Arduino Tutorial 5 - Reading a Remote Control

Transcription

1 Arduino Tutorial 5 - Reading a Remote Control Recap : In week 2 we used Blink a LED ; In week 3 we read a sensor input (buttons on LCD); Last week (week4) we used Conditional Statements If; Else; Switch/Case. This week we combine all three: read infra red sensor, then blink coloured LEDs using IF. Plus how to read specification sheets for a 10mm LED and the IR sensor (AX-1838). Background : Remote controls are commonly used to control household devices, such as TV; Air Conditioner; DVD ; Stereo players; etc. A transmitter (the hand control) sends a burst or string of ON/OFF pulses to a receiver (sensor). Each button on the remote control has a specific string of pulses. We are going to read the string, and then take action to blink a coloured LED - Blue LED when the UP button pressed,; Green for DOWN; and yellow for LEFT. Project : To combine 3 features into one sketch - 1. Start with - Blink LEDs, using 3 different coloured 10mm LEDs. 2. Then add - Read the output from an infra red sensor ( remote control); 3. Then add - Use the IF command to choose which LED to blink. 1. Blink LEDs Select a 10mm Blue LED and 91 ohm resistor; a Green LED + a 91 ohm resistor and a Yellow LED ohm resistor. Why different value resistors? (See spec sheet). Carefully plug your prototype shield on top of your Arduino. Then, using the breadboard - * Plug the ANODE of the Blue LED into pin 4; Plug the CATHODE into the breadboard. * Connect one leg of the 91 ohm resistor to the Cathode. * Connect the other end of the resistor to earth. (photo on page 3). Repeat this for the Green LED to pin 8; and the Yellow LED to pin 12. Open the IDE (this will begin a blank sketch). Start with the /* and add a header comment to explain this sketch; For example control blinking LEDs using an IR remote control Include your name and date; End your header comment with */ Create 3 new integer variables - int blue_led = 4; int green_led = 8; int yellow_led = 12; Add comments using // beside each variable In setup(), set the mode of each LED pin to OUTPUT, using the pinmode command. In setup(), set each LED pin to LOW (eg turned off), using the digitalwrite command. In loop(), enter the command light_leds(); // This is a new user created function. Click New Tab (small arrow in top right of IDE); name the new tab MY_leds; In this new tab, type - void light_leds() then type open and closed curly braces. Between the curly braces, add the code as in the example Blink, to turn each coloured LED ON and OFF, using the digitalwrite command and the delay command. Upload the sketch to your Arduino. Your 3 coloured LEDs should now be blinking on and off, in sequence - (use a delay of 100). SAVE this sketch as Arduino5. This ends part 1 Blink LEDs. In part 2 we read the sensor for the IR remote control, and print the values to the screen (monitor). In part 3 we control the ON/OFF of the LEDs, using the values from the remote. control

2 IR Types A remote control uses light in the infra red region. Most operate at 940 nm, which is invisible to humans; The receiver (sensor) has 3 pins Signal, Ground; +ve 5V;. Refer specification sheet for VS1838 (attached). Read the IR Plug your IR sensor into the breadboard. CARE make CERTAIN it is NOT plugged into joined cells. Connect a wire from Arduino +5v to the IR VCC (+ve) leg; Connect a wire from Arduino GND (-ve) to the IR GND leg. Connect a wire from the Arduino pin A3 to the IR SIGNAL pin On the IDE, click FILE - Sketchbook - IR_Remote_basic1 ( If this is not on your computer,, the code is printed on the last page of this tutorial.). A new window will open, with the IR_Remote_basic1 sketch loaded. Upload this sketch to your Arduno, then open your monitor window (icon in top right of IDE); Press the UP key on your remote, and note the 4 digit number printed on your screen. Repeat for the DOWN key and the LEFT key. You will use these numbers in your sketch. 2. ADD IR_remote to your Arduino5 sketch. We are now going to add the code from IR_Remote_basic1 to your Arduino5 sketch. You should have two (2) Arduino IDE windows open Arduino5 and IR_Remote_basic1. Change the size of the IDE windows, so they both fit side by side on your screen. On the IR_Remote_basic1, copy the code from #include... down to long my_ir=0; Paste this into your Arduino5 sketch, after your header comments. On the IR_Remote_basic1, copy the code inside setup(), and paste into your Arduino 5 setup(). SAVE your Arduino5. On your Arduino5 sketch, click New-tab (arrow top right of IDE), and name it Read_IR_sensor. On the IR_Remote_basic1, copy all the code from read_myir(). and paste into Arduino5 tab of Read_IR_sensor. On Arduino5, in the loop() section, add the command read_myir(); // a new user command SAVE Arduino5; You now have all the code for reading the IR remote control, added to your Arduino5 sketch. Lets check if it works correctly. First, on Arduino5 use // to comment out the command in void loop() for light_leds(); This ensures the only code being executed is read_myir(). Upload to your Arduino. Open the monitor window and test your remote control. 3. ADD code to blink the LEDs, based on which button of the remote control is pressed. Remove the // in loop() that commented out light_leds(). We need that section to work, now. At the start of Arduino5, (perhaps after long myir=0; ) add several new variables - int remote_up = xxxx; // insert the values read from your remote for up. int remote_down = yyyy; // insert values read from your remote for down int remote_left = zzzz; // insert values from your remote for left. On Arduino5, click the tab for MY_leds; Lets add the IF command to choose which LEDs to light, using the following code : if (myir == remote_up) // note the use of double = signs. // put the curly braces around your code that blinks the blue LED Add if (myir == remote_down) to blink green LED, and if (myir == remote_left) blink yellow LED. SAVE Arduino5; Upload, and TEST using your remote.!!!!! CONGRATULATIONS - you can now add remote control to ANY Arduino project.!!!!!

