In this lesson we show how to track items in OpenCV based on color using the HSV color space. Below is the code we developed in this lesson.

import cv2
print(cv2.__version__)
import numpy as np

def nothing(x):
    pass

cv2.namedWindow('Trackbars')
cv2.moveWindow('Trackbars',1320,0)

cv2.createTrackbar('hueLower', 'Trackbars',50,179,nothing)
cv2.createTrackbar('hueUpper', 'Trackbars',100,179,nothing)

cv2.createTrackbar('hue2Lower', 'Trackbars',50,179,nothing)
cv2.createTrackbar('hue2Upper', 'Trackbars',100,179,nothing)

cv2.createTrackbar('satLow', 'Trackbars',100,255,nothing)
cv2.createTrackbar('satHigh', 'Trackbars',255,255,nothing)
cv2.createTrackbar('valLow','Trackbars',100,255,nothing)
cv2.createTrackbar('valHigh','Trackbars',255,255,nothing)


dispW=640
dispH=480
flip=2
#Uncomment These next Two Line for Pi Camera
camSet='nvarguscamerasrc !  video/x-raw(memory:NVMM), width=3264, height=2464, format=NV12, framerate=21/1 ! nvvidconv flip-method='+str(flip)+' ! video/x-raw, width='+str(dispW)+', height='+str(dispH)+', format=BGRx ! videoconvert ! video/x-raw, format=BGR ! appsink'
cam= cv2.VideoCapture(camSet)

#Or, if you have a WEB cam, uncomment the next line
#(If it does not work, try setting to '1' instead of '0')
#cam=cv2.VideoCapture(0)
while True:
    ret, frame = cam.read()
    #frame=cv2.imread('smarties.png')
    cv2.imshow('nanoCam',frame)
    cv2.moveWindow('nanoCam',0,0)

    hsv=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)

    hueLow=cv2.getTrackbarPos('hueLower', 'Trackbars')
    hueUp=cv2.getTrackbarPos('hueUpper', 'Trackbars')

    hue2Low=cv2.getTrackbarPos('hue2Lower', 'Trackbars')
    hue2Up=cv2.getTrackbarPos('hue2Upper', 'Trackbars')

    Ls=cv2.getTrackbarPos('satLow', 'Trackbars')
    Us=cv2.getTrackbarPos('satHigh', 'Trackbars')

    Lv=cv2.getTrackbarPos('valLow', 'Trackbars')
    Uv=cv2.getTrackbarPos('valHigh', 'Trackbars')

    l_b=np.array([hueLow,Ls,Lv])
    u_b=np.array([hueUp,Us,Uv])

    l_b2=np.array([hue2Low,Ls,Lv])
    u_b2=np.array([hue2Up,Us,Uv])

    FGmask=cv2.inRange(hsv,l_b,u_b)
    FGmask2=cv2.inRange(hsv,l_b2,u_b2)
    FGmaskComp=cv2.add(FGmask,FGmask2)
    cv2.imshow('FGmaskComp',FGmaskComp)
    cv2.moveWindow('FGmaskComp',0,530)

    FG=cv2.bitwise_and(frame, frame, mask=FGmaskComp)
    cv2.imshow('FG',FG)
    cv2.moveWindow('FG',700,0)

    bgMask=cv2.bitwise_not(FGmaskComp)
    cv2.imshow('bgMask',bgMask)
    cv2.moveWindow('bgMask',700,530)

    BG=cv2.cvtColor(bgMask,cv2.COLOR_GRAY2BGR)

    final=cv2.add(FG,BG)
    cv2.imshow('final',final)
    cv2.moveWindow('final',1400,0)

    if cv2.waitKey(1)==ord('q'):
        break
cam.release()
cv2.destroyAllWindows()

import cv2

print(cv2.__version__)

import numpy as np

def nothing(x):

pass

cv2.namedWindow('Trackbars')

cv2.moveWindow('Trackbars',1320,0)

cv2.createTrackbar('hueLower', 'Trackbars',50,179,nothing)

cv2.createTrackbar('hueUpper', 'Trackbars',100,179,nothing)

cv2.createTrackbar('hue2Lower', 'Trackbars',50,179,nothing)

cv2.createTrackbar('hue2Upper', 'Trackbars',100,179,nothing)

cv2.createTrackbar('satLow', 'Trackbars',100,255,nothing)

