Tag: api

I took the leap and bought an Arduino from LiquidWare. Arduino is an open-source microcontroller that has a processor, some digital I/O pins, and analog inputs. You can create little standalone programs that monitor inputs, control LEDs, and pretty much anything that you dream up. My favorite projects are ones that involve the Internet. A microcontroller is rather simple by itself, but what if it could use the web to get answers, send an email, maybe update my Twitter status? That means there is an unlimited number of projects ahead – Microcontrollers collaborating in cyberspace. The missing link for the web part is the ioBridge IO-204. I know you are no stranger to the IO-204, but for those of you who have not heard. The IO-204 sits on my network and relays data from its channels to ioBridge.com servers and back into my network. It allows for remote control and monitoring without network configuration and programming. One of the expansion boards is a two-way serial board that accepts serial strings and connects them to APIs of web services that ioBridge interfaces to and sends back responses. For instance, I can send the commands, “[[[calc|9*9]]]” and this returns 81. OK, maybe not impressive on the surface, but that result came from Google Calculator. Anything Google Calculator can solve, your microcontroller has access to those results. For more examples, visit the Serial Web Services API on the wiki.

Source Code

The Arduino requires some c-like programming and I wanted to include the sketch for you to steal and use for your projects. You will see how I send the serial commands from the Arduino to the IO-204 using the UART serial connection (pins 0/1) and receive and parse the incoming results. I use a SoftwareSerial port for the LCD results. The pushbuttons are software debounced and use pull-up resistors for solid digital connections. The LED’s linked to each button use a 330-ohm resistor to protect them. I was aided by the Arduino Inputs tutorial on Ladyada.net, Debounce Tutorial, and the ioBridge Wiki / Forum. Please let me know if you have any questions, maybe I can help. I have learned a lot about handling strings on the Arduino.

//
// Message Center using Arduino and the ioBridge IO-204
//
// An open-souce Shadowlord Project
// www.IamShadowlord.com

#include SoftwareSerial.h>

// SoftwareSerial Pins
#define rxPin 2
#define txPin 3

// Setup Software Serial
SoftwareSerial softSerial = SoftwareSerial(rxPin, txPin);

// Global Setup
int middleLED = 11;
int rightLED = 10;
int leftLED = 12;

int leftButton = 5;
int leftButtonCurrent = LOW;
int leftButtonReading;
int leftButtonPrevious = HIGH;
long leftButtonTime = 0;
long leftButtonDebounce = 200;

int middleButton = 4;
int middleButtonCurrent = LOW;
int middleButtonReading;
int middleButtonPrevious = HIGH;
long middleButtonTime = 0;
long middleButtonDebounce = 200;

int rightButton = 6;
int rightButtonCurrent = LOW;
int rightButtonReading;
int rightButtonPrevious = HIGH;
long rightButtonTime = 0;
long rightButtonDebounce = 200;

int tempPin = 5;
int tempAnalog = 0;
int tempF = 0;

char* currentRequest = "";

// Start up program
void setup() {

pinMode(rxPin, INPUT);
pinMode(txPin, OUTPUT);

pinMode(leftLED, OUTPUT);
pinMode(middleLED, OUTPUT);
pinMode(rightLED, OUTPUT);

pinMode(leftButton, INPUT);
pinMode(middleButton, INPUT);
pinMode(rightButton, INPUT);

softSerial.begin(9600);
delay(100);

Serial.begin(9600);
delay(100);

Serial.flush();
delay(100);

// Setup LCD
clearLCD();
setBacklightBrightness(9);
delay(1000);

// Test LEDs
digitalWrite(leftLED, HIGH);
digitalWrite(middleLED, HIGH);
digitalWrite(rightLED, HIGH);

delay(1500);

digitalWrite(leftLED, LOW);
digitalWrite(middleLED, LOW);
digitalWrite(rightLED, LOW);

}

// Start main program loop
void loop(){

// Get Analog Input and scale as temperature for ioBridge temperature sensor on arduino
tempAnalog = analogRead(tempPin);
tempF = tempAnalog / 6.875;

// Monitor left button status and debounce
leftButtonReading = digitalRead(leftButton);

if (leftButtonReading == HIGH && leftButtonPrevious == LOW && 
          millis() - leftButtonTime > leftButtonDebounce) {
if (leftButtonCurrent == HIGH) leftButtonCurrent = LOW;
else {digitalWrite(leftLED, HIGH);
clearLCD();
delay(100);
softSerial.print("Outside: ");
delay(100);
softSerial.print(tempF);
delay(100);
moveCursor("02", "01");
delay(100);
softSerial.print("Atlanta: ");
leftButtonCurrent = LOW;
//Request temperature in Atlanta via ioBridge
Serial.print("[[[weather|Atlanta]]]");
digitalWrite(leftLED, LOW);
}
leftButtonTime = millis();
}

leftButtonPrevious = leftButtonReading;