3 Exercise Add to your sketch, the code to turn all LEDs OFF, when the remote power button is pressed, and to resume blinking the LEDs, when the power button is pressed a second time. 1. Use your Arduino sketch to find the value when you press the power button on your remote 2. Create a new variable int remote_power = aaaa; // insert the value read from your remote. 3. Create a new variable boolean leds_on = true; 4. Create a New Tab called Led_OnOff (click the small arrow on top right of IDE) 5. In the new tab, create a new function - void led_on_off() if (myir == remote_power) // Check if the remote power button pressed. if (leds_on == true) // check if the LEDs are on,. leds_on = false; // if the LEDs are on, change leds-on to false. else // end if myir = remote power // end led_on_off() // if LEDs are NOT on and the power button pressed, turn them on. leds_on = true; myir = remote_up; // set myir to the blue LED. In the Loop section, after read_myir(); - add led_on_off(); // this checks if the user pressed the power button. - in front of light_leds(), add if(leds-on == true)... // we only want to light the LEDs, if the leds_on variable is true. TEST When you press the power button on your remote, the LEDs should stop blinking. Pressing the Up, Down or Left button should have no effect. When you press the power button a second time, the blue LED should blink. Pressing the Up, Down or Left button should now cause the different coloured LEDs to blink. Our Arduino tutorials are on our U3A Website - here.

4 Sketch for reading values from a remote control. /* This is an example for reading an Infra Red Remote control sensor. It displays a number on your computer monitor, for each button pressed on the remote control. You can then use these numbers in your projects, with an IF or Switch/Case statement. It uses a VS1838 receiver with the signal leg connected to pin A3 of the Arduino. Tested and working on the Arduino Uno and the Mega. Code modified from examples in the Public Domain. K. Adams Feb 2014 */ #include <IRremote.h> int RECV_PIN = A3; // Include the library that handles Infra Red signal processing. // This library is from Github - Shirriff. // NOTE!!!! ENSURE you use the Github Sherriff library. // A variable to store the pin your IR receiver is connected to. // You can connect to most Arduino pins (except pins 0 and 1). This example uses pin A3. IRrecv irrecv(recv_pin); decode_results results; // This is a function contained in the IRremote library, and stores // the value in "results". long myir = 0; // Variable to hold the code received from the IR remote sensor. void setup() Serial.begin(9600); irrecv.enableirin(); void loop() read_myir(); // Open a serial connection to your PC. Needed to print results on the monitor // Start the IR receiver // Call (execute) our user made function. void read_myir() // The code in this section, reads and prints the output from your remote control. if (irrecv.decode(&results)) // Read the remote code, and store it in the variable - results.value. myir = results.value; // store the value from the IR Remote, in our variable myir myir = abs(myir); // use the abs command, to ensure we only get +ve values, Serial.print("RAW code from Receiver - "); Serial.print(myIR); //Print the raw code to the serial monitor Serial.print(".. "); if (myir < ) // Ignor any large values. Samsung uses 4,100m as power button. if(myir > ) // Reduce any value > 100,000 to only 4 digits - easier to work with. myir = myir % 10000; // modulus takes the right most significant digits only. Serial.print("New code stored in variable myir = "); Serial.println(myIR); // print the new code eg just the left most 4 digits of the raw code. delay(10); // a delay to provide time before resume. irrecv.resume(); // Receive the next value from the IR receiver // end loop()

5 LED 10mm Yellow Datasheet - LL-1003UYC2D-Y2-3EC High intensity ; 10mm diameter package; Small viewing angle Blue LED Green LED: Diameter: 10mm Diameter: 10mm Viewing Angle: 25 Viewing Angle: 25 Emitting Color: Blue Emitting Color: Green Nanometer: 470nm Nanometer: 528nm MCD max.: 8000 mcd MCD max.: 12,000 mcd ma typ.: 20 ma ma typ.: 20 ma V typ.: 3,3 V V typ.: 3,3 V V max.: 3,6 V V max.: 3,6 V

6 DATASHEET - AX1838HS INFRARED RECEIVER MODULE Description TheAX-1838HS is miniaturized infrared receivers for remote control and other applications requiring improved ambient light rejection. The separate PIN diode and preamplifier IC are assembled on a single leadframe. The epoxy package contains a special IR filter. This module has excellent performance even in disturbed ambient light applications and provides protection against uncontrolled output pulses. Features Photo detector and preamplifier in one package. Internal filter for PCM frequency. Inner shield,good anti-interference ability. High immunity against ambient light. Improved shielding against electric field disturbance 3.0V or 5.0V supply voltage; low power consumption. TTL and CMOS compatibility. 8ms data pause time codes are acceptable. Applications: Optical switch Light detecting protion of remote contol AV instruments such as Audio,TV,VCR,CD,MD,DVD,etc. Home appliances such as Air-conditioner,Fan,etc. CATV set top boxes Multi-media Equipment Supply Voltage V Supply Current 1.5 ma Reception Distance 8 mtrs Peak Wavelength 940 nm