Week 11: Output Devices

Many thanks to Aleksandra Konopek who gave me an advice to take a look at the page of Funduino and to test the circuits. Thanks to Peter von der Bey for the helpf ull tipps about the wiring and our instructor Tobias Poppe for helping me to solve the problem which occured with the wiring the laboratory power supply with my board.
This week, we should issue a signal and use a self made board for it. I would have liked to build a new board that I could tailor to the task. Unfortunately, the time this week was not enough for milling a new board.

I have decided to test the small blue servo motor SG90 with the plastic case this week. I also wanted to test the RGB LED. The green RGB LED should light up whenn the green segment of the logo turns and so on .
Servo where to purchise .
Servo control using Arduino IDE.

A few excerpts from the data sheet with the basic data of the servo:
The first attempt to operate the servos I had done with Arduino UNO and that had worked.
For the wiring only three cables were needed:
VCC, Red cable (+)
GND, Brown cable (-)
and PWM Signal, Orange cable

Something I did not know as I used the Funduino code example was this: "Servo can rotate approximately 180 degrees (90 in each direction)". In the Funduino code ther are commands to turn up to 180°. This could damage the servo over the long term using.
I found the following script for the servo control at Funduino ( FUnduino.de ) and used it for the control. I just extended it to three servos. At first, I had the servos switched at the same time (with a PIN) and later one by one so I needed three variables .

Three servos I conected as to see on the folowing image, where I used Fritzing.app

Fritzing.app beta version
to visualise the conections.
Folowing image shows the prozes of wiring the Arduino board in Fritzing.app. I decided to use Arduino-Symbolics instead of Atmega328p becauese it was simplier than insluding many headers adittionally to atmega and other components.

Wiring step
In Fritzing.app you cann also switch to the board layout and do all the settings in that layer, as same as using Eagle.

Boardshema not finished as I did not used it.
This is how the wiring of the breadbord looked like for my servo motor connection. The pins on the Arduino board are not the same as the pins I used on Atmega328p.

Wiring three servos

What is PWM? (Source: barrgroup.com)

        
#include         // Servo Library is called. Will be needed, for the easier control of the servo motor  
 
Servo servoblue;          // For this programm here will be created a servo named „servoblue“
Servo servogreen;
Servo servored;
 
void setup()
{

servoblue.attach(PD5);      // This is the Information that servo connecting
                            //the control wire (blue) is connected with  pin PD5 . You can take 
                            //any other pin for this connection.
servogreen.attach(PD6);
servored.attach(PD5);
}

void loop()

{     //In the „loop“ using the write-command „servoblue.write(Grad)“
      //the servo will be controled. Between the positions (Grad) there 
      //will be a pause, so the servo becommes enough time to reach the desired position.

servored.write(0);      //Activate position 1 on servored with the angle 0 °
delay(3000);            //The program stops for 3 seconds

servogreen.write(0);    //Activate position 1 on servogreen with the angle 0 °
delay(3000);           

servoblue.write(0);     //Activate position 1 on servoblue with the angle 0 °
delay(3000);            

servored.write(30);     //Activate position 2 on servored with the angle 30 °
delay(3000);           

servogreen.write(30);   //Activate position 2 on servogreen with the angle 30 °
delay(3000);           

servoblue.write(30);    //Activate position 2 on servoblue with the angle 30 °
delay(3000);         

servored.write(60);     //Position 3 on servored control with the angle 60 °
delay(3000);            
servogreen.write(60);   //Position 3 on servogreen control with the angle 60 °
delay(3000);            
servoblue.write(60);    //Position 3 on servoblue control with the angle 60 °
delay(3000);           

servored.write(90);     
delay(3000);           
servogreen.write(90);    
delay(3000);
servoblue.write(90); 
delay(3000);

servored.write(60);
delay(3000);
servogreen.write(60); 
delay(3000);
servoblue.write(60); 
delay(3000);

servored.write(30); 
delay(3000); 
servogreen.write(30); 
delay(3000); 
servoblue.write(30); 
delay(3000); 

}  

        #include         // Servo Library is called. Will be needed, for the easier control of the servo motor  
 
        Servo servoblue;          // For this programm here will be created a servo named „servoblue“
        Servo servogreen;
        Servo servored;

        int LEDred = PD5;       // Colour red will be at pin PB2 (PWM)
        int LEDgreen = PD3;     // Colour blue at PB1 (PWM)
        int LEDblue = PD6;      // Green at Pin PD6 (PWM)
        int p = 3000;           // p is a pause with 1000ms (1 second)
        int brightness1a = 100; //  Value between 0 and 255 - indicates the luminosity of each color
        int brightness1b = 200; 
        int brightness1c = 200; 
        int dark = 0;           // Value 0 means Voltage 0V - so LED off.


