm wide. The lid of the unit (on the underside) will fit into this recess. You will also need to chisel/rout away the material at the end around the small battery and tilt switch.

You should now have something that looks like this:

Now cut the bottom: it needs to be 3mm thick and fit snugly into the recess. You could cut it from the larger piece, if the larger piece is thick enough. I used a band saw to cut off a slice. The base is simply wedged into the rebate and held there by friction. It will never be seen by the spectator anyway.

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If you have difficulty holding on the bottom by friction, you can use sticky craft glue dots to do the job, or tiny magnets. Here is the bottom, fitted into the unit

Now on the other side of the unit you need to drill two holes to accept the dowels. If you want nice clean holes with no ragged edges, use a Forstner bit. Obviously the holes must be the same diameter as your dowels, and the holes must be on a part of the unit where you don’t have a recess underneath. Cut two dowels of about 20 cm. Drill a hole (or a slot) in one end of each dowel for the string.

The Electronics. Start with the 4LR44 battery. This is going to go in the slot that you cut for it, and we need to make the contacts for it. The positive contact I made from a thin strip of brass. Or you could use the head of a nail. Solder a piece of red wire to the brass, and then glue the strip into place using a hot glue gun. The negative contact is a spring. You can buy these from electronics suppliers or cannibalise another battery holder (which is cheaper). Solder a black wire to the spring and then glue it in place. The battery should now fit snugly in the slot, held in place with the spring.

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 The red wire will go to one terminal of the tilt switch. The other terminal of the tilt switch will go to the receiver. But for now, short out the tilt switch because you want everything working whichever way up the unit goes. We turn now to the power supply for the actuator. Solder a pair of red/black wires to the battery holder for the 4 AAA batteries, and glue the holder in place at the far end of the unit. Now for the actuator. You need to shorten the shaft. Cut off all but about 2.5mm using a junior hacksaw or Dremel power tool. Do this carefully because the actuator is not very robust. Solder a pair of wires to the two terminals on the actuator. It matters which way round these go. To make matters worse, the data sheet originally published by the manufacturers was wrong, and there are some incorrect versions still around. To be clear, the positive terminal is the one furthest from the rotating shaft. Solder a red wire to this, and a black wire to the other one. Now you need to make a rotating arm to fit to what remains of the shaft. This is made from a thin strip of steel or brass. I actually used part of an old music stand but I am sure you can find something in the hardware store. It has to be rigid, and thin. It’s 5cm long and about 8mm wide. Drill a 2.5mm hole in one end of the arm, about 5mm from the end. Glue the magnet to the other end. It should be slightly offset, like this

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Push the shaft of the actuator through the hole you drilled in the arm, and secure using superglue. The arm and actuator should be parallel to each other, with the magnet on top. Here is a side view

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 Make sure you don’t glue the shaft to the body of the actuator, thus preventing it from operating. Now for the receiver. Refer to the picture of the unit that I showed earlier. You will see pins sticking out of the right hand side. Starting at the top, the first pin (we’ll call it pin 1) takes the positive power supply voltage. The third one takes the negative supply. The bottom four are output pins. Since there are actually four channels on this remote, you could use any one of them, but if you choose to use channel A then the output pin you need is the bottom one. The pins are too long so you will have to shorten them with wire cutters. Here is a circuit diagram. As you’ll see, it’s very simple:

Correction: 4/22/12 - Customer Doug Ries noticed that the numbers 3 and 7 in the diagram were switched in the original e-Book. In this version's diagram, they are in the correct position.

A word about the relay. It has to be a reed relay, because they are quiet, and because they will run directly on the output from the unit. I got this one from Maplin. http://www.maplin.co.uk/dil-reed-relay-2613

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You could also use this one from Maplin (order code JH12):

Radio Shack has pretty much the same thing: http://www.radioshack.com/product/index.jsp?productId=2062478

With such a simple circuit you don’t need a circuit board; you can just solder everything in place and secure it to the wood with a dab of hot glue (be careful not to let anything get too hot or you could damage it). The actuator and arm have to be attached to the unit so that the magnet swings close to the inside top of the unit without actually touching it. It will have to be glued by its edge to the inside edge of the unit – because you may not get the positioning right first time, use hot glue rather than superglue, so you can go back if you make a mistake. Here is the unit with the components in:

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You may find that the when the arm swings back, it knocks into the wood making a clunky noise. You can deal with this by gluing a piece of sponge to the magnet or the timber. So that’s about it. When the actuator is moving properly in response to the keyfob, unshort the tilt switch. You will have to experiment with the right length of the string. I found that I could get the bell to swing convincingly when hanging about 15mm above the base. When in use make sure the surface of the unit is free from any dust because any small quantities of iron filings there will give the game away, by moving around with the magnet.

