External power supply of 5V DC for bell/whistle controller

I would think you could use a 5 volt DC wallwart to accomplish this.

Ron

Since the power for the train has to go through the DC power supply, I don't think a wall-wart is the answer here.  You could have 3 or 4 amps, even more with lighted passenger cars.

The diode box is the way to go here.

I am missing something here John please elaborate. We are talking about a whistle and bell controller aren't we?

Ron

Correct, the current that goes to the track goes through the whistle/bell controller.  If it didn't, it couldn't put the DC bias on the track!  The way the diode box works is it has back to back diode strings to drop the AC a few volts.  When you press either the whistle or bell button, you short out all but one of the diodes, thus creating a DC bias on the track power.  This is what operates the whistle or bell.

Here's a simple box I threw together some time back, note that all I needed was SPST pushbuttons, but my junk box yielded these and they were free.  This one is wired for both whistle and bell.

Power is routed through the box using the banana jacks on each end.

Denny, in the old days Lionel did describe an arrangement for hooking a dry cell (remember those big things?) in series with the track power to operate the whistle/horn.  When the DC pulse was applied, the full AC current also flowed through the dry cell.  That is a scary thought when using today's sealed batteries that might explode!

Your efforts to just add a simple DC source in shunt somewhere will be difficult.  You might be successful if you add a series (power) resistor and inject the DC across the resistor, but the resistor must be rated for the full AC current.  Even a 1 ohm resistor will drop 10 volts when the track current is 10 amps.  A .1 ohm resistor would not drop very much voltage, but you would need to shove about 20 amps of DC through it to get an adequte DC pulse!

Your high capacity battery charger is just the ticket.  Oh, make sure that's a serious resistor, you're going to be dissipating 62 watts to get 2.5 volts across it!

Hi guys,

You are each making me rethink this approach. AsI mentioned earlier I did try a battery and was successful. I had also tried a 5V wallwart and it also worked for both bell and whistle. I asked you smart guys because I don't know if I am lucky or good. The wallwart seemed so easy that I had to ask where my thinking had gone wrong. I cross connected the DC output to the the throws of a DPDT switch and connected the poles to the AC track power. My experiment worked but I didn't know what I didn't know.

The diode string circuitry like Gunrunnerjohn shows can be made to work, but the disadvantage is that it has substantial voltage drop and heat because all of your train current is flowing through all those diodes, except when you activate the whistle or bell. I made one of those but gave up on it.  

The Lionel 147 whistle controller is really simple, and it works. I've made a whistle-and-bell controller on the same principle with ni-cad batteries (a single ni-cad for each polarity, and a center-off momentary contact SPDT switch). The AC track power goes through the battery only momentarily when you activate the whistle or bell. I thought it was weird to put AC through a battery but it is only momentary, it works, it hasn't blown up on me yet!  

This link shows how the Lionel #147 whistle controller uses a D battery. Very simple.

http://pictures.olsenstoy.com/searchcd31.htm?itm=704

The battery might work, but there's no way I put multiple amps of AC through any battery, and certainly not a ni-cad.

I don't see a large downside to the diode array except you need a bit more voltage headroom in the transformer.  I've run a conventional rig on a 4% grade with 15 or so cars and had plenty of headroom with a KW using the diode rig I posted.

Denny, what are you using to feed the track?  It might be that you have a controller that uses phase control with the output devices being OFF part of the time.  The DC from your wallwart would then be able to drive just the track during the OFF period. 

Hard to believe the track power isn't beating the tar out of that wall-wart!  I can't say that trying this ever occurred to me!

The battery method DOES work. And it's no big deal to put a brief heavy current through ni-cad batteries that were made for cordless power tools.

The diode array has to handle the full train current all the time; with about 4 volts drop that generates some heat and you need 10 heavy-duty diodes to handle typical postwar motors, up to 5+ amps with dual motors.

Photo shows my ni-cad battery whistle and bell controller, built into a plastic housing with a single-handle dual-SPDT micro-switch. I've wired two cells in parallel for each polarity. The parts were all salvage items.

