Jetson Xavier NX Lesson 7: Connecting and Controlling Servos

July 1, 2020 admin

In this lesson we show you how to control a pan/tilt camera bracket with the NVIDIA Jetson Xavier NX. We go through the physical build of the bracket, how to connect the circuit, and then how to program the servos. We use the Adafruit circuitpython library, and show how to download and use the library. If you want to play along at home, you can pick the pan/tilt bracket and servos up HERE, and you can grab a couple of Raspberry Pi cameras HERE.

Below is the simple code for moving the servo using the Jetson Xavier NX:

import time
from adafruit_servokit import ServoKit
kit=ServoKit(channels=16)
tilt=125
pan=0
kit.servo[0].angle=pan
kit.servo[1].angle=tilt
for i in range(0,180):
    kit.servo[0].angle=i
    time.sleep(.05)
for i in range(180,0,-1):
    kit.servo[0].angle=i
    time.sleep(.05)
for i in range(45,180):
    kit.servo[1].angle=i
    time.sleep(.05)
for i in range(180,0,-1):
    kit.servo[1].angle=i
    time.sleep(.05)

import time

from adafruit_servokit import ServoKit

kit=ServoKit(channels=16)

tilt=125

pan=0

kit.servo[0].angle=pan

kit.servo[1].angle=tilt

for i in range(0,180):

kit.servo[0].angle=i

time.sleep(.05)

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

kit.servo[0].angle=i

time.sleep(.05)

for i in range(45,180):

kit.servo[1].angle=i

time.sleep(.05)

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

kit.servo[1].angle=i

time.sleep(.05)

Arduino, Tutorial

ARDUINO TUTORIAL 68: Make a Remote Controlled RGB LED with Brightness and Color Control

June 30, 2020 admin

RGB LED Remote Control — This is our Remote Controlled RGB LED

In this lesson we take you through step-by-step instructions on creating a remotely controlled RGB LED. This is the solution to the Homework Assignment given in Tutorial 68. It is important for you to try and complete this on your own before looking at my solutions.

We are building this with parts from our Elegoo Kit , and our actual build is using an Arduino Nano, which allows the project to be built on a single breadboard. You can get the neat jumper wires HERE.

This video steps you through our build.

Below is the code we developed in this video.

#include <IRremote.h>
int IRpin=9;
IRrecv IR(IRpin);
decode_results cmd;
String myCom;

int rPin=6;
int gPin=10;
int bPin=5;

int rBright=255;
int gBright=255;
int bBright=255;

float dFact=1;


void setup()
{
Serial.begin(9600);
IR.enableIRIn();

pinMode(rPin,OUTPUT);
pinMode(gPin,OUTPUT);
pinMode(bPin,OUTPUT);

}

void loop() {
  while (IR.decode(&cmd)==0){ 
}
delay(1500);
IR.resume();

if (cmd.value==0xFF6897){
  myCom="zero";
  Serial.println(myCom); 
}
if (cmd.value==0xFF30CF){
  myCom="one";
  Serial.println(myCom); 
}
if (cmd.value==0xFF18E7){
  myCom="two";
  Serial.println(myCom); 
}
if (cmd.value==0xFF7A85){
  myCom="three";
  Serial.println(myCom); 
}
if (cmd.value==0xFF10EF){
  myCom="four";
  Serial.println(myCom); 
}
if (cmd.value==0xFF38C7){
  myCom="five";
  Serial.println(myCom); 
}
if (cmd.value==0xFF5AA5){
  myCom="six";
  Serial.println(myCom); 
}
if (cmd.value==0xFF42BD){
  myCom="seven";
  Serial.println(myCom); 
}
if (cmd.value==0xFF4AB5){
  myCom="eight";
  Serial.println(myCom); 
}
if (cmd.value==0xFF52AD){
  myCom="nine";
  Serial.println(myCom); 
}

if (cmd.value==0xFFA25D){
  myCom="pwr";
  Serial.println(myCom); 
}
if (cmd.value==0xFF629D){
  myCom="v+";
  Serial.println(myCom);
}
if (cmd.value==0xFFE21D){
  myCom="fun";
  Serial.println(myCom);
}
if (cmd.value==0xFF22DD){
  myCom="rew";
  Serial.println(myCom);
}
if (cmd.value==0xFF02FD){
  myCom="play";
  Serial.println(myCom);
}
if (cmd.value==0xFFC23D){
  myCom="ff";
  Serial.println(myCom);
}
if (cmd.value==0xFFE01F){
  myCom="dn";
  Serial.println(myCom);
}
if (cmd.value==0xFFA857){
  myCom="v-";
  Serial.println(myCom);
}
if (cmd.value==0xFF906F){
  myCom="up";
  Serial.println(myCom);
}
if (cmd.value==0xFF9867){
  myCom="eq";
  Serial.println(myCom);
}
if (cmd.value==0xFFB04F
){
  myCom="st";
  Serial.println(myCom);
}
if(myCom=="pwr"){
  rBright=255;
  gBright=255;
  bBright=255;
  dFact=1;
}

