Kyle of Lochalsh

Hi all
I don't know if anyone is interested in the next part of my Kyle build. This will be a DCC Arduino operated turntable. If so should I post the build here or somewhere else.
Thanks
Bob

 

Hi Paul
I have got on pretty well thanks. I did read your 101 and found it very helpful.
Hi Toto
I will post it here if that's OK it will keep the Kyle build all together.
Thanks
Bob

 

Turntable Build
Part One
Parts Used
So I am using the following:

1 x Peco LK55 00/H0 turntable.

https://tinyurl.com/ycxbqyop

1 x DCC Interfaces DCC turntable board

1 x ArduinoNano

https://www.dccinterface.com/shop/

A RS Components SR 15C-A3 Hall effect sensor RS Part number 370-6896

A Powerful Magnet

https://tinyurl.com/ybntb74e

2 Pieces of 5 mm thick acrylic

https://tinyurl.com/y78z6ekq

1 x 60 tooth gear RS Part number

286-5720

1 x 10 tooth gear RS Part number

744-946

1 x timing belt 102 teeth 510 long RS Part number

474-5583

2 x miniature ball bearings 8mm in dia 22 out dia RS Part number

618-9957

3 x M4 countersunk 35 mm long machine screws washers and nuts

https://tinyurl.com/ya3yzmcy

3 x Circuit board standoffs

https://tinyurl.com/y7ebrqqk

Plus 3 x 3d Printed columns and one base bearing holder print.

The links are where I got my Parts from, there are obviously many other places to get them from.

Thanks Bob

 

Part Two


First can I thank Ray (Tender) on RMWeb for the time and effort he has put into the following topic.

https://tinyurl.com/ybduy5kj

Which gave my idea to build on.

And also to Paul for his Arduino 101.

And for Ian at DCC Interface.com for his excellent products and his help.

Kyle used only one feed to the turntable as in this diagram.


So I will only need to have one front station entry and one back station entry. But I will show how to to modify the program enable as many roads as you need on your layout.

The first thing to find out was how I was going to fix the turntable base to the layout. I wanted to be able to remove the table as easily as possible. So I decided that all the mechanics and electrics are mounted on a base fitted to the table.

I then cut the hole in the layout this was 310mm Dia. and had a recess built in to let the table be flush to the layout. As in the diagram below.

Thanks Bob

 

Sorry Toto they are just links to the web sites
.
Pics to follow.
Thanks
Bob

 

Part Three


Next I drilled three M4 holes and countersunk them at the drain cover indentations. These holes are at a 150 mm dia. Circle. Then made the acrylic parts for the mounting plates.

As in this picture I am lucky enough to have a cnc laser cutter (bought off Ebay in a dead state, very cheap). So I cut the acrylic on this machine. I will make the DXF files available to anyone that would like them.

The eagle eyed among you may have seen that the circular acrylic is actually Two 2mm thick discs as I ran out of 5mm thick stock. The bearings are just pressed in.

 

Part Four
Parts

That's it for today
Be seeing you
Bob

 

PART FIVE


As I said before I am using a DCC interface board. This board uses an Arduino Nano and a A4988 motor driver board.

I had before discovering Ian’s web site already got a Arduino Uno and a A4988 driver board running a bipolar stepper motor after adapting Tender’s programme on RMWeb

http://www.rmweb.co.uk/community/in...d-peco-turntable-project-using-a-arduino-uno/

This is the circuit that he was using. As I did not have an Adafruit motor controller but I did have a Pololu A4988 I had to change the circuit to match.

Here is a block diagram of the circuit

And here is the fritzing circuit

I then discovered Ian’s DCCinterface.com board and to save time and trouble of making my own I bought one his boards. This board incorporates all the parts that I had already got working on a breadboard. (Except for one mod I had to make because of the sensor I was using).

 

PART SIX

This is how the A4988 is connected to the rest of the circuit.

The connections are as follows
A4988 Nano
STEP D4
DIR D5
EN D6
VDD 5V
GND GND

This is the table of microsteps for the A4988

The top row of the 5×2 pin headers (on the DCC INTERFACE BOARD) are connected to +5v.(nearest pins to the bottom of the picture below) the bottom row are connected to the A4988 pins ( Sleep, Reset, MS1, MS2, MS3). With no jumpers connected, MS1, MS2 and MS3 are in the LOW position ( in relation to the table below). To set a MicroStepping to high, use a jumper to connect the A4988 pin to +5v – hence making it HIGH.

E.g. for Eighth Step – place a jumper on MS1 and 5v , and MS2 and 5v. For Full steps, place no jumpers.