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The keyfob If you have an accomplice in the audience, you can get them to operate the bell using the keyfob inside their pocket. But if you are on your own you need a way to press the button secretly. The classic way is with a toe switch. In this case the keyfob is small enough to fit inside your shoe so you can press button A with your toe. Just secure it to your foot with a piece of sticking plaster so your toe stays in the right place. If you don’t want the keyfob in your shoe, you can use a separate switch. The fob dismantles easily with a jeweller’s screwdriver. Here’s what it looks like inside:

You’ll see that the four buttons push onto microswitches. On the other side:

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Each microswitch has four contacts but you’ll see that only two of them are actually soldered. This makes it comparatively simple to unsolder them. You can then attach a pair of wires to the points on the circuit board and relocate the switch at a distance. So the keyfob could be in your socket and the switch under your toe, which would be more comfortable. You can glue the switch to an insole of the kind you can put in shoes to make them more comfortable. Or just a piece of plastic cut to the right shape from a bottle. Don’t want to use a toe switch? Here’s another idea. Use a reed switch. These are tiny switches that are operated by a magnet. (I use one in the falling desk frame project.) You could have the switch inside your jacket (with wires running to the keyfob). The magnet could be inside a thumb tip. When you are ready, slip on the thumb tip, and to operate the bell just bring your thumb next to the switch. You could experiment further with placing the switch on one part of your body (eg your side) and the magnet

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 on another (eg your arm). But the thumb tip will work and means you don’t need to be wired with a toe switch all the way through your act.

In performance The good thing about this is that you can hand out the bell, the string and the dowels for inspection. Obviously you can’t hand out the base unit itself for inspection but it also just looks like a bit of wood. You could even get the spectators to assemble the bell themselves, so long as you keep hold of the base unit. The Spirit Bell is not just for séances. A Christmas bell (or a jingle sleigh bell) can be used as a test to find out who’s been “naughty or nice.” Or it might signal when a gift arrives in a Santa Bag (egg bag) or chimney (magic box). Any kind of bell can be used to locate a chosen card – regular playing card, Tarot card, or for children, a picture card. There are many card effects in the literature in which a card is secretly chosen and then revealed, but the person who reveals the card is usually the magician. The Spirit Bell makes it possible for the revelation to come from an invisible spirit who locates the card by ringing the bell when the chosen card is pointed out by a spectator. Here’s a Christmas trick that uses a jingle bell on a ribbon as the “Spirit Bell” and a pack of cards with pictures of various seasonal pictures: a candy cane, a wreath, a Christmas tree, a reindeer, an elf, and a stocking filled with gifts (just to make sixyou can add others and change the designs for any occasion). Imagine that you have painted the key fob remote unit flesh tones (or wrapped it in flesh tone bandages, or hidden it beneath a Sanada gimmick). You can easily palm the flesh tone hued remote when you pick up the cards (especially if they are jumbo sized cards) and keep it hidden beneath the cards or beneath the card box used to hold the cards. If the backs of the cards are distinctively marked, you can tell the design on the face by simply looking at the back. Have the six cards shuffled and placed in a circle around the bell while your back is turned. Have someone randomly select one of the face down cards and draw it out of the circle. Turn around just as they do so and tell them that you want them to pick the card up and show everyone in the audience the design on the face of the card, but wait until your back is turned again. You already know what the design is from having seen the back of the card that was about to be picked up, but throw them off the scent by telling the person who is showing the chosen card to pick up all the cards and shuffle them so that no one, even the person who chose the card, knows where the card is. You then turn around and ask the bell if the card was (for example) a candy cane. The bell is silent, so you continue asking about the designs until the bell jingles. Now you can have a spectator point to the cards one by one and the bell will jingle a second time when the person is pointing to the correct design. I am sure others will come up with even more creative and mystifying ways to use the Spirit Bell in magic.

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 Addendum 4/22/12: Customer Doug Ries, of Flip Disc Productions (www.FlipDisc.com) also wrote: I’ve made an improvement to the bell. Instead of using a bell attracted by magnetism, I used a pewter bell, which is not magnetic. I cut the tip of the clacker off and superglued a small bar magnet in its place. Orient the magnet to repel the magnet in the base. This will give the bell better action and cause it to ring better. I found the bell on ebay. http://www.ebay.com/itm/Ghost-Rider-Spirit-MotorcycleGuardian-Bell-Pewter-NEW/380429717233?pt=Motorcycles_Parts_Accessories&hash=item589360cef1&vxp=mt r I like the look of these (Guardian) bells and can tie in the story of the bell. They are used by motorcycle riders and hung on the bottom of the bike to keep evil spirits away. I’m going to use this in my script.