cv2.createTrackbar('satHigh', 'Trackbars',255,255,nothing)

cv2.createTrackbar('valLow','Trackbars',100,255,nothing)

cv2.createTrackbar('valHigh','Trackbars',255,255,nothing)

dispW=640

dispH=480

flip=2

#Uncomment These next Two Line for Pi Camera

camSet='nvarguscamerasrc ! video/x-raw(memory:NVMM), width=3264, height=2464, format=NV12, framerate=21/1 ! nvvidconv flip-method='+str(flip)+' ! video/x-raw, width='+str(dispW)+', height='+str(dispH)+', format=BGRx ! videoconvert ! video/x-raw, format=BGR ! appsink'

cam= cv2.VideoCapture(camSet)

#Or, if you have a WEB cam, uncomment the next line

#(If it does not work, try setting to '1' instead of '0')

#cam=cv2.VideoCapture(0)

while True:

ret, frame = cam.read()

#frame=cv2.imread('smarties.png')

cv2.imshow('nanoCam',frame)

cv2.moveWindow('nanoCam',0,0)

hsv=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)

hueLow=cv2.getTrackbarPos('hueLower', 'Trackbars')

hueUp=cv2.getTrackbarPos('hueUpper', 'Trackbars')

hue2Low=cv2.getTrackbarPos('hue2Lower', 'Trackbars')

hue2Up=cv2.getTrackbarPos('hue2Upper', 'Trackbars')

Ls=cv2.getTrackbarPos('satLow', 'Trackbars')

Us=cv2.getTrackbarPos('satHigh', 'Trackbars')

Lv=cv2.getTrackbarPos('valLow', 'Trackbars')

Uv=cv2.getTrackbarPos('valHigh', 'Trackbars')

l_b=np.array([hueLow,Ls,Lv])

u_b=np.array([hueUp,Us,Uv])

l_b2=np.array([hue2Low,Ls,Lv])

u_b2=np.array([hue2Up,Us,Uv])

FGmask=cv2.inRange(hsv,l_b,u_b)

FGmask2=cv2.inRange(hsv,l_b2,u_b2)

FGmaskComp=cv2.add(FGmask,FGmask2)

cv2.imshow('FGmaskComp',FGmaskComp)

cv2.moveWindow('FGmaskComp',0,530)

FG=cv2.bitwise_and(frame, frame, mask=FGmaskComp)

cv2.imshow('FG',FG)

cv2.moveWindow('FG',700,0)

bgMask=cv2.bitwise_not(FGmaskComp)

cv2.imshow('bgMask',bgMask)

cv2.moveWindow('bgMask',700,530)

BG=cv2.cvtColor(bgMask,cv2.COLOR_GRAY2BGR)

final=cv2.add(FG,BG)

cv2.imshow('final',final)

cv2.moveWindow('final',1400,0)

if cv2.waitKey(1)==ord('q'):

break

cam.release()

cv2.destroyAllWindows()

Arduino, Tutorial

Arduino Tutorial 50: How to Connect and Use the DHT11 Temperature and Humidity Sensor

February 25, 2020 admin

In this lesson we show how to measure Temperature and Humidityusing the DHT11 sensor. This is a relatively simple sensor to use, but you will have to download and install a library. In our earlier lessons, we have used libraries before, but this is the first time you will have to download a library. The library I used was downloaded from HERE. The video explains in detail how to install the library, but in a nutshell you download the library from clicking the link on that page. Then you need to open the downloaded zip file, and then drag and drop the contents of the zip file to your desktop. Next you must determine where your arduino library folder is. You can do that by going to the arduino IDE, and under “file” select preferences. This will show you your “Sketchbook Location”, and that folder will contain your libraries folder. The folder you dragged and dropped onto your desktop should be dragged and dropped now into this library folder. The video shows you how to do this if this description is not clear. Now you will need to connect the sensor, according to this schematic:

The video develops the code to use this sensor step-by-step, but the code is included below for your convenience.