I set mine to MS2 High = Quarter Step

Important : Make sure there is a jumper between the SLEEP and RESET pins.

As in the following picture

 

Hi Paul
yes I know of the accelstepper lib see next episode
Bob

 

PART SEVEN

The modification I mentioned in the last part is that the sensor I am using needs to have a 10K pullup resistor fastening the signal out pin to 5Volts.

I just fastened this to the leads on the connector as the following picture.

The other modification was to the programme as this sensor goes LOW so the programme needs to change from HIGH to LOW.

So here is the Arduino programme straight of the DCC site.

Thank you Ian.

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// DCC Stepper Motor Controller ( A4988 ) Example

// See: https://www.dccinterface.com/how-to/assemblyguide/

//

// Author: Alex Shepherd 2017-12-04

//

// This example requires two Arduino Libraries:

//

// 1) The AccelStepper library from: http://www.airspayce.com/mikem/arduino/AccelStepper/index.html

//

// 2) The NmraDcc Library from: http://mrrwa.org/download/

//

// Both libraries can be installed via the Arduino IDE Library Manager

//


#include <AccelStepper.h>

#include <NmraDcc.h>


// Uncomment to enable Powering-Off the Stepper if its not running

#define STEPPER_ENABLE_PIN 6


// Home Position Sensor Input

#define HOME_SENSOR_PIN 3


typedef struct

{

int address;

int stationFront;

int stationBack;

}

DCCAccessoryAddress;

DCCAccessoryAddress gAddresses[2];


// for a 1.8 deg stepper, there are 200 full steps

#define FULL_STEPS_PER_REVOLUTION 200


// Uncomment the lime below for the Driver Board Settings

//#define FULL_TURN_STEPS (FULL_STEPS_PER_REVOLUTION) // full steps

//#define FULL_TURN_STEPS (FULL_STEPS_PER_REVOLUTION * 2) // 1/2 steps

#define FULL_TURN_STEPS (FULL_STEPS_PER_REVOLUTION * 4) // 1/4 steps

//#define FULL_TURN_STEPS (FULL_STEPS_PER_REVOLUTION * 8) // 1/8 steps

//#define FULL_TURN_STEPS (FULL_STEPS_PER_REVOLUTION * 16) // 1/16 steps


// home location

#define entryStation FULL_TURN_STEPS / 3


volatile bool bInterruptDetected = false;

bool bHomePositionFound = false;


// Now we'll wrap the stepper in an AccelStepper object

AccelStepper stepper1(1, 4, 5);


NmraDcc Dcc ;

uint16_t lastAddr = 0xFFFF ;

uint8_t lastDirection = 0xFF;

//

// Decoder Init

//

void ConfigureStations()

{

// this is home

gAddresses[0].address = 200;

gAddresses[0].stationFront = entryStation;

gAddresses[0].stationBack = entryStation + (FULL_TURN_STEPS / 2);


gAddresses[1].address = 201;

gAddresses[1].stationFront = ((FULL_TURN_STEPS / 3) * 2);

gAddresses[1].stationBack = ((FULL_TURN_STEPS / 3) * 2) + (FULL_TURN_STEPS / 2);

}


// This function is called whenever a normal DCC Turnout Packet is received

void notifyDccAccTurnoutOutput( uint16_t Addr, uint8_t Direction, uint8_t OutputPower )

{

Serial.print("notifyDccAccTurnoutOutput: ") ;

Serial.print(Addr,DEC) ;

Serial.print(',');

Serial.print(Direction,DEC) ;

Serial.print(',');

Serial.println(OutputPower, HEX) ;


for (int i = 0; i < (sizeof(gAddresses) / sizeof(DCCAccessoryAddress)) ; i++)

{

if ((Addr == gAddresses.address) && ((Addr != lastAddr) || (Direction != lastDirection)) && OutputPower)

{

lastAddr = Addr ;

lastDirection = Direction ;



Serial.print(F("Moving to Station : "));

Serial.println(i, DEC);


#ifdef STEPPER_ENABLE_PIN

stepper1.enableOutputs();

#endif

if (Direction)

{

Serial.print(F("Moving to Front Position : "));

Serial.println(gAddresses.stationFront, DEC);

stepper1.moveTo(gAddresses.stationFront);

break;

}

else

{

Serial.print(F("Moving to Back Position : "));

Serial.println(gAddresses.stationBack, DEC);

stepper1.moveTo(gAddresses.stationBack);

break;

}

}

}

};


bool lastIsRunningState ;


void setupStepperDriver()

