Timer

Timer Block

When your program starts, the three built-in timers in the NXT will automatically start counting. With this block you can choose to either read a timer’s current value or cause a timer to start counting again from zero.

Through data wires, this block can send out the current timer value and a logic signal (true/false) based on whether the timer value falls above or below a trigger point.

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 timer counts past 20 seconds. The trigger point would be 20 seconds.

Specify the trigger point by typing a number 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].

For the Timer block to function, you must drag a data wire from the block's data hub and attach it to another block's data hub. You can drag two kinds of output data wires from the Timer block's data hub: a logic data wire that will send out a true/false signal, and a number (#) data wire that will send out the timer's current value.

You can also supply the trigger value dynamically by connecting an input data wire to the Timer block's data hub. (See the Data Hub section below for more information.)

Display Settings

1.   This number shows which of the three timers in the NXT you will be monitoring. You can change to another timer in the configuration panel if you need to.

2.   The block's data hub will open automatically when the block is attached to the sequence beam, allowing you to drag out a logic (true/false) data wire or a number (#) data wire that will transmit the timer's current time value. You can also supply the trigger value dynamically by connecting an input data wire to the Timer block's data hub.

Note: you must drag at least one output data wire from the Timer block's data hub to another block for any information to be sent.

 

Configuring the Timer Block      

         

       

1.   Choose which of the three timers in the NXT you would like to view or control.

2.   If you choose the action property "Read," the Timer block will monitor an existing timer that has already been set up somewhere else in your

        program. If you choose "Reset," the block will reset the chosen timer and make it start over. You can position another Timer block later in your

        program to check on its progress.

3.   Type the trigger value (in seconds) into the input box and use the pull-down menu to specify whether you want the "true" region to be greater

         than or less than the trigger value.