#include "DHT.h"
#define Type DHT11
int sensePin=2;
DHT HT(sensePin,Type);
float humidity;
float tempC;
float tempF;
int setTime=500;
int dt=1000;

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
HT.begin();
delay(setTime);
}

void loop() {
humidity=HT.readHumidity();
tempC=HT.readTemperature();
tempF=HT.readTemperature(true);

Serial.print("Humidity: ");
Serial.print(humidity);
Serial.print("% Temperature ");
Serial.print(tempC);
Serial.print(" C ");
Serial.print(tempF);
Serial.println(" F ");
delay(dt);


}

#include "DHT.h"

#define Type DHT11

int sensePin=2;

DHT HT(sensePin,Type);

float humidity;

float tempC;

float tempF;

int setTime=500;

int dt=1000;

void setup() {

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

Serial.begin(9600);

HT.begin();

delay(setTime);

}

void loop() {

humidity=HT.readHumidity();

tempC=HT.readTemperature();

tempF=HT.readTemperature(true);

Serial.print("Humidity: ");

Serial.print(humidity);

Serial.print("% Temperature ");

Serial.print(tempC);

Serial.print(" C ");

Serial.print(tempF);

Serial.println(" F ");

delay(dt);

}

Arduino, Tutorial

Arduino Tutorial 49: How to Build a Simple Calculator with LCD Display

February 18, 2020 admin

In this lesson we show you our solution to the assignment in Lesson 48 to build a simple calculator with an LCD Output. The video steps you through the project build step-by-step.

In the project, the following schematic is used.

Arduino LCD Schematic — This schematic will allow you to connect the LCD to the Arduino.

If you need the kit we are using in this series of lessons, you can get it HERE.

And this is the code developed in the video.

#include <LiquidCrystal.h>
int rs=7;
int en=8;
int d4=9;
int d5=10;
int d6=11;
int d7=12;

float firstNum;
float secNum;
float answer;

String op;

LiquidCrystal lcd(rs,en,d4,d5,d6,d7);
void setup() {
  // put your setup code here, to run once:
lcd.begin(16,2);
Serial.begin(9600);
}

void loop() {
lcd.setCursor(0,0);
lcd.print("Input 1st Number");
while (Serial.available()==0){
  
}
firstNum=Serial.parseFloat();
lcd.clear();
lcd.setCursor(0,0);
lcd.print("Input 2nd Number");
while (Serial.available()==0){
}
secNum=Serial.parseFloat();

lcd.clear();
lcd.setCursor(0,0);
lcd.print("Input(+,-,*,/)");
while (Serial.available()==0){
  
}
op=Serial.readString();

if (op=="+"){
  answer=firstNum+secNum;
}
if (op=="-"){
  answer=firstNum-secNum;
}
if (op=="*"){
  answer=firstNum*secNum;
}
if (op=="/") {
  answer=firstNum/secNum;
}
lcd.clear();
lcd.setCursor(0,0);
lcd.print(firstNum);
lcd.print(op);
lcd.print(secNum);
lcd.print(" = ");
lcd.print(answer);
lcd.setCursor(0,1);
lcd.print("Thank You");
delay(5000);
lcd.clear();
}

#include <LiquidCrystal.h>

int rs=7;

int en=8;

int d4=9;

int d5=10;

int d6=11;

int d7=12;

float firstNum;

float secNum;

float answer;

String op;

LiquidCrystal lcd(rs,en,d4,d5,d6,d7);

void setup() {

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

lcd.begin(16,2);

Serial.begin(9600);

}

void loop() {

lcd.setCursor(0,0);

lcd.print("Input 1st Number");

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

}

firstNum=Serial.parseFloat();

lcd.clear();

lcd.setCursor(0,0);

lcd.print("Input 2nd Number");

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

}

secNum=Serial.parseFloat();

lcd.clear();

lcd.setCursor(0,0);

lcd.print("Input(+,-,*,/)");

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

}

op=Serial.readString();

if (op=="+"){

answer=firstNum+secNum;

}

if (op=="-"){

answer=firstNum-secNum;

}

if (op=="*"){

answer=firstNum*secNum;

}

if (op=="/") {

answer=firstNum/secNum;

}

lcd.clear();

lcd.setCursor(0,0);

lcd.print(firstNum);

lcd.print(op);

lcd.print(secNum);

lcd.print(" = ");

lcd.print(answer);

lcd.setCursor(0,1);

lcd.print("Thank You");

delay(5000);

lcd.clear();

}

Arduino, Tutorial

Arduino Tutorial 48: Connecting and Using an LCD Display

February 11, 2020 admin

LCD Arduino — LCD connected to an Arduino.

