Infrared Sensor

Remote Infrared Beacon

In Beacon mode, the Infrared Sensor can detect the approximate position of the Remote Infrared Beacon (IR Beacon) in front of the sensor. The sensor can give you the beacon’s Proximity (relative distance from the sensor) and its Heading (angle from the direction the sensor is pointing). You could use the Beacon mode, for example, to make your robot seek out and drive toward the IR Beacon.

Turn on the Beacon and Choose a Channel

Turn the beacon on by pressing the Beacon Mode button on the top of the IR Beacon. The LED Indicator will turn on and stay on. The beacon will stay on and transmit continuously until you press the Beacon Mode button again to turn it off.

Choose one of the four channels from the Channel Selector. The Infrared Sensor will only detect a beacon on the channel that you specify in your program.

Infrared Sensor Beacon Mode Data

In Beacon mode, the Infrared Sensor gives the following data:

Data	Type	Values	Notes
Detected	Logic	True/False	True if an IR Beacon is detected on the specified channel, otherwise False.
Proximity	Numeric	0 to 100	The relative distance to the beacon. 0 means very close, and 100 means far away. The Proximity will be 100 if the beacon is not detected at all.
Heading	Numeric	-25 to 25	0 means the beacon is directly in front of the sensor, negative values are to the left, and positive values are to the right.

Tips and Tricks

The values for Proximity and Heading do not correspond directly to specific distances and angles. The values will depend on the strength of the signal and other factors.

Example

This program will make a robot start driving when the IR Beacon is on and gets close enough to the Infrared Sensor. It uses the Wait block in the Infrared Sensor – Compare – Beacon Proximity mode to wait for the Proximity to be less than 20, then it drives forward for 2 seconds.

Infrared Sensor Beacon Mode Blocks and Modes

The table below shows all of the programming blocks and modes that you can use with the Infrared Sensor in Beacon mode.

Block	Mode	Use
Wait	Infrared Sensor – Compare – Beacon Heading	Wait for the beacon to be detected and for the Heading to reach a specified value.
Wait	Infrared Sensor – Compare – Beacon Proximity	Wait for the beacon to be detected and for the Proximity to reach a specified value.
Wait	Infrared Sensor – Change - Beacon Heading	Wait for the beacon Heading to change by a specified amount.
Wait	Infrared Sensor – Change - Beacon Proximity	Wait for the beacon Proximity to change by a specified amount.
Loop	Infrared Sensor – Beacon Heading	Repeat a sequence of blocks until the beacon Heading reaches a specified value.
Loop	Infrared Sensor – Beacon Proximity	Repeat a sequence of blocks until the beacon Proximity reaches a specified value.
Switch	Infrared Sensor – Beacon Heading	Choose between two sequences of blocks depending on the beacon Heading.
Switch	Infrared Sensor – Beacon Proximity	Choose between two sequences of blocks depending on the beacon Proximity.
Infrared Sensor	Measure - Beacon	Get the beacon Heading and Proximity on Numeric data wires, and the Detected state on a Logic data wire.
Infrared Sensor	Compare – Beacon Heading	Compare the beacon Heading to a threshold, and get the result on a Logic data wire.
Infrared Sensor	Compare – Beacon Proximity	Compare the beacon Proximity to a threshold, and get the result on a Logic data wire.

Using the Infrared Sensor Beacon Mode