if(myCom=="fun"){
  rBright=0;
  gBright=0;
  bBright=0;
  dFact=0;
}
if(myCom=="zero"){
  rBright=255;
  gBright=255;
  bBright=255;
}
if(myCom=="one"){
  rBright=255;
  gBright=0;
  bBright=0;
}
if(myCom=="two"){
  rBright=0;
  gBright=255;
  bBright=0;
}
if(myCom=="three"){
  rBright=0;
  gBright=0;
  bBright=255;
}
if(myCom=="four"){
  rBright=0;
  gBright=255;
  bBright=255;
}
if(myCom=="five"){
  rBright=255;
  gBright=0;
  bBright=150;
}
if(myCom=="six"){
  rBright=255;
  gBright=255;
  bBright=0;
}
if (myCom=="dn"){
  dFact=dFact*.75;
}
if (myCom=="up"){
  dFact=dFact*1.3;
  if (dFact>1){
    dFact=1;
  }
}

analogWrite(rPin,rBright*dFact);
analogWrite(gPin,gBright*dFact);
analogWrite(bPin,bBright*dFact);
}

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#include <IRremote.h>

int IRpin=9;

IRrecv IR(IRpin);

decode_results cmd;

String myCom;

int rPin=6;

int gPin=10;

int bPin=5;

int rBright=255;

int gBright=255;

int bBright=255;

float dFact=1;

void setup()

{

Serial.begin(9600);

IR.enableIRIn();

pinMode(rPin,OUTPUT);

pinMode(gPin,OUTPUT);

pinMode(bPin,OUTPUT);

}

void loop() {

while (IR.decode(&cmd)==0){

}

delay(1500);

IR.resume();

if (cmd.value==0xFF6897){

myCom="zero";

Serial.println(myCom);

}

if (cmd.value==0xFF30CF){

myCom="one";

Serial.println(myCom);

}

if (cmd.value==0xFF18E7){

myCom="two";

Serial.println(myCom);

}

if (cmd.value==0xFF7A85){

myCom="three";

Serial.println(myCom);

}

if (cmd.value==0xFF10EF){

myCom="four";

Serial.println(myCom);

}

if (cmd.value==0xFF38C7){

myCom="five";

Serial.println(myCom);

}

if (cmd.value==0xFF5AA5){

myCom="six";

Serial.println(myCom);

}

if (cmd.value==0xFF42BD){

myCom="seven";

Serial.println(myCom);

}

if (cmd.value==0xFF4AB5){

myCom="eight";

Serial.println(myCom);

}

if (cmd.value==0xFF52AD){

myCom="nine";

Serial.println(myCom);

}

if (cmd.value==0xFFA25D){

myCom="pwr";

Serial.println(myCom);

}

if (cmd.value==0xFF629D){

myCom="v+";

Serial.println(myCom);

}

if (cmd.value==0xFFE21D){

myCom="fun";

Serial.println(myCom);

}

if (cmd.value==0xFF22DD){

myCom="rew";

Serial.println(myCom);

}

if (cmd.value==0xFF02FD){

myCom="play";

Serial.println(myCom);

}

if (cmd.value==0xFFC23D){

myCom="ff";

Serial.println(myCom);

}

if (cmd.value==0xFFE01F){

myCom="dn";

Serial.println(myCom);

}

if (cmd.value==0xFFA857){

myCom="v-";

Serial.println(myCom);

}

if (cmd.value==0xFF906F){

myCom="up";

Serial.println(myCom);

}

if (cmd.value==0xFF9867){

myCom="eq";

Serial.println(myCom);

}

if (cmd.value==0xFFB04F

){

myCom="st";

Serial.println(myCom);

}

if(myCom=="pwr"){

rBright=255;

gBright=255;

bBright=255;

dFact=1;

}

if(myCom=="fun"){

rBright=0;

gBright=0;

bBright=0;

dFact=0;

}

if(myCom=="zero"){

rBright=255;

gBright=255;

bBright=255;

}

if(myCom=="one"){

rBright=255;

gBright=0;

bBright=0;

}

if(myCom=="two"){

rBright=0;

gBright=255;

bBright=0;

}

if(myCom=="three"){

rBright=0;

gBright=0;

bBright=255;

}

if(myCom=="four"){

rBright=0;

gBright=255;

bBright=255;

}

if(myCom=="five"){

rBright=255;

gBright=0;

bBright=150;

}

if(myCom=="six"){

rBright=255;

gBright=255;

bBright=0;

}

if (myCom=="dn"){

dFact=dFact*.75;

}

if (myCom=="up"){

dFact=dFact*1.3;

if (dFact>1){

dFact=1;

}

analogWrite(rPin,rBright*dFact);

analogWrite(gPin,gBright*dFact);

analogWrite(bPin,bBright*dFact);

}

Jetson Xavier NX

Jetson Xavier NX Lesson 6: Camera Gear and Setup for Future Lessons

June 24, 2020 admin

In this lesson we discuss the future direction of this series, and the gear needed to move forward.