It is often times useful to “un-tether” your arduino from your desktop PC, in order to have a system you can walk around with, and interact with the real world. One of the first steps in making this happen is to have some sort of display on your arduino project. In this lesson, we show you how to connect and program your project to be able to display simple messages on the LCD. This is a schematic diagram of how to connect the arduino to an LCD display. This will work for the LCD in the Elegoo Kit. Many LCD displays in fact share this same connection schematic.

The details are provided in the following video.

Below is the code we developed in the video.

#include <LiquidCrystal.h>
int rs=7;
int en=8;
int d4=9;
int d5=10;
int d6=11;
int d7=12;
LiquidCrystal lcd(rs,en,d4,d5,d6,d7);
void setup() {
  // put your setup code here, to run once:
lcd.begin(16,2);
}

void loop() {
lcd.setCursor(0,0);
lcd.print("Watch me Count");
for (int j=1;j<=10;j=j+1){
  lcd.setCursor(0,1);
  lcd.print(j);
  delay(500);
 
}
 lcd.clear();
}

#include <LiquidCrystal.h>

int rs=7;

int en=8;

int d4=9;

int d5=10;

int d6=11;

int d7=12;

LiquidCrystal lcd(rs,en,d4,d5,d6,d7);

void setup() {

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

lcd.begin(16,2);

}

void loop() {

lcd.setCursor(0,0);

lcd.print("Watch me Count");

for (int j=1;j<=10;j=j+1){

lcd.setCursor(0,1);

lcd.print(j);

delay(500);

}

lcd.clear();

}

Arduino 9-Axis IMU Totorials

9-Axis IMU LESSON 26: Understanding PID Control systems with Arduino

February 6, 2020 admin

In this lesson we use our BNO055 9-axis sensor, and our pan-tilt servo mount to create a self-leveling platform based on a classic PID control system. The video takes you step by step through the theory behind a PID controller, and then demonstrates a practical example in hardware. In the video we develop the code below.

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BNO055.h>
#include <utility/imumaths.h>
#include <math.h>
#include <Servo.h>

Servo pitchServo;
Servo rollServo;

float q0;
float q1;
float q2;
float q3;

float k1=.5;
float k2=55;
float k3=.00001;

int milliOld;
int milliNew;
int dt;

float rollTarget=0;
float rollActual;
float rollError=0;
float rollErrorOld;
float rollErrorChange;
float rollErrorSlope=0;
float rollErrorArea=0;
float rollServoVal=90;

float pitchTarget=0;
float pitchActual;
float pitchError=0;
float pitchErrorOld;
float pitchErrorChange;
float pitchErrorSlope=0;
float pitchErrorArea=0;
float pitchServoVal=90;

#define BNO055_SAMPLERATE_DELAY_MS (100)

Adafruit_BNO055 myIMU = Adafruit_BNO055();

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
myIMU.begin();
delay(1000);
int8_t temp=myIMU.getTemp();
myIMU.setExtCrystalUse(true);
rollServo.attach(2);
pitchServo.attach(3);

rollServo.write(rollServoVal);
delay(20);
pitchServo.write(pitchServoVal);
delay(20);

milliNew=millis();
}

void loop() {
  // put your main code here, to run repeatedly:
uint8_t system, gyro, accel, mg = 0;
myIMU.getCalibration(&system, &gyro, &accel, &mg);

imu::Quaternion quat=myIMU.getQuat();

q0=quat.w();
q1=quat.x();
q2=quat.y();
q3=quat.z();

rollActual=atan2(2*(q0*q1+q2*q3),1-2*(q1*q1+q2*q2));
pitchActual=asin(2*(q0*q2-q3*q1));

rollActual=rollActual/(2*3.141592654)*360;
pitchActual=pitchActual/(2*3.141592654)*360;

milliOld=milliNew;
milliNew=millis();
dt=milliNew-milliOld;

rollErrorOld=rollError;
rollError=rollTarget-rollActual;
rollErrorChange=rollError-rollErrorOld;
rollErrorSlope=rollErrorChange/dt;
rollErrorArea=rollErrorArea+rollError*dt;

pitchErrorOld=pitchError;
pitchError=pitchTarget-pitchActual;
pitchErrorChange=pitchError-pitchErrorOld;
pitchErrorSlope=pitchErrorChange/dt;
pitchErrorArea=pitchErrorArea+pitchError*dt;

rollServoVal=rollServoVal+k1*rollError+k2*rollErrorSlope+k3*rollErrorArea;
rollServo.write(rollServoVal);

pitchServoVal=pitchServoVal+k1*pitchError+k2*pitchErrorSlope+k3*pitchErrorArea;
pitchServo.write(pitchServoVal);

