This page is a random collection of notes addressed to myself. Nothing here is intended as a guide per say, however i have posted them hoping that it may help someone.
Blog about Arduino
http://arduino.cc/
Everything in this blog can be copied or edited GNU General Public License (version 2 or newer) http://www.gnu.org/licenses/gpl.html
Arduino course is now finished and I hope that I will write here again some day. Here are some projects our course did.
First on is push-up counter. It uses ultrasonic sensor to detect how close the doer is. Then it counts the amount of push-ups to the digital screen. It can be restarted with button. Simple, but works. No idea if someone needs this or not ?
Second one is some kind of watch tower or big brother tower. It turns 180 degrees and scans the area. If it detects movement, it stops and turns a led light on. The original idea was to make kitchen lights turn on and off automatically.
Third one was interesting. A robot hand. It is made of plastic bottle and cardboard. Every finger is connected to one servo motor with a thread and when it moves the hand "grabs". The hand-guy first tried to make a 3D print of hand but it failed because software incompatibilities.
Last one was a flashlight button tester. It can be set to push forever the flashlight button, it tests if the light turns on and if not it calculates it as error. It didn't save any log file yet but it was under work. Very useful tool for flashlight producers i'd say.
And my robot hat, teacher liked it. I got 4,5/5 points. That was very nice.
As my final project I got an idea about a hat which can talk to the user and guide example a blind guy to the right way and not to crash anything. Or one could solve a maze in complete darkness because the ultrasonic sensor. I first tried to make Arduino say something but it didn't succeed. Then I eased my project and thought maybe same kind of noise what car rear-view cameras make. I found Arduino Tone library. With that I managed to make Arduino Beep! Then I found a broken headset. I ripped the speaker elements out of it and soldered two wires to it. Then I connected the ultrasonic sensor which I got earlier hc-sr04 to Arduino, tested if it works and can measure the distance. I coded it to check if the distance is between three ranges. If the range is shorter than 30 centimeters it will beep very fast and warn the user that you are going to crash. If the distance is between 31 and 60 centimeters it will beep normal speed and it tells that it is safe to turn. If the distance is between 61 and 90 it beeps very slow to warn that you are approaching an obstacle. If the distance is bigger than 90 it stays silent. I think this was very fun project and of course interesting. Thanks to Tero Karvinen i'm now very excited about the Arduino and its possibilities. And then about the project.
I first started to code the project by one piece at a time. First the ultrasonic sensor, then the beep sound and then connected those together. Here i'm currently in test environment.
Next I had to hot glue all the parts to an old peaked cap and solder few wires together.
Then I tested if the parts still work without computer test environment and it didn't. I had to change the speaker connection a little bit and then it worked. Here is the final ultrasonic hat. The battery plus wire was too short but it is just long enough to work.
Testing phase for distance and beep to function correctly together.
And here it is. The final version of my prototype hat for the blind people or drunk people or what ever.
And how I coded it ? Here is the whole code.
Connection like in ultrasonic sensor post and tone post. hc-sr04 vcc to +5v, gnd to gnd, trig to pin 12, echo to pin 13. Speaker element goes to ground and digital pin 8.
//define the pins for ultrasonic sensor here
#define trigPin 12
#define echoPin 13
//setup trig is output and echo is input for the sound. Read serial fastest possible speed
void setup() {
Serial.begin (115200);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
//below methods for beep speed
void beepFast(){
// play a note on pin 8 for 200 ms:
tone(8, 440, 200);
delay(50);
// turn off tone function for pin 8:
noTone(8);
delay(300);
}
//no beep here
void beepNo(){
noTone(8);
delay(300);
}
//send a pulse and calculate how long it took to travel
void loop() {
int duration, distance;
digitalWrite(trigPin, HIGH);
delayMicroseconds(1000);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance = (duration/2) / 29.1;
//then check the distance and beep if it is in the range
if (distance >= 200 || distance <= 0){
Serial.println("Out of range");
}
else if (distance >=0 && distance <=30){
beepFast();
Serial.print(distance);
Serial.println(" cm");
}
else if (distance >=31 && distance <=60) {
Serial.print(distance);
Serial.println(" cm");
beepMedium();
}
else if (distance >=61 && distance <= 90){
Serial.print(distance);
Serial.println(" cm");
beepSlow();
}
else {
beepNo();
Serial.print(distance);
Serial.println(" cm");
}
}
And the guy behind this blog and random hat project...