        void setup()
        {

        servoblue.attach(PD7);      // This is the Information that servo connecting
                                    //the control wire (blue) is connected with  pin PD5 . You can take 
                                    //any other pin for this connection.
        servogreen.attach(PB4);   
        servored.attach(PD4);

        pinMode(LEDred, OUTPUT);
        pinMode(LEDblue, OUTPUT);
        pinMode(LEDgreen, OUTPUT);
        pinMode(LEDred, OUTPUT);

        }

        void loop()

        {     //In the „loop“ using the write-command „servoblue.write(Grad)“
              //the servo will be controled. Between the positions (Grd) there 
              //will be a pause, so the servo becommes enough time to reach the desired position.

        servored.write(0);                  //Activate position 1 on servored with the angle 0 °
        analogWrite(LEDred, brightness1a);  // red LED on
        delay(p);                           //The program stops for p seconds

        servogreen.write(0);                  //Activate position 1 on servogreen with the angle 0 °
        analogWrite(LEDred, dark);            // red LED off
        analogWrite(LEDgreen, brightness1b); // green LED on         
        delay(p);  

        servoblue.write(0);                   //Activate position 1 on servoblue with the angle 0 °
        analogWrite(LEDgreen, dark);        // green LED off
        analogWrite(LEDblue, brightness1c);   //  blue LED on
        delay(p);            

        servored.write(30);     //Activate position 2 on servored with the angle 30 °
        analogWrite(LEDblue, dark);         // blue LED off
        analogWrite(LEDred, brightness1a); 
        delay(p);           

        servogreen.write(30);   //Activate position 2 on servogreen with the angle 30 °
        analogWrite(LEDred, dark);            // red LED off
        analogWrite(LEDgreen, brightness1b);
        delay(p);           

        servoblue.write(30);    //Activate position 2 on servoblue with the angle 30 °
        analogWrite(LEDgreen, dark);        // green LED off
        analogWrite(LEDblue, brightness1c); 
        delay(p);         

        servored.write(60);     //Position 3 on servored control with the angle 60 °
        analogWrite(LEDblue, dark);         // blue LED off
        analogWrite(LEDred, brightness1a); 
        delay(p);            

        servogreen.write(60);   //Position 3 on servogreen control with the angle 60 °
        analogWrite(LEDred, dark);            // red LED off
        analogWrite(LEDgreen, brightness1b);
        delay(p);            

        servoblue.write(60);    //Position 3 on servoblue control with the angle 60 °
        analogWrite(LEDgreen, dark);        // green LED off
        analogWrite(LEDblue, brightness1c); 
        delay(p);           

        servored.write(30); 
        analogWrite(LEDblue, dark);         // blue LED    
        delay(p);           

        servogreen.write(30);    
        analogWrite(LEDgreen, brightness1b);
        delay(p);

        servoblue.write(30); 
        analogWrite(LEDgreen, dark);        // green LED off
        analogWrite(LEDblue, brightness1c); 
        delay(p);

        servored.write(15);
        analogWrite(LEDblue, dark); 
        delay(p);

        servogreen.write(15); 
        analogWrite(LEDgreen, brightness1b);
        delay(p);

        servoblue.write(15); 
        analogWrite(LEDgreen, dark);        // green LED off
        analogWrite(LEDblue, brightness1c); 
        delay(p);

        servored.write(0); 
        analogWrite(LEDblue, dark); 
        delay(p); 

        servogreen.write(0); 
        analogWrite(LEDgreen, brightness1b);
        delay(p); 

        servoblue.write(0); 
        analogWrite(LEDgreen, dark);        // green LED off
        analogWrite(LEDblue, brightness1c); 
        delay(p); 
        }    

Groupassignement: Power supply and measurement of the power consumption with the laboratory power supply device

Here you can find the datasheet of the DC bench power supply BK Precision model 1550 with 108 watt power supply (1-36 V and 0-3 A) from BK Precision.com which I used for powering my Atmega 328p board.

DC Bench
Here I will insert the Introduction for using it from the User Manual of the BK Precision:
"Using the 1550 switching mode power supply The unit is a Micro-controller based DC power supply with a total supply capability of 108W. By using a digital + / - keypad operation control, you can set the output voltage and current easily. It is a clean supply with quiet operation making it ideal for laboratory, work shop or educational applications where work bench space is limited. The 1550 has a USB charger output, constant current operation, tracking OVP, floating ground design, small footprint, output on/off push button and a small form factor."

"3.1 Ground Connection Depending on the application, the power supply output terminals can be grounded in any one of the following grounding conditions: Negative ground black (-) negative terminal is shorted with green GND terminal. Positive ground red (+) positive terminal is shorted with green GND terminal. Floating ground green terminal is not shorted with any of the output terminals. Remarks: When operating this power supply as a floating ground, high impedance leakage can exist between the power supply circuitry and the chassis ground."

When I connected the board with the three servos to the laboratory power supply, the following reading were to see:


The first image shows the power consumption of the servo start-up phase (the impulse phase is high: 5.1 V and 120 mA). Second image shows the power consumption of the low phase (5.1 V and 10 mA). Here was the servo just turned off (the phase of the pulse was over).

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