Big Question

How can devices be controlled using wireless technology?

Investigate

You will need the following components:

Arduino UNO Board
Breadboard
1 Infrared (IR) Receiver
1 Remote Control
3 Female-to-Male DuPont Wires
- 1 red, 1 black, 1 other color

Additionally, you will need the IRremote library installed in the Arduino IDE:

Download the ZIP file: IRremote-1.zip
Save it somewhere you'll remember (can be on your network drive)
Open the Arduino IDE
On the menu at the top, click Sketch
Mouse over Add Library
Click on Add .ZIP Library...
In the pop-up window, navigate to folder with the library file
Click the Open button

Infrared (IR) receivers and remotes have been used for many years to control lots of different devices. Most commonly, IR receivers are found on TVs so you can control them using a remote control. This allows you to change the channel, the volume or the settings without getting off the couch. IR technology is line-of-sight, meaning that there must not be any physical barrier between the receiver and the remote for the signal to be received because the remote must be pointed at the receiver to send data.

An IR remote has a circuit board with buttons and an IR LED. When a button is pressed, IR pulses are sent from the remote to the receiver that encoded with information about the button that was pressed. The receiver detects that IR signals are being transmitted, so it gets them and sends those along to a processor. The processor figures out what button was pressed and performs the action associated with the button press.

Procedure:

Connect the red DuPont wire from the R pin on the IR receiver to 5V on the Arduino
Connect the black DuPont wire from the G pin on the IR receiver to GND on the Arduino
Connect the other color DuPont wire from Y on the IR receiver to any PWM pin on the Arduino
Open the Arduino IDE and start a new sketch
Click Sketch, then mouse over Include Library and click on IRremote
Create an IR receiver in code using the pin you connected the receiver to
Create a variable to decode the results of the receiver
In the setup,
1. Enable the receiver for input
2. Start a Serial Monitor
In the main code,
1. Check if the receiver has gotten a signal
2. If so, print the results to the Serial Monitor
Plug the USB cable into the board and computer, upload the code, and start the Serial Monitor
Aim the remote at the receiver and press a key, check the Serial Monitor for results

Once the Serial Monitor is displaying numerical codes, save the sketch in your sketchbook as ir_receiver

Questions to answer:

How can the Arduino know what code belongs to which button?
What can technology like this be used for?

Share the answers to these questions before you move on

Try It Yourself

You will not be making any changes to your device. Save the open sketch in your sketchbook as ir_receiver_buttons.

You might notice that the codes being displayed on the Serial Monitor are inconsistent. In some cases, the same code appears no matter which button is pressed on the remote. This is a quirk of the device that we really can't solve. The actual codes for buttons are 8 digits long and unique to the button being pressed. Find codes for at least 4 of the buttons on the remote.

Using the Arduino IDE reference card:

For the main code,
1. When the IR receiver gets input, output the correct name of the button being pressed based on the code received
  Note: In this case, you are doing one of several different things based on the value of a variable
Plug the USB cable into the board and computer, upload the code, switch to the Serial Monitor, and test that each button will generate the correct name

Once the correct names are appearing for all your buttons, save the sketch.

Some common problems you may encounter:

Buttons aren't consistently resulting in names
- Receiver is mis-decoding the results (not your fault)
- Mistaken values are being used to determine what to print
Wrong button name is output
- Mistaken values are being used to determine what to print

Extensions

Try these extensions building on your learning from this lesson and previous units.

Extension 1: All Remote Buttons

Challenge: Output the name for every button on the remote based on the code that is received (should be simple to add if you used the appropriate structure for outputting the names)

Extension 2: Remote Control LEDs

Challenge: Use the remote control and IR receiver to turn LEDs on or off depending on which buttons are pressed

Extension 3: Remote Control Tones

Challenge: Use the remote control and IR receiver to output different tones on a passive buzzer

Advanced Extensions

Try these extensions after completing other lessons using libraries

Extension 4: Remote Control Character

Challenge: Move a character on the LCD screen using the buttons on the remote control

Extension 5: Remote Control Temperature

Challenge: Switch between outputting Celsius and Fahrenheit temperature from the temperature and humidity sensor using the remote control