Serial.print(rollTarget);
Serial.print(",");
Serial.print(rollActual);
Serial.print(",");
Serial.print(pitchTarget);
Serial.print(",");
Serial.print(pitchActual);
Serial.print(",");
Serial.print(accel);
Serial.print(",");
Serial.print(gyro);
Serial.print(",");
Serial.print(mg);
Serial.print(",");
Serial.println(system);

delay(BNO055_SAMPLERATE_DELAY_MS);
}

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#include <Wire.h>

#include <Adafruit_Sensor.h>

#include <Adafruit_BNO055.h>

#include <utility/imumaths.h>

#include <math.h>

#include <Servo.h>

Servo pitchServo;

Servo rollServo;

float q0;

float q1;

float q2;

float q3;

float k1=.5;

float k2=55;

float k3=.00001;

int milliOld;

int milliNew;

int dt;

float rollTarget=0;

float rollActual;

float rollError=0;

float rollErrorOld;

float rollErrorChange;

float rollErrorSlope=0;

float rollErrorArea=0;

float rollServoVal=90;

float pitchTarget=0;

float pitchActual;

float pitchError=0;

float pitchErrorOld;

float pitchErrorChange;

float pitchErrorSlope=0;

float pitchErrorArea=0;

float pitchServoVal=90;

#define BNO055_SAMPLERATE_DELAY_MS (100)

Adafruit_BNO055 myIMU = Adafruit_BNO055();

void setup() {

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

Serial.begin(115200);

myIMU.begin();

delay(1000);

int8_t temp=myIMU.getTemp();

myIMU.setExtCrystalUse(true);

rollServo.attach(2);

pitchServo.attach(3);

rollServo.write(rollServoVal);

delay(20);

pitchServo.write(pitchServoVal);

delay(20);

milliNew=millis();

}

void loop() {

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

uint8_t system, gyro, accel, mg = 0;

myIMU.getCalibration(&system, &gyro, &accel, &mg);

imu::Quaternion quat=myIMU.getQuat();

q0=quat.w();

q1=quat.x();

q2=quat.y();

q3=quat.z();

rollActual=atan2(2*(q0*q1+q2*q3),1-2*(q1*q1+q2*q2));

pitchActual=asin(2*(q0*q2-q3*q1));

rollActual=rollActual/(2*3.141592654)*360;

pitchActual=pitchActual/(2*3.141592654)*360;

milliOld=milliNew;

milliNew=millis();

dt=milliNew-milliOld;

rollErrorOld=rollError;

rollError=rollTarget-rollActual;

rollErrorChange=rollError-rollErrorOld;

rollErrorSlope=rollErrorChange/dt;

rollErrorArea=rollErrorArea+rollError*dt;

pitchErrorOld=pitchError;

pitchError=pitchTarget-pitchActual;

pitchErrorChange=pitchError-pitchErrorOld;

pitchErrorSlope=pitchErrorChange/dt;

pitchErrorArea=pitchErrorArea+pitchError*dt;

rollServoVal=rollServoVal+k1*rollError+k2*rollErrorSlope+k3*rollErrorArea;

rollServo.write(rollServoVal);

pitchServoVal=pitchServoVal+k1*pitchError+k2*pitchErrorSlope+k3*pitchErrorArea;

pitchServo.write(pitchServoVal);

Serial.print(rollTarget);

Serial.print(",");

Serial.print(rollActual);

Serial.print(",");

Serial.print(pitchTarget);

Serial.print(",");

Serial.print(pitchActual);

Serial.print(",");

Serial.print(accel);

Serial.print(",");

Serial.print(gyro);

Serial.print(",");

Serial.print(mg);

Serial.print(",");

Serial.println(system);

delay(BNO055_SAMPLERATE_DELAY_MS);

}

Technology Tutorials

Monthly Archives: February 2020

AI on the Jetson Nano LESSON 27: Tracking Objects in OpenCV Using HSV Color Space

Arduino Tutorial 50: How to Connect and Use the DHT11 Temperature and Humidity Sensor

Arduino Tutorial 49: How to Build a Simple Calculator with LCD Display

Arduino Tutorial 48: Connecting and Using an LCD Display

9-Axis IMU LESSON 26: Understanding PID Control systems with Arduino

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