Moving forward, I will be running two pan/tilt servos for the raspberry pi cameras. I suggest buying the same gear HERE. I suggest purchasing two units.

Then, we also need two Version two raspberry pi cameras. I like the following ones, because they include a neat little acrylic case, and the long cable, which makes it work much better on the pan/tilt bracket. You can get the cameras HERE.

Arduino, Tutorial

ARDUINO TUTORIAL 67: Create a Remote Controlled RGB LED with Brightness and Color Control

June 23, 2020 admin

In this video we give you a homework assignment to create a dimmable RGB LED. You must set color and brightness using the IR remote. In Tutorial 68 we will take you through the build, and show you the solution. I hope you will really try your best to do it on your own before you check out my solution.

Jetson Nano

AI on the Jetson Nano Lesson 46: Synchronizing Multiple Cameras with OpenCV

June 20, 2020 admin

In this lesson we learn how to use Python Classes, Methods and Threading to run two cameras in OpenCV without latency or synchronization problems. Below we include the code developed in the video above.

from threading import Thread
import cv2
import time
import numpy as np

class vStream:
    def __init__(self,src,width,height):
        self.width=width
        self.height=height
        self.capture=cv2.VideoCapture(src)
        self.thread=Thread(target=self.update,args=())
        self.thread.daemon=True
        self.thread.start()
    def update(self):
        while True:
            _,self.frame=self.capture.read()
            self.frame2=cv2.resize(self.frame,(self.width,self.height))
    def getFrame(self):
        return self.frame2
flip=2
dispW=640
dispH=480
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'
cam1=vStream(1,dispW,dispH)
cam2=vStream(camSet,dispW,dispH)
font=cv2.FONT_HERSHEY_SIMPLEX
startTime=time.time()
dtav=0
while True:
    try:
        myFrame1=cam1.getFrame()
        myFrame2=cam2.getFrame()
        myFrame3=np.hstack((myFrame1,myFrame2))
        dt=time.time()-startTime
        startTime=time.time()
        dtav=.9*dtav+.1*dt
        fps=1/dtav
        cv2.rectangle(myFrame3,(0,0),(140,40),(0,0,255),-1)
        cv2.putText(myFrame3,str(round(fps,1))+' fps',(0,25),font,.75,(0,255,255),2)
        cv2.imshow('ComboCam',myFrame3)
        cv2.moveWindow('ComboCam',0,0)



    except:
        print('frame not available')
        
    if cv2.waitKey(1)==ord('q'):
        cam1.capture.release()
        cam2.capture.release()
        cv2.destroyAllWindows()
        exit(1)
        break

from threading import Thread

import cv2

import time

import numpy as np

class vStream:

def __init__(self,src,width,height):

self.width=width

self.height=height

self.capture=cv2.VideoCapture(src)

self.thread=Thread(target=self.update,args=())

self.thread.daemon=True

self.thread.start()

def update(self):

while True:

_,self.frame=self.capture.read()

self.frame2=cv2.resize(self.frame,(self.width,self.height))

def getFrame(self):

return self.frame2

flip=2

dispW=640

dispH=480

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'

cam1=vStream(1,dispW,dispH)

cam2=vStream(camSet,dispW,dispH)

font=cv2.FONT_HERSHEY_SIMPLEX

startTime=time.time()

dtav=0

while True:

try:

myFrame1=cam1.getFrame()

myFrame2=cam2.getFrame()

myFrame3=np.hstack((myFrame1,myFrame2))

dt=time.time()-startTime

startTime=time.time()

dtav=.9*dtav+.1*dt

fps=1/dtav

cv2.rectangle(myFrame3,(0,0),(140,40),(0,0,255),-1)

cv2.putText(myFrame3,str(round(fps,1))+' fps',(0,25),font,.75,(0,255,255),2)

cv2.imshow('ComboCam',myFrame3)

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

except:

print('frame not available')

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

cam1.capture.release()

cam2.capture.release()

cv2.destroyAllWindows()

exit(1)

break

Technology Tutorials

Jetson Xavier NX Lesson 7: Connecting and Controlling Servos

ARDUINO TUTORIAL 68: Make a Remote Controlled RGB LED with Brightness and Color Control

Jetson Xavier NX Lesson 6: Camera Gear and Setup for Future Lessons

ARDUINO TUTORIAL 67: Create a Remote Controlled RGB LED with Brightness and Color Control

AI on the Jetson Nano Lesson 46: Synchronizing Multiple Cameras with OpenCV

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