Introduction: Easy DIY Home Automation (using Servo Switches)

By www.oomlout.co.uk/?blog
This Instructable is all about one of life's simple actions, flipping a light switch on and off.

At oomlout we do it many times a day, so many in fact it came to a point where we asked ourselves "Can't we get an Arduino to do this?". Of course we can, what follows is how we went about doing it.

With the help of some acrylic, nuts and bolts and a small hobby servo we have made a great little switcher (we're calling it our Servo Switcher - (SESW)).

Features:
  • No need to mess with any high voltage wiring.
  • Switch is still operable by hand.
  • Easy to make and assemble

Applications:
  • Simple light switching.
  • Can be paired with sensor to make for more complicated applications. (security lights, temperature control on ceiling fans, night lights, the possibilities are endless) (some sensing examples are in a video on step 3 ).
  • Wire up a switch to a socket and control anything that has a plug.

(shameless plug)
If you feel like skipping the building and getting straight to experimenting lovely kits are available from the oomlout.com shop

(a small video of it running a demo program (ie. light switch rave)

Step 1: Parts & Tools

Two options here.

Option 1: Purchase a lovely kit from oomlout.com
  • kits with all the acrylic, bolts and servo motor are available from oomlout.com's web shop (here)($20 or 3 for $40)

Option 2: Make your own.

Electronics
  • Mini Servo Motor - A small servo motor, these are available in many different power levels, but you will be requiring one of the stronger ones. We use (this one)(shipped from hong kong so can get quite pricey)

Nuts and Bolts: (available at home depot)
  • 3mm x 10mm bolt (x3)
  • 3mm nut (x2)
  • 3mm locknut (x1)
  • 3mm washer (x3)
  • 5mm washer (x4)
  • 6-32 x 1.25" machine screws (x2)

Acrylic - (several options)
  • Cut Your Own (Scroll Saw) -- Download the scroll saw pattern (03-(SESW)-Scrollsaw Pattern.pdf) glue it to a piece of 3mm Acrylic, cut and drill
  • Cut Your Own (Laser Cutter) -- Download (00-SESW-Parts File.eps or .cdr) and cut it on your laser cutter using 3mm acrylic

Attachments

Step 2: Assembly & Wiring

With all the pieces ready to go what comes next is throwing them together.

Download the ".pdf" assembly guide below and follow the steps. (04-(SESW)-Assembly Guide.pdf)

A Few Notes:
  • A small 3mm hole must be drilled in the servo horn before step 3
  • In Step 4 when attaching the servo horn first rotate the servo as far clockwise (looking at the top) as it will let you go. Then attach the servo horn in it's full upright position.

Wiring:
  • Wiring is super simple. The servo plug has three pins which should be connected as follows
    • Pin 1  -  black or brown  -  gnd      Pin 2  -  red             -  power   Pin 3  -  white or orange -  signal
Pin 1 - attach to the negative side of your power supply (-)
Pin 2 - attach to positive power (4.8v - 6v)
Pin 3 - attach to pin 9 or 10 of your Arduino (or provide with a pulse between 1000 and 2000 mS for more details on controlling servos try (here)

Attachments

Step 3: Programming

With your Servo Switch all assembled and attached to the wall all that's left is programming. Let's get that test program loaded (if you ordered an arduino with your kit this program will come pre loaded)

What it does
  • The program will start up, turn your light switch on. Then wait five seconds before turning it off again. You will be having your very own light switch rave.
  • There are also a couple of demo modes in the program as demonstrated in this video.


For details on how to wire up for each demo mode please refer to the code. Here is a summary of the parts used.
  • Demo Mode 1 - Button - Simple Micro Switch found (here)
  • Demo Mode 2 - Proximity Sensor - IR proximity sensor found (here)
  • Demo Mode 3 - Photo Resistor found (here)

How to download the code to your Arduino

Option 1 - Downloading and unzipping
  • Download the attached zip file (05_SESW_Test.zip)
  • Unzip it to your Arduino sketch directory (default /My Documents/Arduino/)
  • Start the Arduino environment and load the sketch (_SESW_Test)
  • upload and start playing

Option 2 - Copy and Pasting
  • Copy the Arduino code from below
  • Paste it into the Arduino development environment.
  • upload and start playing

How to Use Servo Switches in your own Code
  • copy and paste the sections from the test program between (// Servo Switch - (SESW) Preamble START) and (// Servo Switch - (SESW) Preamble END) to the top of your sketch
  • copy and paste the sections from the test program between (// Servo Switch - (SESW) Routines START) and (// Servo Switch - (SESW) Routines END) to the bottom of your sketch
  • call servoSwitchSetup(); in your setup() routine
  • then to use turnOn() and turnOff()
  • adjustments can be made to support more servo switches.

