Data Conversion

Enter Your Electronics & Design Project for a chance to win a $200 shopping cart!

Submit an EntrySubmit an Entry  Back to homepage
Project14 Home
Monthly Themes
Monthly Theme Poll

 

I have made some progress with my combined servo tester and pulse generator project. I am happy with the servo tester part so I have decided to add an OLED display (128 x 64) and a button to select different modes. The Servo Tester will be the first mode and the second mode I want to add will be a pulse generator. At present I have not written the code for the Pulse Generator but I now have the display working and the button to change between modes.

 

The revised circuit diagram is show below. I have just added a push-to-make button on D3 for mode selection and a 128x64 OLED display (SDA on A4 and SCL on A5). An updated circuit diagram is shown below.

 

Updated Servo Tester Circuit Diagram

 

The display is Adafruit compatible so I just used their libraries. I have not used button inputs on my projects for a very long time so it was a challenge to get that working. Identifying how the debounce would work and then how to use it to select the mode. I now have an infinite while statement inside the main loop, which will just cycle sequentially through the modes available. At present there are only have two modes: Servo Tester and Pulse Generator, but it would be easy to add further modes, perhaps such as a DVM. The main loop part of the programme is listed below.

 

void loop(void)

{

 

int width;

int freq;

int modeselect;

int newmode;

 

width = 0;

freq = 0;

modeselect = 1; // Servo tester

newmode = 1;    // Used to read button

 

Serial.println("Servo Motor Tester " );

Serial.println("Dubbie Dubbie : Just for Fun " );

Serial.println(" 5th Feb'21 ");

Serial.println();

 

  display.clearDisplay();  // Clear the display so we can refresh

  display.setCursor(0,10);  // Bottom left

  display.println("Dubbie Dubbie ");

  display.println("Combined ");

  display.println("Servo Tester and ");

  display.println("Pulse Generator ");

  display.display();  // This outputs to the screen

 

  delay(1500);

  digitalWrite(ledblue, HIGH);   // Shows it's working

  delay(500);

  digitalWrite(ledblue, LOW);  

 

while(1)

  {

    servotestermode();

    pulsegeneratormode();

  } /* while */

} /* loop */

 

void mydisplaywidth(void)

 

{

int pulsevalue;

pulsevalue = 0;

  display.setCursor(80, 50); // Output the pulse width - bottom right

  display.fillRect(80, 50, 45, 8, 0); // Clear previous value

  pulsevalue = analogRead(adcwidth);

  display.setCursor(80, 50); // Output the pulse width - bottom right   

  display.print(pulsevalue);

  display.print(" us");

  display.display();

} /* mydisplaywidth */

 

bool buttonpress(int buttonselect)

 

{

int buttonvalue;

buttonvalue = 0;

 

  buttonvalue = digitalRead(buttonselect);

  if (buttonvalue > 0)

    {

      return(false);

    }

  else

    {

      do

        {

          delay(20); // 20 ms debounce delay  // press debounce

        } while (digitalRead(buttonselect) < 1);

      do

        {

          delay(20); //20 ms debounce delay  // release debounce

        } while (digitalRead(buttonselect) < 1);

      return(true);

    } /* if */

} /* buttonpress */

 

void servotestermode(void)

 

{

int pwidth;

pwidth = 0;

 

  display.clearDisplay();  // Clear the display so we can refresh

  display.setCursor(0,50);  // Bottom left

  display.println("Servo Tester ");

  while (!buttonpress(button))

    {

      digitalWrite(testservo, HIGH);

      delayMicroseconds(200);       // Start of the 1 ms pulse

      delayMicroseconds(pwidth);     // Makes up the rest of the pulse

      digitalWrite(testservo, LOW);

      Serial.println(pwidth);

      pwidth = analogRead(adcwidth); //Assumes 100 us conversion time

      pwidth = pwidth * 2;

      mydisplaywidth();

      delay(18); // The rest of the pulse   

    } /* while */

} /* servotestermode */

 

void pulsegeneratormode(void)

 

{

  while (!buttonpress(button))

    {

      display.clearDisplay();  // Clear the display so we can refresh

      display.setCursor(0,25);  // Middle left

      display.println("Pulse Generator ");

      display.display();  // This outputs to the screen          

    } /* while */ 

}

 

After spending a couple of days trying to get the push button and debounce to work I was pleased when it all came together this morning, as illustrated in the following video.

 

 

All I have to do now is write the code for the pulse generator and if time permits, create some sort of 3D printed box, or possibly buy a case.

 

Dubbie