{

#ifdef STEPPER_ENABLE_PIN

stepper1.setPinsInverted(false, false, true); // Its important that these commands are in this order

stepper1.setEnablePin(STEPPER_ENABLE_PIN); // otherwise the Outputs are NOT enabled initially

#endif



stepper1.setMaxSpeed(1000.0);

stepper1.setAcceleration(1000);

stepper1.setSpeed(600);



lastIsRunningState = stepper1.isRunning();

}


void moveToHomePosition()

{

pinMode(HOME_SENSOR_PIN, INPUT_PULLUP);

attachInterrupt(digitalPinToInterrupt(HOME_SENSOR_PIN), interruptEvent, RISING);


bInterruptDetected = false;



Serial.println(F("Performing 2 complete turns to find home."));

stepper1.move(FULL_TURN_STEPS * 2);

}


void interruptEvent()

{

detachInterrupt(digitalPinToInterrupt(HOME_SENSOR_PIN));

bInterruptDetected = true;

}


void setupDCCDecoder()

{

Serial.println(F("Setting up DCC Decorder..."));


// Setup which External Interrupt, the Pin it's associated with that we're using and enable the Pull-Up

Dcc.pin(0, 2, 1);



// Call the main DCC Init function to enable the DCC Receiver

Dcc.init( MAN_ID_DIY, 10, CV29_ACCESSORY_DECODER | CV29_OUTPUT_ADDRESS_MODE, 0 );

}


void setup()

{

Serial.begin(115200);

while(!Serial); // Wait for the USB Device to Enumerate


Serial.println(F("Example Turntable Program - www.dccinterface.com"));


ConfigureStations();



setupStepperDriver();


Serial.println(F("Finding home...."));

moveToHomePosition();

}


void loop()

{

if (bInterruptDetected)

{

bInterruptDetected = false;

bHomePositionFound = true;


Serial.println(F("Found Home - Ssetting Current Position to 0"));


stepper1.setCurrentPosition(0);


Serial.print("Moving to position ");

Serial.println(entryStation, DEC);

#ifdef STEPPER_ENABLE_PIN

stepper1.enableOutputs();

#endif

stepper1.moveTo(entryStation);


setupDCCDecoder();

}


if (bHomePositionFound)

{

// You MUST call the NmraDcc.process() method frequently from the Arduino loop() function for correct library operation

Dcc.process();

}


// Process the Stepper Library

stepper1.run();


#ifdef STEPPER_ENABLE_PIN

if(stepper1.isRunning() != lastIsRunningState)

{

lastIsRunningState = stepper1.isRunning();

if(!lastIsRunningState)

{

stepper1.disableOutputs();

Serial.println(F("Disable Stepper Outputs"));

}

}

#endif

}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////





Now I am using a stepper motor with 1.8 degree steps this gives you 200 steps for a complete revolution of the motor.

As I am using the 60 tooth and 10 tooth gear to give a smoother movement I needed to change the steps per revolution.


Original line in programme

#define FULL_STEPS_PER_REVOLUTION 200


My version


60 to 10 =6 to 1 so 200 x 6 = 1200


#define FULL_STEPS_PER_REVOLUTION 1200


Now I am using ¼ step microstepping (MS2 linked to 5V)


So there are 4800 steps for a complete revolution of the turntable deck.


this means you can have 4800 different stations (HE HE )

The modification to the programme for the sensor is as follows





Original code

void moveToHomePosition()

{

pinMode(HOME_SENSOR_PIN, INPUT_PULLUP);

attachInterrupt(digitalPinToInterrupt(HOME_SENSOR_PIN), interruptEvent, RISING);


My code

void moveToHomePosition()

{

pinMode(HOME_SENSOR_PIN, INPUT_PULLUP);

attachInterrupt(digitalPinToInterrupt(HOME_SENSOR_PIN), interruptEvent, LOW);


Just the one word change RISING to LOW

Now the programme will run the turntable albeit a little fast.

That’s next

 

PART EIGHT

Now to slow things down

These are the original lines of code

stepper1.setMaxSpeed(1000.0);

stepper1.setAcceleration(1000);

stepper1.setSpeed(600);



This is what I ended up with there may be better ways of doing this but this works just fine.


stepper1.setMaxSpeed(50.0);

stepper1.setAcceleration(500);

stepper1.setSpeed(50);



By the way if your deck moves the opposite way around than you want it to you only have to change two of the wires that connect the stepper motor to the board.

I.E. swop about 1A with 1B
that it for now unless you have any questions
Be seeing you
Bob