I’ve attached some photos of my version. With the bell modifications it doesn’t matter if the bell is off-center of the magnet because it only affects the clacker and with the magnet poles repelling gives the bell great motion even when off-center.

I don’t mind sharing creativity. It makes our art stronger. Doug Ries Page 15


Appendix (added 11/22/13) After I made the original unit, I carried on making some improvements and alterations, and the updated version is shown below:

As you see, I decided to stain and varnish the unit to give it a more antique look. I also found that since the positioning of the bell over the magnet is quite critical, it would be better to have a more precise and fixed positioning. So I replaced the string with a chain, and the wooden uprights with brass ones. The brass uprights have threads at the end, which screw into threaded brass inserts sunk into the wood. I cut a notch in the top ends of the uprights and attached glass beads to the end of the chain, so the bell is now permanently threaded on the chain. This allows for a quicker set up. If you are going to do this, don't cut the notches in the brass until you have screwed the posts into the inserts, so you know exactly how to orientate the notches. Also, make sure when positioning the posts that the bell will hang directly over the magnet when it's in its resting position. Otherwise you risk the clapper hanging askew and looking somewhat odd. After I made the original unit, I carried on making experimental changes to the circuitry. Something I came to appreciate is that the remote units come in different varieties. They all look the same but some of them have a “momentary” operation, some “toggle”, and some “latch”. Momentary means that it operates only while the keyfob button is pressed. Toggle means that it comes on when the button is pressed and goes off when it's pressed a second time. Latch means it comes on when the button is pressed and stays on until power is removed. The spirit bell will work with momentary and toggle, but momentary is better. You can tell which sort you have got (or are buying) from the writing on the chip: They all have SC2272 but momentary has the suffix -M4, toggle is -T4, and latch is -L4.

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 A good source for them is here: http://www.adafruit.com/products/1096 or if you are in the UK, here: http://www.hobbytronics.co.uk/rf-receiver4-mom Confusingly, the pictures on these websites show the toggle version although they are advertising momentary. If you buy from them you will also need to get the keyfob unit separately, which makes it slightly more expensive than the Ebay versions but the advantage is they don't come from China. Note also the pin-outs here are different from the original one I used: the pin marked VT is where the positive red wire from the battery goes, GND is for the black negative wire, and D0 is the wire that goes to the relay. However, I also experimented with eliminating the relay, and you may prefer to do this. I used a MOSFET1 transistor in its place. The one I used was a Stp36nf06l – Google this and you will find suppliers. As it happens, this Mosfet is considerably over-specified for the job, and you could probably use a much lower power one, and save yourself a few cents/pence but I do happen to know that this one works. If you want to experiment, any “logic level N-channel Mosfet” will probably do. You also need a 100k resistor. I also found that with this modification, I could use the same battery to power both the actuator and the receiver. This is a big advantage because the little batteries tend to run down fairly fast, particularly if you forget to turn the unit off. The wiring diagram for the new arrangement is below. There are three terminals on a Mosfet, called Gate, Drain and Source. On the one I used, G D and S are arranged left to right in that order – others may vary and you'll have to check the datasheet.

Note that I have specified the pins on the receiver as per the original version – if you use the one from the websites given above, they will be different.

1

The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a transistor used for amplifying or switching electronic signals. You don’t need to know any more than this, but look it up on Google if you feel you need to know more.

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Magi-tronics Book01-05 Swinging Spirit Bell by Jolyon Jenkins – addendum 11/22/13 Credits: Traditionally, the Spirit Bell was a spiritualist's effect in which a bell, isolated under a glass dome, rings “yes” or “no” answers to questions. Adopted by magicians, it was performed as early as October 1852 by Canadian magician Prof. Gurnet in Boston, Massachusetts, as reported in a Boston Bee advertisement in which it was referred to as the “Spirit Rapping Bell." The earliest Spirit Bells sold in magic stores were operated by spring wound clockworks and were timed much like a mechanical music box.

. © 2013, www.magicnook.com and Jolyon Jenkins All manufacturing rights reserved. The purchase of this e-book entitles you to construct one item for your own personal use. If you are interested in acquiring a manufacturing licence please contact the author via the Magic Nook ( [email protected] ). Copying and resale of this ebook is prohibited by International Copyright law.

Jolyon Jenkins is a journalist who published his first article in “Everyday Electronics” at the age of 16 and went on to write for a number of electronics magazines before drifting into a job as a radio producer and presenter. As an amateur magician, he performs as Montague The Mysterious, and has made a number of radio documentaries about magic including one about the centenary of the Magic Circle, and another about magic busking. He has two children who are bored with all his tricks but who are occasionally infuriated by new ones.

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MT01 05SwingingSpiritBell11!22!13

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