The FIRST Tech Challenge (FTC) competition uses Bluetooth messaging to send driving commands to the LEGO Mindstorms NXT “brain” on the FTC robot. These commands originate from a computer (Mac or PC) in response to driver input from USB game controllers. Formatted data packets are sent to the NXT, which then processes them and directs the robot’s actuators (motors & servos) appropriately.
Although Bluetooth can provide very rapid data transfers, the particular implementation used on the LEGO Mindstorms NXT can cause unpredictable behavior when it’s used for remote control.
The attached document explains how significant latencies can develop due to the Blutooth message queue filling up.
One simple and effective way to eliminate this problem is demonstrated.
The attached zip file contains a descriptive document, Bluetooth processing VI and sample FTC Telop template.
Excellent analysis - this is a "must read" document for all FTC teams
I'd like to add that due to Phil's tireless work on this issue all of the FTC LabVIEW templates shipping with the software are written such to address and remove this lag issue.
Though I am not invovled with the FTC; perhaps I will be a mentor some day. I was having a the same issue with the NXT. Thanks for finding a fix to my problem and for the informative analysis! You saved me lots of debug time and $$$.
Thomas:-)