In this video lesson we show how you can use the Raspberry Pi Pico PIO State Machine to sweep a servo through its full range of motion. The video will take you through things step-by-step. For your convenience the code developed in the video is included below. Enjoy!

import time
from machine import Pin
import rp2
@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW,out_shiftdir=rp2.PIO.SHIFT_RIGHT)
def servoSet():
    wrap_target()
    mov(x,osr)
    mov(y,isr)
    set(pins,0)
    label('timeLoop')
    jmp(x_not_y,'nxt')
    set(pins,1)
    label('nxt')
    jmp(y_dec,'timeLoop')    
    wrap()  
sm0 = rp2.StateMachine(0,servoSet, freq=2000000, set_base=Pin(20))
sm0.active(1)
sm0.put(20000)
sm0.exec("pull()")
sm0.exec("mov(isr,osr)")
while True:
    for angle in range(0,180,1):
        pw=int(500+angle*2000/180)
        sm0.put(pw)
        sm0.exec("pull()")
    time.sleep(5)
    for angle in range(180,0,-1):
        pw=int(500+angle*2000/180)
        sm0.put(pw)
        sm0.exec("pull()")

import time

from machine import Pin

import rp2

@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW,out_shiftdir=rp2.PIO.SHIFT_RIGHT)

def servoSet():

wrap_target()

mov(x,osr)

mov(y,isr)

set(pins,0)

label('timeLoop')

jmp(x_not_y,'nxt')

set(pins,1)

label('nxt')

jmp(y_dec,'timeLoop')

wrap()

sm0 = rp2.StateMachine(0,servoSet, freq=2000000, set_base=Pin(20))

sm0.active(1)

sm0.put(20000)

sm0.exec("pull()")

sm0.exec("mov(isr,osr)")

while True:

for angle in range(0,180,1):

pw=int(500+angle*2000/180)

sm0.put(pw)

sm0.exec("pull()")

time.sleep(5)

for angle in range(180,0,-1):

pw=int(500+angle*2000/180)

sm0.put(pw)

sm0.exec("pull()")

MicroPython, Raspberry Pi Pico

Control Servo Position Using a Raspberry Pi Pico PIO State Machine

December 3, 2024 admin

In this video tutorial we show you how you can use a Raspberry Pi Pico PIO Statemachine to control the position of a servo. For your convenience, the code from this lesson is presented below. Enjoy!

from machine import Pin
import rp2
@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW,out_shiftdir=rp2.PIO.SHIFT_RIGHT)
def servoSet():
    set(x,0b11111)
    in_(x,5)
    set(x,0b0100)
    in_(x,4)
    #set(x,0b00000)
    #in_(x,1)
    mov(osr,isr)
    
    mov(isr,null)
    set(y,0b10011)
    in_(y,5)
    set(y,0b10001)
    in_(y,5)
    set(y,0b00000)
    in_(y,5)
    
    wrap_target()
    mov(x,osr)
    mov(y,isr)
    set(pins,0)
    label('timeLoop')
    jmp(x_not_y,'nxt')
    set(pins,1)
    label('nxt')
    jmp(y_dec,'timeLoop')    
    wrap()
    
sm0 = rp2.StateMachine(0,servoSet, freq=2000000, set_base=Pin(20))
sm0.active(1)

from machine import Pin

import rp2

@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW,out_shiftdir=rp2.PIO.SHIFT_RIGHT)

def servoSet():

set(x,0b11111)

in_(x,5)

set(x,0b0100)

in_(x,4)

#set(x,0b00000)

#in_(x,1)

mov(osr,isr)

mov(isr,null)

set(y,0b10011)

in_(y,5)

set(y,0b10001)

in_(y,5)

set(y,0b00000)

in_(y,5)

wrap_target()

mov(x,osr)

mov(y,isr)

set(pins,0)

label('timeLoop')

jmp(x_not_y,'nxt')

set(pins,1)

label('nxt')

jmp(y_dec,'timeLoop')

wrap()

sm0 = rp2.StateMachine(0,servoSet, freq=2000000, set_base=Pin(20))

sm0.active(1)

Arduino

Scan Arduino to Find I2C Addresses

November 26, 2024 admin

A challenge in many Arduino projects is that it can be difficult to get I2C components working properly. Many times the libraries and demonstration code indicate a certain I2C address for the component, but the Arduino is unable to find the component at that Address. This can be a challenge, because often times we might not have the exact same version of the component that is assumed in the libraries and code. A perfect example of this are the SSD1306 OLED displays. Many of the components look identical, but they can have different I2C addresses. In order to overcome this challenge, the following code allows you to scan your I2C Bus, and list the address of all the components found. Simply attach the component as instructed in the component documentation. Then run the following code. It will list the address of the I2C components it finds. Then you can edit the sample code to use the proper address. Enjoy!

