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DCC Controlled (PECO) Turntable Project using a Arduino Uno


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Looks like you got the last one.

So i bought one of these:

 

http://www.ebay.co.uk/itm/121679235010

 

Nice and slim to go under new baseboard.

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Hi Dave, can you post details of your stepper, sounds interesting.

Ray.

Hi Ray,

 

Looks like you and Ian made the jump to 0.9° steppers.  I wonder if the one you ordered will have enough torque, but with your gear reduction I suspect it might.

 

The one I got was this one from Stepperonline.com which has 400 steps per rotation.  Max speed is set at 100 and acceleration at 70 and it is silky smooth.  BTW the sketch in Step 5 results in 90° back and forth motion so I adjust all the setting in these sketches by a factor of 2.  3,200 steps is 180°, 4,800 steps is 270°, etc.

 

I'm using an HO 72' ExactRail plate girder bridge trimmed down for the bridge on my turntable and the pit is not yet built.  I have a CUI AMT203-V absolute encoder instead of the Hall Effect sensor (long story) for auto-align during startup.  Will need to add the CUI sketch to the modified Cambriancoaster sketch but that will have to wait a few days.  Preparing and loading two small portable layouts for a train show this weekend in Lehi, Utah.  Will post the sketch when I get the bugs worked out.

 

Thanks again for all you have done.

 

Dave

St George, Utah

Edited by HVT Dave
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  • 3 weeks later...

Hi All,

Just thought i'd post a picture of the latest project i'm working on.

 

post-11105-0-11623800-1517262481_thumb.jpg

 

This turntable project uses the same DCC interface and reference sensor (yet to be connected) as before but utilises the Arduino Nano and A4988 Stepper Driver. A version of the PCB is available from DCCinterface.com either as a PCB only or fully populated board. Also an off the shelf display/keyboard has been attached to the I2C pins of the Nano.

This will give manual control of up to 100 stations on the turntable making this suitable for DC users.

Of course DCC users can use as before by sending a DCC Accessory command via the DCC interface (as well as manual control).

 

Instead of a direct drive to the turntable, this time i'm using a toothed belt with 4:1 ratio (20:80) pulleys and a slimline stepper as it has to fit under a shallow exhibition baseboard.

Most of the code has been written and tested, just waiting for my new turntable kit to arrive so i can get it built up. Will post a video of progress so far later. 

 

Ray.

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Hi Ian, 

 

As you say, useful for DC users, but i thought it would have made more sense just to add the I2C pin outs to the DCC Interface board and then it would be usable for both DCC or DC users. DC users would just omit the DCC interface components, and DCC users would have the additional benefit of an optional manual control keypad/display. Even the same sketch would work for both DC and DCC.

Anyway, thats what i have done.

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Thought i'd just post where i'm up to with the new Cowans & Sheldon 60ft turntable build for a new layout.

 

This is the toothed belt drive from the stepper, the slotted holes allow belt tension to be adjusted.

 

post-11105-0-58405000-1518686072_thumb.jpg

 

Mounted on the bottom of the turntable well.

 

post-11105-0-17963200-1518686096_thumb.jpg

 

Turntable Deck and Well still need to be finished, waiting for some decent weather for spraying.

 

post-11105-0-91248100-1518686039_thumb.jpg

 

Full details of the build are here:

http://www.rmweb.co.uk/community/index.php?/topic/62699-rays-4mm-workbench-metalsmiths-turntable-end-of-p13/?p=3038724

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  • 2 months later...
  • 3 weeks later...

 

just thought id upload some more pictures of my touch screen interface for the turntable...

 

the main screen

 

 
 
this is the 1st settings screen..
 
 
 
 
 
 
 
 
 

The system uses the I2C interface to send commands, so hopefully should be easy to use for other projects too.

 

Hi ianjeffery

 

I made a system like this for my turntable and a traverser with 4x4 keyboard. 

This is very interesting because you have a touch screen that gives a more beautiful layout, and dont have contacts like keyboard.

Could you please if possible share with us the sketch of this interface..?

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  • 7 months later...

