Configurable ChapR Settings

The ChapR has a whole bunch of settings that change everything from the way it behaves with the robot to the length of time it will stay on before automatically turning off.  And you can change those settings!

The easiest way to change those settings is by using a Flash Drive.  Here’s the idea:

  1. Decide what setting you would like to change from the table below.
  2. Create a TEXT file on the flash drive with the new setting (do not put “.txt” into the filename, because Windows adds that automatically).
  3. Put the flash drive into Port 2 on the ChapR and let it read the new setting (or settings if you use multiple different files).
  4. Reboot the ChapR to ensure that the new settings are enabled.

Below is a list of the settings that can be changed.  Also, this table includes the name of the text file that you need to create on the flash drive. For more of a tutorial about using the flash drive, or if you are having problems, see this page.

See the bottom of the table for important notes about configuring the ChapR with a flash drive!

Filename Description/Content Example
name.txt Sets the Bluetooth name of the ChapR.
Your ChapR comes with a unique name; something like “ChapR-85”. This name is used to identify your ChapR when you are pairing with it from the NXT brick. Normally, you don’t need to change the name, but you can if you want. The name must be 15 characters or less and you must have no other characters or spaces in or after the name. Either have nothing or a simple RETURN/ENTER after the name in the text file.
timeout.txt Sets the number of minutes of inactivity before the ChapR turns off.
If you stop using the ChapR, it will automatically turn off to save battery. By default, this is set to 10 minutes. To change this, write the number of minutes you would like into the text file. This ranges from 0 (meaning no timeout ever) to 120. Only use numbers in the file and either have nothing or a simple RETURN/ENTER after the number in the text file.
person.txt Sets the “personality” of the ChapR for working with different robots.
Different robots have different behaviors and methods of communication. The ChapR needs to know what type of robot it is talking to so it can adjust its personality to match the robot. The personality is set by putting a single number in the text file:

1 FTC-style robot using the NXT brick running with RobotC
2 FLL-style robot using the NXT brick running with NXT-G
3 FTC-style robot using the NXT brick running with LabVIEW
4 FRC-style robot using the roboRIO

Either have nothing or a simple RETURN/ENTER after the number in the text file.

lag.txt Sets the control lag between the ChapR and robot.
Your ChapR is a fast little device. It is very good at driving your robot with very little “lag” – that is, the ChapR sends the controls from your joystick to the robot very quickly so you don’t experience a delay between the movement of the joystick and the robot. In fact, the ChapR is too fast for most NXT bricks! The lag setting is used to make sure that the ChapR isn’t running too fast for the NXT. By default, it is set to 35 for personalities 1-3 (FLL and FTC) and 0 for personality 4 (FRC). It refers to the number of milliseconds between the sending of commands from the ChapR to the robot. We recommend leaving this setting where it is. However, you could change it for a couple of reasons. The first is that maybe you can get your robot to respond even more quickly by lowering the lag…though we think you’ll overwhelm your NXT first. The other reason is that you may want to slow down your robot by increasing the lag. This can be used to simulate a laggy environment giving you drive practice for bad conditions. In any event, to change the lag simple put a number between 0 and 255 in the text file. Either have nothing or a simple RETURN/ENTER after the number in the text file.
mode.txt Sets the run mode to either tele-op or autonomous. mode_notepad
targetID.txt Sets the Bluetooth ID for the robot that the ChapR will pair with.
Type in the Bluetooth ID (including colons) on a single line.
canMMode.txt Turns on the ability for the ChapR to switch into “Match Mode”.
0 is false (meaning the ChapR CAN NOT switch into match mode, 1 is true (meaning the ChapR CAN switch into match mode). Either have nothing or a simple RETURN/ENTER after the number in the text file. Note: the default is 1 (matchMode on).
mConfig.txt Sets the timing parameters for “Match Mode”.
There are three “phases” of match mode that can be set: autonomous, teleOp and endgame. Setting any of these to 0 will skip that phase.
To set them, type the lengths (in seconds), in order, separated by returns. For example, the picture at right will set autonomous to 30 seconds, teleOp to 90 seconds and endgame to 30 seconds.

Important Notes!

The spelling of the names of the text files is extremely important – including the capitalization of some of the letters. The ChapR looks for these file names exactly, and if they are misspelled, it just won’t work!

When using a flash drive to configure the ChapR, make sure you have a strong battery! A new battery works the best. Reading flash drives takes a lot of power – at least a lot of power from the little ChapR’s perspective!

Flash drive configuration only works with Port 2 on the ChapR.  If you try to use Port 1, it won’t work and the ChapR will issue its angry sound.