Building a Whistle/Bell Controller

[philo426]

I built the sound activation button according to the instructions found in the NOV '98 issue of CTT.The article is very thorough and gives you a complete Radio Shack parts list.I built it and it works just fine.You just have to carefully follow the wiring diagram and it should come out ok.

[Anonymous]

BTW

The circuit will work with less diodes, 5 pair and jumping 4,or even 4 pair and jumping 3 on some engines. The extra diodes are to get some extra voltage to compensate for an air whistle. The newer solid state electronic engines are less demanding. You will have to experiment to see what works best on your layout.. You can get 6 amp diodes on ebay for about 25 cents each. If you are handy at soldering you can solder them together. The diodes will get warm under operating conditions but not hot.

Dale Hz

[Anonymous]

The voltage drop will be 4.2 volts AC,each diode blocks only half the sine wave. Transformers start at about 6.5 volts ,so about 2 volts gets to the track. You may have to move up the throttle a bit to engage the reverse unit. Modern reverse units need less voltage than the old PW E units . When the whistle is blown there is actually a slight boost in voltage.

Dale Hz

[BobbyDing]

(this post edited to correct some numbers. Thanks Dale Hz)

OK, I think I understand this. I'm not very good at AC stuff, so anybody please jump rite in and correct me if I'm off.

Oh, also I think I must state the usual PC warning that mucking with your system like this can cause perminent damage! If your not sure about it, go buy a proper controller. I don't have any expensive electronics on my layout (all convensional), so there is room for playing. I don't want my rantings to cause somebody to destroy their valuable (or even cheap) equipment.

So,

Each diode has about 3/4 Volt drop across it. So when connected as described above (Daisy chain two seperate groups of six diodes each, all 6 diodes in each group facing the same direction. Now attach the two groups of six at the ends only, with each group facing the opposite direction of the other. One end goes to the xformer, one to the track).
This should cause ~4.5 volt drop in total AC voltage (~4.5V in each direction lost across the diodes) to the center rail. When 5 of the diodes are jumped , the AC wave will shift higher or lower because the voltage drop will now be smaller for the group of diodes you've jumped, causing a DC offset and triggering a bell/whistle. Visa-versa when alternatelty jumpering the other set of five diodes. You jump only five so that the last diode keeps you from shorting out in both directions.

So this setup will subtract about ~4.5 volts from the track voltage and add back about ~4 volts DC in either direction when triggered (jumped), thus triggering a sound. Does this sound correct?

I wonder if there is a simple toggle switch configuration that could be wired that leaves full VAC to the track. But when switched to either side (momentarely) it would switch in either set of series diodes (plus jumper and the one extra diode)? So you only loose 4 volts when you trigger a sound and have full track voltage all the rest of the time. Just wondering. I suppose that if it could be done it would have been done by somebody hear long ago.

I'll have to pick up some larger amperage diodes this weekend and play. I only have 1 amp diodes in the parts bin rite now. Has anybody else tried this diode configuration?

Bobby

[cnjcomp]

Okay, My reasons for wanting to build my own are twofold. 1. I like to tinker and learn new things. 2. I am building three layouts one triple loop at my house and two double loops one each at my Granchildren's houses, so I need 14 buttons (2 for each loop).

Here is the original text posted by DaleH Z:
Posted by Dale Hz

Burns electronics and others makes a good whistle activator or you can build your own,using 12 diodes and a barrier strip. You will also need a relay to activate the circuit from the insulated rail. To make your own controller,string 12, 3 or 6 amp diodes,6 in each direction mounted in a 12 position European style barrier strip. Connect the 2 ends and wire them in series with the center transformer tap. Jumping 5 diodes on one side will activate the whistle while jumping 5 on the otherside will activate the bell.

Thanks for the help.

[BobbyDing]

I have to agree that buying one is probably your best bet since I don't think they're very expensive. Unless your like me (ametuer tinkerer) and you want to try doing it yourself first.

Just tonight I replaced the whistle relay with an electronic one basically copying Lionels that is in the Polar Express tender. It used an R/C filter to remove the AC, and lets the DC thru to turn on a transistor that runs the small DC motor for the whistle. I added a triac to the output stage to run my post war AC whistle motor (couldn't stand the chattering relay anymore). So far it turns on a light bulb when the whistle lever is engaged. Tomorrow I'll hook it to the whistle motor and see if it works in the real world.

I would be interested in the diode assembly your refering to for a controller. Can you post the text? Maybe somebody here can make some sense of it.

Bobby

[Anonymous]

Brought up an old post concerning transformer advice. There are links to other posts in it describing the whistle controller.

Dale Hz

[phillyreading]

cnjcomp, welcome to the forum.
I have tried to build the same whistle/bell controller that I think you are talking about from an older CTT magazine article and for all it is worth BUY IT NEW!!!! I never could get it to do what the article described, also I have decent knowledge of residential/industrial electrical work and automotive wiring and I can not get the controller to work as described in CTT magazine.
Lee F.

[Jumijo]

Why don't you just buy one?

Jim

[cnjcomp]

Help, I'm stupid. I've read the string on using 12 diodes, a European buss,
wiring in parallel in opposite directions with a relay, but this is all Greek to me.
Does anyone have a copy of the original CTT article on building one of these?
Thanks. By the way, I've enjoyed viewing the forum, and find you folks to be very knowledagble and very helpful .