Appendix 1 - Arduino Code (_SESW_Test)
//START OF NUNCHUCK PREAMBLE - For more in depth information please visit the original source of this code http://www.windmeadow.com/node/42 
//-------------------------------------------------
/*
 * Wiring Details
 * white  - ground
 * red    - 3.3+v  - 5 volts seems to work
 * green  - data   - Analog 4
 * yellow - clock  - Analog 5
 */

#include  #include   #undef int #include   uint8_t outbuf[6];		// array to store arduino output int cnt = 0;                    // counter used for nunchuck comunication int ledPin = 13;  int nunchuckValues[] = {0,0,0,0,0,0,0,0,0,0}; //An array to store the nuncheck values  /*  * The index of each value within the nunchuckValues[] array  * ie. XSTICK value is stored at nunchuckValues[XSTICK] (0)  */ #define XSTICK 0      //The joystick values      #define YSTICK 1 #define XAXIS 2       //The three accelerometer values      #define YAXIS 3         #define ZAXIS 4  #define ZBUTTON 5     //Front button values  (0 when pressed)   #define CBUTTON 6   #define XAXISDELTA 7  //Change in accelerometer data from last read; #define YAXISDELTA 8    #define ZAXISDELTA 9   //Nunchuck G calculating Constants /*  * For scaling the raw values from the nunchuck into G values  * Details on callibration and the maths can be found at  *    http://www.wiili.org/index.php/Motion_analysis  (Copied from http://www.wiili.org/index.php/Motion_analysis)      Zero Points        x_0 = (x_1 + x_2) / 2\,y_0 = (y_1 + y_3) / 2\,z_0 = (z_2 + z_3) / 2\,      One G points        x = \frac{x_{raw} - x_0}{x_3 - x_0}y = \frac{y_{raw} - y_0}{y_2 - y_0}z = \frac{z_{raw} - z_0}{z_1 - z_0} */  /* Not all of these are used and could be deleted (kept to make interpretting math's  * Easier 0-Zero G Value 1-Value when laying on table 2-Value when resting on nose  * 3-Value when resting on side (left side up) */ #define X0 500  #define X1 500 #define X2 500 #define X3 711  #define Y0 465 #define Y1 481 #define Y2 621 #define Y3 449  #define Z0 578 #define Z1 785 #define Z2 575 #define Z3 582  //END OF NUNCHUCK PREAMBLE - For more in depth information please visit the original source of this code http://www.windmeadow.com/node/42  //------------------------------------------------------  //-------------------------------------------------------------------------- // START OF ARDUINO CONTROLLED SERVO ROBOT (SERB) PREAMBLE #include   #define LEFTSERVOPIN  10   #define RIGHTSERVOPIN  9  #define MAXSPEED 10  //due to the way continuous rotation servos work maximum speed is reached at a much lower value than 90 (this value will change depending on your servos) (for Parallax servos)  Servo leftServo;  Servo rightServo;   int leftSpeed = 100;  //sets the speed of the robot (left servos)                        //a percentage between -MAXSPEED and MAXSPEED int rightSpeed = 100;  //sets the speed of the robot (both servos)                        //a percentage between -MAXSPEED and MAXSPEED int speed = 100;      //used for simple control (goForward, goBackward, goLeft, and goRight                       //a percentage between 0 and MAXSPEED   // END OF ARDUINO CONTROLLED SERVO ROBOT (SERB) PREAMBLE //--------------------------------------------------------------------------  long lastPrint; //a long variable to store the time the wiimote state was last printed #define PRINTINTERVAL 1000  //the number of milliseconds between outputting the nunchuck state over the usb port #define DEADBAND 20         //A percentage away from center that is interpretted as still being zero   void setup(){   Serial.begin(9600);   //Starts the serial port (used for debuging however makes servos jumpy)   nunchuck_init ();     // send the nunchuck initilization handshake   serbSetup();         // adds the servos and prepares all SERB related variables   lastPrint = millis(); }   void loop(){   readNunchuck();       //Reads the current state of the nunchucks buttons and accelerometers   if(!getNunValue(ZBUTTON)){     moveWiiAcelerometer();            //moves the wii deoending on the nunchucks acceleration values    }else{     moveWiiJoystick();   }   if((millis() - lastPrint) > PRINTINTERVAL){  //If a second has passed since last printing nunchuck values print them     printData();          //print nunchuck values     Serial.println();     //add an enter     lastPrint = millis(); //store current time as lastPrint   }  }  void moveWiiAcelerometer(){  moveDifferential(getYGs() * (float)100,getXGs()*(float)100);  }  void moveWiiJoystick(){  moveDifferential(map(getNunValue(YSTICK),30,220,-100,100),map(getNunValue(XSTICK),30,220,-100,100));  }  //Takes in a speed