#include <Wire.h>
#define myWire Wire
int numDevices;
byte error, address;
void setup() {
  myWire.begin();
  Serial.begin(9600);
  Serial.println("Find I2C Devices: ");
}
void loop() {
  Serial.println("Scanning...");
  numDevices = 0;
  for (address = 1; address < 127; address=address+1) {
    myWire.beginTransmission(address);
    error = myWire.endTransmission();
    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.print(address, HEX);
      Serial.println("  !");
      numDevices = numDevices + 1;
    } else if (error == 4) {
      Serial.print("Unknown error at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.println(address, HEX);
    }
  }
  if (numDevices == 0)
    Serial.println("No I2C devices found");
  delay(5000);  
}

#include <Wire.h>

#define myWire Wire

int numDevices;

byte error, address;

void setup() {

myWire.begin();

Serial.begin(9600);

Serial.println("Find I2C Devices: ");

}

void loop() {

Serial.println("Scanning...");

numDevices = 0;

for (address = 1; address < 127; address=address+1) {

myWire.beginTransmission(address);

error = myWire.endTransmission();

if (error == 0) {

Serial.print("I2C device found at address 0x");

if (address < 16)

Serial.print("0");

Serial.print(address, HEX);

Serial.println(" !");

numDevices = numDevices + 1;

} else if (error == 4) {

Serial.print("Unknown error at address 0x");

if (address < 16)

Serial.print("0");

Serial.println(address, HEX);

}

if (numDevices == 0)

Serial.println("No I2C devices found");

delay(5000);

}

Arduino

Arduino Tone Frequencies to Produce Specific Musical Notes

November 16, 2024 admin

The arduino connected to a passive buzzer can actually be used to create simple music. In order to do this, we need to know the frequencies associated with specific notes. The code below can be used to directly write musical notes to the arduino tone command. This will be covered in an upcoming lesson. Enjoy!

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978

#define NOTE_B0 31

#define NOTE_C1 33

#define NOTE_CS1 35

#define NOTE_D1 37

#define NOTE_DS1 39

#define NOTE_E1 41

#define NOTE_F1 44

#define NOTE_FS1 46

#define NOTE_G1 49

#define NOTE_GS1 52

#define NOTE_A1 55

#define NOTE_AS1 58

#define NOTE_B1 62

#define NOTE_C2 65

#define NOTE_CS2 69

#define NOTE_D2 73

#define NOTE_DS2 78

#define NOTE_E2 82

#define NOTE_F2 87

#define NOTE_FS2 93

#define NOTE_G2 98

#define NOTE_GS2 104

#define NOTE_A2 110

#define NOTE_AS2 117

#define NOTE_B2 123

#define NOTE_C3 131

#define NOTE_CS3 139

#define NOTE_D3 147

#define NOTE_DS3 156

#define NOTE_E3 165

#define NOTE_F3 175

#define NOTE_FS3 185

#define NOTE_G3 196

#define NOTE_GS3 208

#define NOTE_A3 220

#define NOTE_AS3 233

#define NOTE_B3 247

#define NOTE_C4 262

#define NOTE_CS4 277

#define NOTE_D4 294

#define NOTE_DS4 311

#define NOTE_E4 330

#define NOTE_F4 349

#define NOTE_FS4 370

#define NOTE_G4 392

#define NOTE_GS4 415

#define NOTE_A4 440

#define NOTE_AS4 466

#define NOTE_B4 494

#define NOTE_C5 523

#define NOTE_CS5 554

#define NOTE_D5 587

#define NOTE_DS5 622

#define NOTE_E5 659

#define NOTE_F5 698

#define NOTE_FS5 740

#define NOTE_G5 784

#define NOTE_GS5 831

#define NOTE_A5 880

#define NOTE_AS5 932

#define NOTE_B5 988

#define NOTE_C6 1047

#define NOTE_CS6 1109

#define NOTE_D6 1175

#define NOTE_DS6 1245

#define NOTE_E6 1319

#define NOTE_F6 1397

#define NOTE_FS6 1480

#define NOTE_G6 1568

#define NOTE_GS6 1661

#define NOTE_A6 1760

#define NOTE_AS6 1865

#define NOTE_B6 1976

#define NOTE_C7 2093

#define NOTE_CS7 2217

#define NOTE_D7 2349

#define NOTE_DS7 2489

#define NOTE_E7 2637

#define NOTE_F7 2794

#define NOTE_FS7 2960

#define NOTE_G7 3136

#define NOTE_GS7 3322

#define NOTE_A7 3520

#define NOTE_AS7 3729

#define NOTE_B7 3951

#define NOTE_C8 4186

#define NOTE_CS8 4435

#define NOTE_D8 4699

#define NOTE_DS8 4978

Arduino

Arduino Program to Average and Sort Grades

October 3, 2024 admin

In this video lesson we show how to create a program that will input a list of grades, sort them into descending order, average them, and then find the high and low grades. This is a classic first year college programming assignment. We take you through it step by step. For you convenience, we include the code below.

