Arduino uno User Manual

What If It Doesn’t Work?
If you cannot make this chapter’s code run, you should download the code
from the book’s website and try to run it. Make sure you’re using the correct
serial port in the code/RemoteControl/TvRemoteUI/js/remote.js file.
In this chapter, we mainly used LEDs and an Ethernet shield, so all of the
advice from Chapter 3, Building Binary Dice, on page 39, and Chapter 10,
Networking with Arduino, on page 163, also applies to this chapter.
In addition, you have to be careful of more things. The distance between an
infrared LED and its receiver is important. To be on the safe side, you should
position the LED near the receiver. It should also be placed right in front of
the receiver, and you should make sure there’s not too much ambient light
that might disturb the infrared signal.
For debugging purposes, it’s useful to replace an invisible infrared LED with
a regular LED from time to time. This way, you can see whether your circuit
works in principle.
If you’re trying to control a Mac, you should unpair any other remote controls
in the Security area of the Mac’s System Preferences window.
Finally, you might be using a device that uses a protocol that isn’t supported
by the IRremote library. In this case, you have to add it. This can be tricky,
but IRremote is open source, so at least it’s possible.
Exercises
• Build an emulator for a remote control you find in your household. Make
its commands available via serial port and via Ethernet.
• Instead of controlling the Arduino via a serial monitor or web browser,
control it using a Nintendo Nunchuk. You could move the analog stick
up and down to control your TV set’s volume, and you could move it left
or right to change the channel.
• Design a real universal remote control based on an Arduino. Look for a
touchscreen, a button pad, an SD card shield, and a Bluetooth module.
I bet you didn’t think you could build a device like this—but you know
everything you need to do it now.
report erratum • discuss
What If It Doesn’t Work? • 223
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Arduino uno Specifications

General

Form factor	Arduino
Certification	RoHS, FC, CE
Processor model	-
Processor frequency	- MHz
Microcontroller model	ATmega328
Microcontroller frequency	16 MHz
DC input voltage	7-12 V
Operating voltage	5 V
DC current per I/O pin	40 mA
Flash memory	0.032 MB
Maximum internal memory	- GB
SRAM (Static Random Access Memory)	2 KB
EEPROM (Electrically Erasable Programmable Read-Only Memory)	1 KB
Wi-Fi	No
Number of analog I/O pins	6
Number of digital I/O pins	14

Weight and Dimensions

Board dimensions	53.4 x 68.6 mm