Rotation* Sensor Block

This block counts the number of ticks (16 to a rotation) that your motor turns. Through data wires, this block can send out the current number of ticks and a logic signal (true/false) based on whether the number of ticks falls above or below a trigger point

* This sensor requires a converter cable to connect to the NXT. Please contact LEGO Education for more information. (http://www.lego.com/education/)

A trigger point is the specific value in a range of numbers where a change in condition occurs. For example, you might program your robot to stop when the number of ticks passes 160 (which is equal to 10 rotations). The trigger point would be 160.

Specify the trigger point by typing a value into the input box. To specify the range (above or below the trigger point) that will generate the “true” signal, use the pull-down menu to choose greater than or less than [the trigger point].

The default setting for the Rotation* Sensor block is for ticks above 16 (16 to a rotation) to generate a “true” signal. To switch the “true” portions of the range (setting values below 16 as “true”), you choose “less than” in the pull-down menu.

The feedback box in the configuration panel shows the current number of ticks (16 to a rotation). (To receive feedback, make sure that the sensor is connected to the chosen port and that communication has been established with the NXT.)

You must drag at least one output data wire from this block’s data hub to another block for any information to be sent. (See the Data Hub section below for more information.)

Display Settings

1. The number shows which of your NXT’s ports are connected to the Rotation Sensor. You can change this number in the configuration panel if you need to.
2. This icons shows which direction the sensor will be monitoring: forwards or backwards.
3. This icons shows whether the block is set to read ticks (16 to a rotation) or to reset the sensor.
4. The block’s data hub will open automatically when the block is placed in the work area. At least one data wire must be dragged from the block’s output plug to another block’s data hub.

Configuring the Rotation* Sensor Block

1. Choose the port where your rotation sensor is plugged in. By default, the block will be set to port 2 for a rotation sensor. You can change this selection if you need to.
2. Set the direction you want to monitor using the radio buttons: forwards or backwards.
3. Type the trigger value into the input box and use the pull-down menu to specify whether you want the “true” region to be greater than the trigger value or less than it.
4. The feedback box displays the current number of ticks (16 to a rotation). The Reset button will return the value to zero.

Configuring the Rotation* Sensor block’s Data Hub

You can control the Rotation* Sensor block dynamically by connecting data wires (from other blocks’ data hubs) to the Rotation* Sensor block’s data hub.

Open a block’s data hub by clicking the tab at the lower left edge of the block after it has been placed on the work area.

Data wires carrying input information to a block are connected to the plugs on the left side of its data hub. Data wires carrying output information are connected to the plugs on the right side.

[A] Input plug
[B] Output plug
[C] Number data wire (yellow)
[D] Logic data wire (green)
[E] Text data wire (orange)
[F] Broken data wire (gray)

Passing data from the input plug to the output plug

If an input plug has a corresponding output plug (see A above), the input data will pass through from the input plug to the output plug without being changed. In this case, you can only use the output plug if the input plug is connected to an input data wire; connecting an output data wire to such an output plug without a connected input data wire will cause the output data wire to be “broken” (and colored gray).

Data wires carry specific types of data

Each data wire carries a specific type of data between blocks. For example, if a data wire is dragged from a logic plug on a block’s data hub, it can only be connected to a logic plug on another block’s data hub. The chart below shows what kind of data each plug can accept or send out.

Data wire colors

Data wires are identified with specific colors: wires carrying number data are colored yellow, wires carrying logic data are colored green, and wires carrying text data are colored orange.

“Broken” data wires

If you try to connect a data wire to a plug of the wrong data type, the data wire will be broken (and colored gray). You will not be able to download your program if a data wire is broken.

If you click a broken wire you can read why it is broken in the small help window in the lower right corner of the work area.

Data must be within the possible range of the plug

If an input data wire transmits a value outside the possible range of the plug it is connected to, the block will either ignore the value or change it to a value within its range. For plugs that allow just a few input values (example: just 0, 1, or 2), the plug will ignore the input if a value arrives outside its range.

For plugs that accept larger input ranges (example: 0 – 100), the plug will force any input outside its range to fit. For example, if a Move block’s Power plug receives an input value of 150, the block will change the input value to 100 (i.e., a number within the Power plug’s range).

This chart shows the different characteristics of the plugs on the Rotation* Sensor block’s data hub:

	Plug	Data Type	Possible Range	What the Values Mean	This Plug is Ignored When...
	Port	Number	1 - 4	1 = Port 1, 2 = Port 2, 3 = Port 3, 4 = Port 4
	Trigger Point	Number	0 - 2147483647	Value to compare against
	Trigger Point Direction	Logic	True/False	Direction to use in comparison: True = Forwards, False = Backwards
	Greater / Less	Logic	True/False	Logic used in comparison: True = Greater, False = Less
	Reset	Logic	True/False	True = Reset, False = Read
	Yes / No	Logic	True/False	Result of comparison
	Direction	Logic	True/False	True = Forwards, False = Backwards
	Ticks	Number	0 - 2147483647	Scaled value read from sensor.