float grades[25];
int numGrades;
int i;
String myPrompt;

float tmp;
int j;
int flag = 1;

float bucket;
float avg;
float highGrade = 0;
float lowGrade = 100;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
}
void loop() {
  // put your main code here, to run repeatedly:
  Serial.println("How Many Grades? ");
  while (Serial.available() == 0) {
  }
  numGrades = Serial.parseInt();
  for (i = 0; i < numGrades; i = i + 1) {
    myPrompt = "Please Input Grade: " + String(i + 1);
    Serial.println(myPrompt);
    while (Serial.available() == 0) {
    }
    grades[i] = Serial.parseFloat();
  }
  // for (j = 0; j < numGrades - 1; j = j + 1) {
  //   for (i = 0; i < numGrades - 1 - j; i = i + 1) {
  //     if (grades[i] < grades[i + 1]) {
  //       tmp = grades[i];
  //       grades[i] = grades[i + 1];
  //       grades[i + 1] = tmp;
  //     }
  //   }
    flag=1;
    while (flag == 1) {
      flag = 0;
      for (i = 0; i < numGrades - 1; i = i + 1) {
        if (grades[i] < grades[i + 1]) {
          tmp = grades[i];
          grades[i] = grades[i + 1];
          grades[i + 1] = tmp;
          flag = 1;
        }
      }
    }
    Serial.println();
    Serial.println("Your Grades Are: ");
    for (i = 0; i < numGrades; i = i + 1) {
      Serial.println(grades[i]);
    }
    bucket = 0;
    for (i = 0; i < numGrades; i = i + 1) {
      bucket = bucket + grades[i];
    }
    avg = bucket / numGrades;
    Serial.println("Your Average is: " + String(avg));
    highGrade = 0;
    lowGrade = 100;
    for (i = 0; i < numGrades; i = i + 1) {
      if (grades[i] > highGrade) {
        highGrade = grades[i];
      }
      if (grades[i] < lowGrade) {
        lowGrade = grades[i];
      }
    }
    Serial.println("Your High Grade is: " + String(highGrade));
    Serial.println("Your Low Grade is: " + String(lowGrade));
    Serial.println();
  }

float grades[25];

int numGrades;

int i;

String myPrompt;

float tmp;

int j;

int flag = 1;

float bucket;

float avg;

float highGrade = 0;

float lowGrade = 100;

void setup() {

// put your setup code here, to run once:

Serial.begin(9600);

}

void loop() {

// put your main code here, to run repeatedly:

Serial.println("How Many Grades? ");

while (Serial.available() == 0) {

}

numGrades = Serial.parseInt();

for (i = 0; i < numGrades; i = i + 1) {

myPrompt = "Please Input Grade: " + String(i + 1);

Serial.println(myPrompt);

while (Serial.available() == 0) {

}

grades[i] = Serial.parseFloat();

}

// for (j = 0; j < numGrades - 1; j = j + 1) {

// for (i = 0; i < numGrades - 1 - j; i = i + 1) {

// if (grades[i] < grades[i + 1]) {

// tmp = grades[i];

// grades[i] = grades[i + 1];

// grades[i + 1] = tmp;

// }

flag=1;

while (flag == 1) {

flag = 0;

for (i = 0; i < numGrades - 1; i = i + 1) {

if (grades[i] < grades[i + 1]) {

tmp = grades[i];

grades[i] = grades[i + 1];

grades[i + 1] = tmp;

flag = 1;

}

Serial.println();

Serial.println("Your Grades Are: ");

for (i = 0; i < numGrades; i = i + 1) {

Serial.println(grades[i]);

}

bucket = 0;

for (i = 0; i < numGrades; i = i + 1) {

bucket = bucket + grades[i];

}

avg = bucket / numGrades;

Serial.println("Your Average is: " + String(avg));

highGrade = 0;

lowGrade = 100;

for (i = 0; i < numGrades; i = i + 1) {

if (grades[i] > highGrade) {

highGrade = grades[i];

}

if (grades[i] < lowGrade) {

lowGrade = grades[i];

}

Serial.println("Your High Grade is: " + String(highGrade));

Serial.println("Your Low Grade is: " + String(lowGrade));

Serial.println();

}

Technology Tutorials

Sweeping Servo Position Using the PIO State Machine on the Raspberry Pi Pico PIO State Machine

Control Servo Position Using a Raspberry Pi Pico PIO State Machine

Scan Arduino to Find I2C Addresses

Arduino Tone Frequencies to Produce Specific Musical Notes

Arduino Program to Average and Sort Grades

Making The World a Better Place One High Tech Project at a Time. Enjoy!