Testing phase. She managed to walk to the door from kitchen and back. Succeed.
The project was fun to do and i'm proud that I managed to complete it. One thing more to add my portfolio.
Because I got the dc motor work with Arduino I thought maybe I should build a car. The idea was good but the actual car was bad. DO NOT build a car with weak dc motor. It runs very slow because the DC motors are so weak and the controlling of motors is also bad. Anyway here is a picture and a video to demonstrate it. I'm not even using Arduino because I just wanted to know if the motors are good for this kind of project. And the answer is definitely no.
As you can see it didn't even have enough power to run on carpet...
I discovered that Arduino can play simple beep sounds without anything special. I ripped the speaker element from old headphones, soldered two wires to it and connected to arduino GND and digital 8 through 100ohm resistor. It played continuous beep sound... was pretty fun.
Found the code from here: http://arduino.cc/en/Tutorial/Tone4
bEEp! bEEp! bEEp! bEEp! bEEp! bEEp!
void setup() {
}
void loop() {
// turn off tone function for pin 11:
noTone(11);
// play a note on pin 6 for 200 ms:
tone(8, 440, 200);
delay(200);
// turn off tone function for pin 6:
noTone(8);
delay(300);
To control small DC motor you will need:
motor, max 5v
PN2222 Transistor
1N4001 diode
270 Ω Resistor (red,
purple, brown stripes)
Connection scheme:
Add this code to arduino. You can control the speed of motor by sending values between 0 - 255 from serial monitor. However i noticed my DC motor doesnt work if the speed isn't between 150 - 255.
int motorPin = 3;
void setup()
{
pinMode(motorPin, OUTPUT);
Serial.begin(9600);
while (! Serial);
Serial.println("Speed 0 to 255");
}
void loop()
{
if (Serial.available())
{
int speed = Serial.parseInt();
if (speed >= 0 && speed <= 255)
{
analogWrite(motorPin, speed);
}
}
}
Project found from: http://learn.adafruit.com/adafruit-arduino-lesson-13-dc-motors/overview
I started to do the second project from Arduino book because I have limited parts to use and it seemed really interesting. So I started by gluing two servos together and disassembling two rc helicopters.
This is the first version of the Arduino insect:
The legs were really bad and it didn't move an inch. Then i followed the book and got two wire hangers. The legs were far more better and the insect even moved very slow. This is the second version or third version because I added the PING sensor to be the eyes. It doesn't work yet but i'm working on it.
Version 1 video:
And the actual code how it moves. The idea is to move servos at different time.
-------------------------------------------------------------------------
The insect can move by calling the method
-------------------------------------------------------------------------
#include <Servo.h>
Servo frontServo;
Servo rearServo;
int centerPos = 90;
int frontRightUp = 72;
int frontLeftUp = 108;
int backRightForward = 75;
int backLeftForward = 105;
-------------------------------------------------------------------------
Move turn left
-------------------------------------------------------------------------
#include <Servo.h>
Servo frontServo;
Servo rearServo;
int centerTurnPos = 81;
int frontTurnRightUp = 63;
int frontTurnLeftUp = 117;
int backTurnRightForward = 66;
int backTurnLeftForward = 96;
/*Servo motors global variables */
int centerPos = 90;
int frontRightUp = 72;
int frontLeftUp = 108;
int backRightForward = 75;
int backLeftForward = 105;
int walkSpeed = 150;
int centerTurnPos = 81;
int frontTurnRightUp = 63;
int frontTurnLeftUp = 117;
int backTurnRightForward = 66;
int backTurnLeftForward = 96;
This is the current version of insect with better legs. Now it can move forward a little bit better. It also has a place for PING sensor but I didn't add it yet.
