With an arpschuino² : the code

The default code of the arpschuino² does not allow stepper motors to be controlled, the card will have to be reprogrammed.

To do that we need the arduino IDE.

If it's not already done, install the core arpschuino as described in this tutorial.

Since version 1.1.0, the arpstepper library is installed automatically with the arpschuino core. If you have an earlier version, please update as shown in the same tutorial.

We are going to use the arpschuino_4steppers code which is available in the examples of the ArpStepper library, from version 1.1.0 of the arpschuino core.

This code is functional, but some adjustments are necessary to adapt it to your configuration, but rest assured: no need to be a programmer to tackle this task!

The parts in light gray and/or preceded by // are comments, they are not taken into account in the program, they are addressed to the human who reads this code (you).

      Lines preceded by // = commented lines (disabled)

definition of the number of motors to be controlled:

	#define nbr_motor 4
					

Creation of objects :

	
	// configuration matérielle, connexion et réglage du pilote :
	//hardware configuration, driver connection and adjustment :
	//(pin dir,pin pull, step_per_revolution)					
	ArpStepper stepper0(Arp1,Arp0,200);
	ArpStepper stepper1(Arp3,Arp2,6400);
	ArpStepper stepper2(Arp5,Arp4,200);
	ArpStepper stepper3(Arp7,Arp6,800);					
	
	//ArpStepper stepper4(Arp9,Arp8,800);
	//ArpStepper stepper5(Arp11,Arp10,800);
	//ArpStepper stepper6(Arp13,Arp12,800);
	//ArpStepper stepper7(Arp15,Arp14,800);
	
					

We "create" our stepper objects in the code. Here we called them stepper0, stepper1 ... But we could have given them any name.

In brackets we indicate, respectively, the pin of the arpschuino connected to the DIR of the driver, the one connected to the PULL (or STEP) and finally the number of steps per revolution that we defined when configuring the driver.

In this example, 4 of these objects are created, the following are commented out (disabled).

Depending on your usage, comment out (by putting // at the start of the line), or uncomment part of these lines to create the number of motors you want.

Support for the arpdress board :

	Arp_arpdress_board();
					

Here we tell the arpschuino to support the arpdress board. If you do not use it, comment this line and define a fixed address by writing for example:

	address=24;
					

Initialization:

	//(RPM_min(>0), RPM_max , revolutions, resolution(default 255))				
	stepper0.init(1, 200, 12, _8bits);
	//stepper0.invert_rotation(true);
	stepper1.init(1, 100, 12, _16bits);
	stepper2.init(2, 300);
	stepper3.init(2, 300, 12);  
	
	//  stepper4.init(2, 300, 12, _8bits);
	//  stepper5.init(2, 300, 12, _8bits);
	//  stepper6.init(2, 300, 12, _8bits);
	//  stepper7.init(2, 300, 12, _8bits);  
	 
					

Here we will initialize the behavior of our steppers.

Depending on the number of motors used, we comment or uncomment, as for the creation of objects.

The first two parameters in brackets concern speed: minimum speed and maximum speed in revolutions per minute. The maximum attainable speed depends on the motor used, if you request too high a speed the motor will lock ...

The third parameter defines the total revolutions of the motor in number of revolutions. You can put a floating-point values here.

The last parameter is optional and concerns the command, _8bits for a command with a single DMX channel, _16bits for a command on two channels as for an automated projector. If this last parameter is not filled in, the command will be in 8 bit by default.

The line //stepper0.invert_rotation(true); is commented here, uncommenting it reverses the direction of rotation of the motor concerned.

action !

	 stepper0.perform();
	 stepper1.perform();
	 stepper2.continuous();
	 stepper3.perform();  
		
	//  stepper4.perform(); 
	//  stepper5.perform();
	//  stepper6.perform();
	//  stepper7.perform();  
		 
					

We indicate here the action to be performed, 2 are available, perform () and continuous ().

With perform() we precisely control the position of the motor, according to the total revolutions defined previously.

With continuous(), the motor is in continuous rotation mode. We control the direction and the speed.

patch :

The refresh() function updates the orders given to the motors. In our case the order is in DMX but the library also lends itself to other types of control, MIDI, OSC or potentiometer.

Placed here (in the frame_received() loop), this function will be executed each time a DMX frame is received.

So we indicate here which DMX circuits will be used to control our motors

   stepper0.refresh(DMX.RxBuffer[0], DMX.RxBuffer[1]);
					

DMX.RxBuffer[0], c'est la valeur DMX reçue. Le [0] (entre crochets) s'aditionne à l'adresse DMX de l'arpschuino definie plus haut. Autrement dit c'est l'adresse 1 si l'arpschuino est adressé en 1, 24 s'il est adressé en 24... Adresse de la carte + [0].

Dans notre exemple, la position du stepper0 est controllé par le premier circuit, sa vitesse par le second.

   uint16_t position_stepper1 =(DMX.RxBuffer[2]<<8) | (DMX.RxBuffer[3]); 
   stepper1.refresh(position_stepper1, DMX.RxBuffer[4]);
					

We had initialized stepper1 in _16BITS mode, so the position is controlled by 2 circuits.

The line uint16_t position_stepper1 =(DMX.RxBuffer[2]<<8) | (DMX.RxBuffer[3]); transform the 8-bit levels of two channels into a single 16-bit value (called position_stepper1).

All that remains is to report it in refresh () : stepper1.refresh(position_stepper1, DMX.RxBuffer[4]);

   stepper2.refresh(DMX.RxBuffer[5], DMX.RxBuffer[6]);
   stepper3.refresh(DMX.RxBuffer[7], DMX.RxBuffer[8]);
					

Same for the last two engines. The stepper2 is in continuous mode, the first parameter controls the direction of rotation, the second is speed.

Let's try ?

All you have to do now is to power the arpschuino (the red led should light up) and the driver and to connect the Dmx cable (or send Artnet wifi with the arpschuino32). As soon as we receive a signal, the green LED starts flashing rapidly.

We can now test the assembly by raising the levels of the DMX addresses concerned.

In perform mode, you precisely control the position of the motor. The first DMX parameter (or the first two, in 16-bit mode) defines the position. The second (or third), speed.

In continuous mode, the motor rotates continuously. The first DMX parameter controls the direction, the second the speed.

Is the stepper motor run ?

Yeh it's work !

In case of difficulties, do not hesitate to ask questions on the arpschuino forum .