 

just thought id upload some more pictures of my touch screen interface for the turntable...

 

the main screen

 

 
 
this is the 1st settings screen..
 
 
 

The system uses the I2C interface to send commands, so hopefully should be easy to use for other projects too.

 

 

Wow that looks nice Ian, are you planning to sell kits for the touchscreen?, will it be able to store locations?

 

i got my turntable working on my test board, (scratch built with a copper clad board with bits of Dapol kit) using one of the earlier sketches can't think which atm. i really do need to get back on it hence checking the updates on thread.

 

i got around power by making a 360 degree ring with two contacts (one for each rail) then in the code one of the arduino pins flips depending on if the table is at head or tail (depending on output polarity) at the moment this is an additional line on each position/road in the code in turn this pin is switching a dpdt relay flipping the polarity to make sure its correct, this happend so quick the sound locos don't seem to notice :) 

 

the other mod i had was to use the servo output in a previous sketch to move a micor servo to position a small rubber against my contact ring just to prevent drift when the motor was off, i#m going to be building up another tt soon, so defo going to get one of your kits ian, might actually get two and swap out all the boards on my first, its a much tidier solution. 

 

Jon

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Hi All,

Just thought i'd post a picture of the latest project i'm working on.

 

attachicon.gifIMG_0386.jpg

 

This turntable project uses the same DCC interface and reference sensor (yet to be connected) as before but utilises the Arduino Nano and A4988 Stepper Driver. A version of the PCB is available from DCCinterface.com either as a PCB only or fully populated board. Also an off the shelf display/keyboard has been attached to the I2C pins of the Nano.

This will give manual control of up to 100 stations on the turntable making this suitable for DC users.

Of course DCC users can use as before by sending a DCC Accessory command via the DCC interface (as well as manual control).

 

Instead of a direct drive to the turntable, this time i'm using a toothed belt with 4:1 ratio (20:80) pulleys and a slimline stepper as it has to fit under a shallow exhibition baseboard.

Most of the code has been written and tested, just waiting for my new turntable kit to arrive so i can get it built up. Will post a video of progress so far later. 

 

Ray.

 

Ray where did you source the belt drive from?, i had a look at your other thread, i like that the shaft is then supported above and below the large gear

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Ray where did you source the belt drive from?, i had a look at your other thread, i like that the shaft is then supported above and below the large gear

 

Hi Jon,

The drive belt and pulleys were from RS components. If you want the part numbers I'll dig them out for you.

Ray.

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That's would be awesome ray

 

 

Hi Jon.

Here are the part numbers I used. 

 

MXL Plastic Pulley with insert teeth 20

Stock no.: 7784718

 

MXL Plastic Pulley teeth 80, bore 8mm

Stock no.: 7784862

 

MXL Rubber Timing Belt W1/4, L 16.00 in.

Stock no.: 7785098

 

I bought a few shorter timings belt later from the same range. Not sure which one I ended up using.

 

MXL Rubber Timing Belt W1/4, L 12.80 in.

Stock no.: 7785082

 

MXL Rubber Timing Belt W1/4, L 10.40 in.

Stock no.: 7785070

 

Ray.

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  • 3 weeks later...

Just playing with my turntable control, as I’m installing i2c remote control, and whilst I’m at it, I wanted to stop the damn thing whining, so I started to look for the data sheet for the A4899 driver.

 

found this in case anyone else is searching

 

http://html.alldatasheet.com/html-pdf/338780/ALLEGRO/A4988/2974/10/A4988.html

 

It’s not ideal (at least I couldn’t download it) but at least explains the not-enable and not-sleep pins, which I have now connected to the slave Arduino that controls it.  More in my Arduino thread linked in my signature.

 

atb

Simon 

 

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Very interesting project. My TT pivots on a 1/4” stereo jack plug and socket which powers the bed and indicator leds for polarity, but to date installing a motorised drive has been a challenge as the jack is where a drive motor would normally go. Gears and pulleys and belts, etc have also been looked at but so far nothing finalised. However if and when it is then at least the indexing methodology is all squared away as documented in this thread - thanks for sharing.

Rob

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