What is the main idea of the passage?

An infrared remote communicates by sending timed invisible-light codes that a device senses and matches to commands. (The passage follows the coded signal from remote diode through sensor, software, and action.)

Why does pointing the remote toward the device help?

Infrared light usually needs a reasonably clear path to the sensor. (The passage notes that walls block the path and that the device’s sensor must receive the flashes.)

What does “interfere” mean?

disturb the intended signal or make it harder to read (Other infrared sources can add signals that complicate detection of the remote’s pattern.)

What part produces the infrared flashes?

a light-emitting diode (The first paragraph places a light-emitting diode behind the remote’s dark window.)

The Remote That Talks in Invisible Light: Level 2 Reading Comprehension Questions

A television remote sends messages with infrared light. Human eyes cannot see this light, but a sensor on the television can detect it. A small light-emitting diode sits behind the remote's dark window.

Pressing a button does not send one steady beam. A chip switches the infrared light on and off in a timed pattern. The pattern includes a code for an action such as raising the volume. Different buttons produce different codes.

The television's sensor turns the flashes into an electrical signal. Its software checks the pattern and performs the matching command. Other infrared sources can sometimes interfere, and a wall usually blocks the direct path. That is why pointing the remote toward the device often helps.

Some phone cameras can make the remote's flashes appear as pale light because their sensors respond to wavelengths eyes miss. The camera does not make infrared visible in the room. It converts the sensor's response into an image on the screen.

Comprehension questions