In tech specs at Tonys train exchange someone wanted to do the same thing. This is the response. " The DCC Specialties Block Watcher will do exactly what you want. It will detect current and turn a switch on. The switch is completely isolated and will switch AC, DC, or DCC and is good for up to 30 volts and 1 ampere. You can also calibrate the trip current level so it only responds to the actual movement of the turntable."
Hope this helps,
Philip
mkepler954I posed the question of compatibility to to ITT and this was his response- I have not seen any turntables out there that have provisions for my sound modules. Others have asked me about the Walthers too. It has been a problem, and might be easier to do the sound manually. Thanks, George
This discussion prompted me to contact George Solovay at ITT Products regarding another ITTP item. I just wanted to mention that Mr. Solovay has provided excellent customer satisfaction and that he is a very helpful and knowledgeable individual.
Now, back to the turntable triggering conundrum... Ed
Yes - ASSUMING they two circuits share a common via DCC power. Without knowing the internals of the Walthers DCC TT, we are guessing and hoping it will work. If it does, then it is the equivalent of what you said, the battery negative being commoned to the power supply for the ITT board, and it will all work. If it's not - then it's like having the open negative on the battery and nothing will work.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker When connected to the function output of a DCC decoder, it has the DCC power as a common. Yes, it's low current to trigger the transistor, but there has to be current. If there is no common between the source of the trigger and the ITT circuit, there is no way for current to flow. Think of it this way - if you hooked the + wire of a battery to that trigger input, but left the - of the battery disconnected - how would it work? --Randy
When connected to the function output of a DCC decoder, it has the DCC power as a common. Yes, it's low current to trigger the transistor, but there has to be current. If there is no common between the source of the trigger and the ITT circuit, there is no way for current to flow. Think of it this way - if you hooked the + wire of a battery to that trigger input, but left the - of the battery disconnected - how would it work?
The collector and emmiter run from the ITT power source. So it is a complete circuit. The common (ground) on each (motor and ITT) should be the same potential. It would make no sense for either the ITT or motor to have a floating ground by design. If the motor isn't running it's 0V to the base. A 0V base will automatically break the play circuit. (Non latching)In your battery example, the negative terminal is hooked to a common ground system. Like hooking the negative terminal jumper cable of your car frame and not the battery. It will eventually feed back to the power source as they are indirectly connected.I may be wrong. But this circuit makes sense to me. But I only have degrees in computer science and astrospace, not EE. They only made me take two grueling courses in EE, and one MOOC from MIT (Enough to make me sure I didn't want to deal with the headaches of designing LSICs) So I have a lot of good knowlege, but lack the experience beyond playing with my own circuits. So I will relegate myself and go with your raw experience Randy if my design is questioned.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
The trigger input on the ITT board is a simple transistor relay. The wire out from the motor feed is the base so it uses a minimal of current. The diagram for a single input came from the ITT website itself. The only difference is ITT connected it to a function output of a DCC Decoder.
Only problem I see with that is if there is no common between the motor drive in teh turntable and the ITT board, the sense signal will not work. There has to be a reference for the sense signal to actually do something, just hooking one side of an unrelated circuit to it will not cause it to trigger. It MIGHT work depending on how the turntable electronics connect to the DCC power, if both circuits are powered via DCC. That's why I suggest a small relay across the turntable motor, then it becomes a simple set of contact closures that will defintiely trigger the ITT module.
What I was suggesting was this...(Randy is thinking along the same lines as myself)
Edit:
The problem witht he Walthers DCC turntable is that it doesn;t use a motor drive, it uses switch addresses to move the bridge from setpoint to setpoint. The second problem is that the motor and all the equipment is inside the bridge. It would be fairly easy to tap off the wires going to the bridge drive to trigger a small relay (or solid state relay) - I wouldn't trust that the electronics has enough power to drive the motor AND the ITT sound unit. You would of course be voiding any warranty. The problem is fitting the IIT module and speaker. And getting power to it. With a more traditional type of turntable where the motor drive is under the layout, it's no big deal, you have all the room in the world and can hook up as many wires or extra power supplies as you need.
It might be possible to add another pair of slip rings to the Walthers bridge which would be the contacts to turn the ITT unit on and off, and just locate the small relay inside the bridge, parallel with the motor. Or maybe some way to detect the motion from underneath, as long as it doesn't put a drag on the bridge movement, and use that to turn the ITT unit on and off.
If it's the DCC table, you can program an accessory decoder to the same address as the turnble to turn left and right. Problem is you won't be table to tell when the turntable is done turning to stop the sound.
The only reliable way to do this (and this is "iffy") is to add an extra contact to the bridge.
The extra wire will connect to the sound board trigger input from the positive bridge of a full bridge rectifier in the motor circuit path.
Interesting.
Yeah, you're not gonna get that kind of sound from a 12 volt motor.
Ed
ITT (www.ittproducts.com/products.html ) has 2 variants of turntable sounds-I think the second sound is better.
Wouldn't the motor that drives the turntable make a sound pretty close to the sound that the motor makes that drives the turntable? If ya get my drift.......
Unless, of course, it's an air drive.
That's another option, use a sound decoder to activate the tuirntable. You need one with user-programmable sounds, like Digitrax or Loksound. The Digitrax ones would work fine for this. There was a sound project for the old ones that effectively made it a generic DCC controlled sound block, you just loaded whatever sound files you wanted. This would be pretty easy too make, since there are no speed ztep issues or anything, basically turntable on and turntable off - so no speed step sounds, tranistion between speed step sounds, etc. Just one sound that comes on when the mootor goes on, foorward or reverse.
I would think it would be wired in paralel to the TT-decoder. In other words, the output from the TT-decoder should be wired to both the TT motor and to the decoder. I would guess the TT decoder doesn't have speaker out connections?
But I'd check the mfg's documentation. Should be available online. Never heard of a sound module for a TT, but I could see something like that.
Mike Lehman
Urbana, IL
Hello friends, I have a Walthers 130´Turntable (H0). I will adding sound from ITT. Has this anyone do? I think, i must combine the wire from the TT-Decoder with the sound-module-but how?