Gyro Sensor Block

This block measures the rate of rotation and the direction of rotation in the horizontal plane of the sensor. It returns the reading as the number of degrees per second of rotation. 

The block has the capability to adjust for the offset or bias of the sensor ensuring the output is zero when no rotation is present.

There is also a boolean output which returns "true" whenever the rate of rotation is greater or less than a defined trigger value.

You must drag at least one output data wire from this block's data hub to another block for any information to be sent.

Display Settings

1. The number shows which of your NXT's ports are connected to the Gyro Sensor. You can change this number in the configuration panel if you need to.
2. 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. (See the Data Hub section below for more information.)

Configuring the Gyro Sensor Block

1. Choose the Port where your Gyro Sensor is plugged in. By default, the block will be set to port 3 for a Gyro Sensor. You can change this selection if you need to.
2. The zero offset or bias can be adjusted for by placing the value obtained from the sensor when it is not rotating into the Offset field.
3. You can adjust the Compare value at which the trigger output will change.
4. The trigger output can either select greater than or less than by selecting the Trigger type.

Configuring the Gyro Sensor block's Data Hub

You can control the Gyro Sensor block dynamically by connecting data wires (from other block's data hubs) to the Gyro 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).

Gyro Sensor block Data Hub plugs

You must click on the Data Hub to open it as shown.

1. This plug wires the number for which of your NXT's ports are connected to the Gyro Sensor. 

2. This plug inputs the trigger value.
3. This plug inputs the trigger compare mode.
4. This plug outputs the trigger.
5. This plug inputs the offset value.
6. This plug outputs the measured rotation rate value.

The rotation rate output indicates the rotation rate measured in degrees per second up to a maximum of +/- 400 degrees per second. When the sensor is completely still, the output should be zero. Due to manufacturing tolerances, temperature and other effects such as aging, the output may be a small positive or negative number when stationary. To cancel out this zero offset error, also referred to as bias, an offset input can be applied.

Offsetting bias

The simplest way to measure and offset the bias, is to keep the sensor completely still and read the output with the Offset value set to zero. This value can then be used in the future as the Offset value which will then cause the output value to be zero when no rotation is present.