Hello Dale,

I am using PW ZWs. The wallwart had a mini plug until I took a wire cutter to it. Maybe you or John would consider giving it a try. I figured nothing ventured, nothing gained!

Lionel made the #147 whistle controller on the same principle. It works OK for intermittent use. And I haven't had train speed-up or slow-down issues with it, like with my RW and LW transformers.

I would be wary of putting AC train current through a wall-wart unit.

Hi Ace,

I am wary. That is why I started this thread. Surprisingly, this wallwart doesn't seem to care. Maybe it is doing a slow burn.

AC current goes right through a battery like a wire. the probelm is the 3-4 sometimes continuouse amps MUST be carried by the battery. then there is the battery changing issue.

I like Johns diode string method. If I remember right, the diods are aways in the cicuit until the momentary NC switch or button is pushed - giving a slight boost (DC) tot he track. If this is feeding a single block and the voltage drop is an issue, you could always use another string for the other blocks eliminating the deta V going to other blocks.

I did build a diode string whistle and bell controller, it works, but with train current going through it all the time it can really heat up. I was looking at putting a mini-computer fan on it before going to the battery method. I think the diode string controller also made my trains speed up too much when the bell or whistle was activated and it was going to be extra work to fix that. And with the constant voltage drop across the diodes I sometimes had inadequate peak voltage to the track because my 110AC supply voltage is on the low side, being off-grid with inverter power from solar-charged batteries. That's fine if you want to use a diode string but for sustained use you probably need 6-amp diodes with fan or heat sinks to dissipate the heat, and sufficient peak voltage to be able to waste about 4 volts across the diodes. Just speaking from experience!

The problem I see is if your circuit is putting more than 1.5-2 volts DC to the track, you are really shortening the life of the electronic trigger in the onboard circuit boards. They were not designed to carry that much DC voltage, a volt and a half is what they were designed to operate at.

Chuck is right about the voltage. The Lionel whistle relays were made to pick up on 1.1vdc and stay picked up with only 0.5vdc. The electronic versions are presumably made to operate on similar standards. These links show the lionel whistle service info.

http://pictures.olsenstoy.com/searchcd31.htm?itm=708

http://pictures.olsenstoy.com/...hi-tend/loc-ten1.pdf

Thanks for the good feedback, Chuck.Somehow I thought it was a 5V offset. If you check the diode ladder in John's photo you will see about 4V offset from the diodes in the string. But, Ace's notice of the 147 controller supports the 1.5V theory.

In the past I built the diode ladder two ways, one where the offset added 5V and the other where it reduced by 5V. Either way I did not like the big change in train speed.

I will build a ladder with a much smaller offset and see how it performs.

Cheers

Denny

Two ways to circuit the diodes,leave them in all the time where they waste power (about 3.5 times the amperage drawn in watts) and heat up or put them in the circuit only when the whistle is blown. Doing the latter actually drops voltage by about 1.5. Doing the former gives about a 1.5 volt boost.

There is a way to have both worlds if you use a second transformer sharing a common or second transformer tap and a SPDT switch or relay contacts. For example on a PWZW using the A and B taps. Run the common contact to the track center rail. Run the A tap to the NC and the B tap to the NO run in series through the diode string 6 in one direction and one in the other direction. Set  the B tap at about 5 volts higher than A tap where you normally operate the train. When the switch or relay is thrown the diodes will be put in the circuit blowing the whistle and a voltage boost will result. 

The 1033 transformer actually has 2 taps on one throttle and could be made to do this using the A and B taps where one is 5 volts more than the other. 0-11 versus 5-16. 

The battery method is interesting but I am not sure about safety.

Dale H

K-Line had an externally powered whistle controller that does exactly what you are doing with your wall-wart.  The logic is sound, but the K-Line unit was rated a little higher than your wall wart.

You can do the same thing, but instead, use a 1033 type transformer in series with your ZW and switch it in to the circuit with your diodes for activating the sound.  If you use the 0-11 volts variable (B-U) you have the ability to fine-tune the voltage drop(or lack of, for that matter).

Something else I've done is to put two air whistles trackside, on opposite sides of the room, operable with push buttons on fixed voltage. They have slightly different tones and can be played individually or together. Fun and simple!