// Monitor middle button status and debounce
middleButtonReading = digitalRead(middleButton);

if (middleButtonReading == HIGH && middleButtonPrevious == LOW &&
millis() - middleButtonTime > middleButtonDebounce) {
if (middleButtonCurrent == HIGH) middleButtonCurrent = LOW;
else {currentRequest = "Google";
digitalWrite(middleLED, HIGH);
clearLCD();delay(100);
softSerial.print("GOOG: $");
delay(100);
middleButtonCurrent = LOW;
//Request Google Stock Price via ioBridge  
Serial.print("[[[stock|GOOG]]]"); 
digitalWrite(middleLED, LOW);
}
middleButtonTime = millis();
}

middleButtonPrevious = middleButtonReading;

// Monitor right button status and debounce
rightButtonReading = digitalRead(rightButton);

if (rightButtonReading == HIGH && rightButtonPrevious == LOW &&
millis() - rightButtonTime > rightButtonDebounce) {
if (rightButtonCurrent == HIGH) rightButtonCurrent = LOW;
else {
digitalWrite(rightLED, HIGH);
clearLCD();
delay(100);
softSerial.print("Alert: ");
delay(100);
rightButtonCurrent = LOW;
//Send email via ioBridge  
Serial.print("[[[email|hans@nothans.com|Alert|Mom, is pressing your buttons]]]");
digitalWrite(rightLED, LOW);
}
rightButtonTime = millis();
}

rightButtonPrevious = rightButtonReading;

// Display serial messages
if(Serial.available() > 0){

delay(100);

char charIn = 0;
byte i = 0;
char stringIn[32] = "";

while(Serial.available()) {
charIn = Serial.read();
stringIn[i] = charIn;
i += 1;
}

if (currentRequest == "Google") {

softSerial.print(stringIn);
int stockPrice = atoi(stringIn);
delay(100);
moveCursor("02", "01");
delay(100);
stockPrice = stockPrice - 405;
softSerial.print("Change: $"); 
delay(100);
softSerial.print(stockPrice);
currentRequest = "";

}
elsesoftSerial.print(stringIn);
}

// End program loop     
}

//
// ioBridge Serial LCD Functions and Parameters (for SoftwareSerial)
//

void displayMessage(char* message){
softSerial.print(message);
}

void clearLCD(){
softSerial.print(0xFE, BYTE);
softSerial.print("Z");
}

void setBacklightBrightness(int level){
// level
// 0=Off -> 9=Brightest

softSerial.print(0xFE, BYTE);
softSerial.print("B");
softSerial.print(level);
}

void setBacklightTime(int level, byte seconds){
// level
// 0=Off -> 9=Brightest

// seconds
// 01 = 1 seconds => 06 = 60 seconds

softSerial.print(0xFE, BYTE);
softSerial.print("T");
softSerial.print(level);
softSerial.print(seconds, BYTE);
}

void moveCursorHome(){
softSerial.print(0xFE, BYTE);
softSerial.print("H");
}

void turnCursorOn(){
softSerial.print(0xFE, BYTE);
softSerial.print("J");
}

void turnCursorOff(){
softSerial.print(0xFE, BYTE);
softSerial.print("K");
}

void turnBlinkingCursorOn(){
softSerial.print(0xFE, BYTE);
softSerial.print("P");
}

void turnBlinkingCursorOff(){
softSerial.print(0xFE, BYTE);
softSerial.print("Q");
}

void scrollMessage(int row, int speed, char* message){
// row
// 1=First Line -> 2=Second Line

// speed
// 0=Slowest -> 9=Fastest

softSerial.print(0xFE, BYTE);
softSerial.print("S");
softSerial.print(row);
softSerial.print(speed);
softSerial.print(message);
softSerial.print(0xFE, BYTE);
}

void moveCursor(char* row, char* column){
// row
// 01=First Line -> 02=Second Line

// column
// 01=First Position -> 16=Last Position

softSerial.print(0xFE, BYTE);
softSerial.print("L");
softSerial.print(row);
softSerial.print(column);
}

void drawHorizontalGauge(int row, char* leftLabel, char* rightLabel, char* length){
// row
// 1=First Line -> 2=Second Line

// leftLabel and rightLabel
// 2 character labels

// length
// a=Empty -> k=Full (filled in from left to right)

softSerial.print(0xFE, BYTE);
softSerial.print("G");
softSerial.print(row);
softSerial.print(leftLabel);
softSerial.print(rightLabel);
softSerial.print(length);
}

void drawVerticalGauge(int height){
// height
// 0=Bottom -> 8=Top (filled in from bottom to top)

softSerial.print(0xFE, BYTE);
softSerial.print("V");
softSerial.print(height);

}

Bonus Project

It’s simple, but I hacked together a power supply for the Arduino, which gets power from USB or a coaxial input from a transformer. I wanted to only run one brick, wall wart, so I hacked a USB cable. There are 4 wires in the USB cable (from pinouts.ru):

The IO-204 has a regulated 5VDC and ground (up to 1A – 4A total draw depending on supply) on each channel, so using a terminal strip, I connected the VCC and GND to a cut in half USB cable.

It’s magic – look ma, only one power source.