Turntable Drive

Hello
My project for the spring is to build a turntable and operate it from my Massoth DCC system. Can anybody recommend a cheap decoder that will simply go forwards and backwards at variable speed?

Bill
 
Thanks for that. The turntable is virtually built and I have it running of a switchable battery supply but I would like it to be remote. The motor pulls about 200mA so 1A would be playing safe. Can you recommend a decoder?

Bill
 
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I have an old LGB55020 on my desk here, Bill - you can have it for the cost of post and packing, if it's any use to you.....?

Feel free to PM me (sorry, "start a conversation", I mean - I'll never get used to calling it that....).

Jon.
 
I have an old LGB55020 on my desk here, Bill - you can have it for the cost of post and packing, if it's any use to you.....?

Feel free to PM me (sorry, "start a conversation", I mean - I'll never get used to calling it that....).

Jon.
John
Still finding my way round this new version of the forum. How do I start a conversation?
 
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Try the "Envelope" at the top right. Next to the "Bell".
 
Best not to post email addresses in threads, they could be harvested by bots and used for spam.
 
Good advice Nick. I have suitably disguised it.Not sure how efficient this is these days but we can only try.
 
Oh so that is what that pointy down arrow in a Square is for! Went to Conversations via my profile all the time!
JonD
 
The only problem with turntables is indexing.. - getting them to stop 'just right' to line the tracks up.
We have one on the 'Harz layout, and it is a bit of a wotsit to get lined up at times...
ADM (Ithink it is) do a VERY nice stepper motor driven unit which you can program to remember where each point is.. Allegedly, if you have a decent depth pit (water!), it is robust enough to go outside.
Beautiful piece of engineering, you add your own deck-infrastructure.

No connection, just impressed when I saw it at the Stafford model show..

Only down-side.. It costs the same as a new loco..
 
I was going to say, a stepper motor would be better than just relying on a DC motor and lining up by eye. Rather more complex to implement though, and a constant current draw to maintain position unless you also implement some sort of locking mechanism.

Back in the early 80s my college project involved controlling a robotic arm with a BBC Micro computer, that was all done with stepper motors. Marvellous fun, I created my own interpreted "language" to program the arm to carry out various tasks.
 
I'm thinking that if Bill has made his drive sufficiently geared-down so that when it's driven via his Navi he can get it to move VEEEEEERY slowly at speed step 1, then lining up visually shouldn't be too difficult. Maybe it could have some kind of VERY gentle spring-loaded detent at each exit point, so that provided you get it in roughly the right position it will click into place properly aligned, but not have so much spring pressure that the motor can't easily overcome it to move to the next position..... just thinking off-the-cuff here, got a vague mental image of what I mean but no idea how to actually build it.... ;)

Jon.

Edit: thinking of something like a ball bearing with a very weak spring behind it, aligned with the centreline of the deck, and rolling round the inside of the pit. Each track position around the pit has a shallow depression that the ballbearing clicks into when it's aligned, but a bit of power to the motor would easily overcome the spring pressure when you want to move to another position.....
 
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