and a direction input (like a joystick) and translates it to speed commands  void moveDifferential(int speed1, int direction1){   speed1 = deadBandFilter(speed1);   direction1 = deadBandFilter(direction1);   setSpeedLeft(speed1 + direction1);   setSpeedRight(speed1 - direction1); }  int deadBandFilter(int value){  if(value > -DEADBAND && value < DEADBAND){value = 0;}  else{    if(value > 0){value = value - DEADBAND * 100 / (100-DEADBAND);}    else{value = value + DEADBAND * 100 / (100-DEADBAND);}  }  return value;  }   //START OF NUNCHUCK ROUTINES //-------------------------------------------------------------------------------------------------------   //Calculates and returns the xAxis acceleration in Gs float getXGs(){   return ((float)getNunValue(XAXIS) - X0) / (X3 - X0); }  //Calculates and returns the yAxis acceleration in Gs float getYGs(){   return ((float)getNunValue(YAXIS) - Y0) / (Y2 - Y0); }  //Calculates and returns the zAxis acceleration in Gs float getZGs(){   return ((float)getNunValue(YAXIS) - Z0) / (Z1 - Z0);   }  //START OF NUNCHUCK Reading CODE - For more in depth information please visit the original source  //of this code http://www.windmeadow.com/node/42  //--------------------------------------------------------------- void readNunchuck(){   Wire.requestFrom (0x52, 6);	// request data from nunchuck   while (Wire.available ()) {       outbuf[cnt] = nunchuk_decode_byte (Wire.receive ());	// receive byte as an integer       digitalWrite (ledPin, HIGH);	// sets the LED on       cnt++;     }    // If we recieved the 6 bytes, then go print them   if (cnt >= 5) {         nunchuckValues[XSTICK] = outbuf[0];         nunchuckValues[YSTICK] = outbuf[1];         int tempNun_xAxis = outbuf[2] * 2 * 2;          int tempNun_yAxis = outbuf[3] * 2 * 2;           int tempNun_zAxis = outbuf[4] * 2 * 2;         nunchuckValues[ZBUTTON] = 0;         nunchuckValues[CBUTTON] = 0;           // byte outbuf[5] contains bits for z and c buttons          // it also contains the least significant bits for the accelerometer data          // so we have to check each bit of byte outbuf[5]         if ((outbuf[5] >> 0) & 1) { nunchuckValues[ZBUTTON] = 1; } //checking if Z button is pressed (0=pressed 1=unpressed)         if ((outbuf[5] >> 1) & 1) { nunchuckValues[CBUTTON] = 1; } //checking if C button is pressed (0=pressed 1=unpressed)         if ((outbuf[5] >> 2) & 1) { tempNun_xAxis += 2; } //adding second least significant bit to x_axis         if ((outbuf[5] >> 3) & 1) { tempNun_xAxis += 1; } //adding least significant bit to x_axis         if ((outbuf[5] >> 4) & 1) { tempNun_yAxis += 2; } //adding second least significant bit to y_axis         if ((outbuf[5] >> 5) & 1) { tempNun_yAxis += 1; } //adding least significant bit to x_axis         if ((outbuf[5] >> 6) & 1) { tempNun_zAxis += 2; } //adding second least significant bit to z_axis         if ((outbuf[5] >> 7) & 1) { tempNun_zAxis += 1; } ////adding least significant bit to x_axis          nunchuckValues[XAXISDELTA] = tempNun_xAxis - nunchuckValues[XAXIS];         nunchuckValues[XAXIS] = tempNun_xAxis;         nunchuckValues[YAXISDELTA] = tempNun_yAxis - nunchuckValues[YAXIS];         nunchuckValues[YAXIS] = tempNun_yAxis;         nunchuckValues[ZAXISDELTA] = tempNun_zAxis - nunchuckValues[ZAXIS];         nunchuckValues[ZAXIS] = tempNun_zAxis;     }   cnt = 0;   send_zero (); // send the request for next bytes }  int getNunValue(int valueIndex){   return nunchuckValues[valueIndex]; }  void nunchuck_init (){   Wire.begin ();		// join i2c bus with address 0x52   Wire.beginTransmission (0x52);	// transmit to device 0x52   Wire.send (0x40);		// sends memory address   Wire.send (0x00);		// sends sent a zero.     Wire.endTransmission ();	// stop transmitting }  void send_zero () {   Wire.beginTransmission (0x52);	// transmit to device 0x52   Wire.send (0x00);		// sends one byte   Wire.endTransmission ();	// stop transmitting }  // Encode data to format that most wiimote drivers except // only needed if you use one of the regular wiimote drivers char nunchuk_decode_byte (char x)  {   x = (x ^ 0x17) + 0x17;   return x; }  //END OF NUNCHUCK CODE - For more in depth information please visit the  //original source of this code http://www.windmeadow.com/node/42  //---------------------------------------------------------------  //------------------------------------------------------------------------ //START OF ARDUINO CONTROLLED SERVO ROBOT (SERB) ROUTINES  /*  * sets up your arduino to address your SERB using the included routines */ void serbSetup(){   setSpeed(speed);   pinMode(LEFTSERVOPIN, OUTPUT);     //sets the left servo signal pin                                       //to output   pinMode(RIGHTSERVOPIN, OUTPUT);    //sets the right servo signal pin                                       //to output   leftServo.attach(LEFTSERVOPIN);    //attaches left servo   rightServo.attach(RIGHTSERVOPIN);  //attaches right servo   goStop(); }   /*  * sets the speed of the robot between 0-(stopped) and 100-(full speed)  * NOTE: speed will not change the current speed you must change speed   * then call one of the go methods before changes occur. */  void setSpeed(int newSpeed){   if(newSpeed >= 100) {newSpeed = 100;}     //if speed is greater than 100                                              //make it 100   if(newSpeed <= 0) {newSpeed = 0;}         //if speed is less than 0 make                                              //it 0    speed = newSpeed * MAXSPEED / 100;        //scales the speed to be                                              //between 0 and MAXSPEED }  /*  * sets the speed of the robots rightServo between -100-(reversed) and 100-(forward)  * NOTE: calls to this routine will take effect imediatly */  void setSpeedRight(int newSpeed){   if(newSpeed >= 100) {newSpeed = 100;}     //if speed is greater than 100                                              //make it 100   if(newSpeed <= -100) {newSpeed = -100;}   //if speed is less than -100 make                                              //it -100    rightSpeed = newSpeed * MAXSPEED / 100;   //scales the speed to be                                              //between -MAXSPEED and MAXSPEED   rightServo.write(90 - rightSpeed);             //sends the new value to the servo }  /*  * sets the speed of the robots leftServo between -100-(reversed) and 100-(forward)  * NOTE: calls to this routine will take effect imediatly */  void setSpeedLeft(int newSpeed){   if(newSpeed >= 100) {newSpeed = 100;}     //if speed is greater than 100                                              //make it 100   if(newSpeed <= -100) {newSpeed = -100;}   //if speed is less than -100 make                                              //it -100    leftSpeed = newSpeed * MAXSPEED / 100;   //scales the speed to be                                              //between -MAXSPEED and MAXSPEED   leftServo.write(90 + leftSpeed);               //sends the new value to the servo }  /*  * sends the robot forwards  */ void goForward(){  leftServo.write(90 + speed);  rightServo.write(90 - speed); }  /*  * sends the robot backwards  */ void goBackward(){  leftServo.write(90 - speed);  rightServo.write(90 + speed); }    /*  * sends the robot right  */ void goRight(){  leftServo.write(90 + speed);  rightServo.write(90 + speed); }  /*  * sends the robot left  */ void goLeft(){  leftServo.write(90 - speed);  rightServo.write(90 - speed); }  /*  * stops the robot  */ void goStop(){  leftServo.write(90);  rightServo.write(90); }  //END OF ARDUINO CONTROLLED SERVO ROBOT (SERB) ROUTINES //---------------------------------------------------------------------------   //START  OF PRINT ROUTINES (can delete if not using) //---------------------------------------------------------------  //Prints the Nunchucks last read data (must call NUN_readNunchuck(); before calling void printData(){   Serial.print("XJoy= ");Serial.print (getNunValue(XSTICK), DEC); Serial.print ("\t");   Serial.print("YJoy= ");Serial.print (getNunValue(YSTICK), DEC); Serial.print ("\t");   Serial.print("XGs= ");Serial.print (getXGs() * 1000, DEC);  Serial.print ("\t");   Serial.print("YGs= ");Serial.print (getYGs() * 1000, DEC);  Serial.print ("\t");   Serial.print("ZGs= ");Serial.print (getZGs() * 1000, DEC);  Serial.print ("\t");   Serial.print("ZBut= ");Serial.print (getNunValue(ZBUTTON), DEC);  Serial.print ("\t");   Serial.print("YBut= ");Serial.print (getNunValue(CBUTTON), DEC);  Serial.print ("\t"); }  //END OF PRINT ROUTINES    //--------------------------------------------------------------------

Attachments

Step 4: Finished

Congrats, your switches are put together and causing the insanity that only an Arduino controlled light switch is capable of.

If you've encountered any difficulty or simply have a question to ask feel free to contact us in the comments or at help@oomlout.com.

Finally if you've built a Servo Switch or two or put a couple purchased ones to an interesting use send us a line (info@oomlout.com) we love to see what people are upto. We'll toss a photo and a link to your site up on this step.

Finally a tip of the hat as to what we're up to, we're going to put ours to use managing a fully internet connected lettuce farm (well several headed farm).