Hi, we’re having a problem where our vex robot loses connection. We had a competition this weekend where the robot dropped connection repeatedly in almost every one of our matches. It is intermittent since we did have 2 matches where it worked for the entire match. We’ve been able to reproduce the problem at home now though not as reliably as in competition.
Here is the sequence:
Power up the robot:
Robot Game Light - yellow fast blink
Robot Vexnet Light - yellow slow blink
Some seconds later:
Robot Game Light - Yellow fast blink
Robot Vexnet Light - Yellow fast blink
USB Key - blue light comes on
Turn on Joystick and connect:
Joystick robot light - Green slow blink
Joystick Vexnet light - Green fast blink
Robot robot light - Green solid
Robot Vexnet light - Green fast blink
Sometimes immediately after connection (i.e. before you can do anything with the controls), or sometimes after driving for a few seconds:
Joystick - all lights flash red very quickly and the joystick appears to start its sequence over
Robot - slow blinking red vexnet light
Here are things we’ve tried to do to fix the problem:
- Verified that we have a fully charged backup battery installed
- Fully charged robot batteries
- Tried a test with the cortex wifi key on a USB extension cable, even moved a couple feet away from the robot (actually seemed worse)
- Tried using a different joystick (paired the new joystick with the cortex)
- Tried exchanging wifi keys with another team
- Used a USB tether cable to the robot and was able to operate the robot continously.
From the Cortex manual, the joystick flashing all lights red would indicate a reset (I assume of the cortex or does it mean that the joystick reset?). The slow red blink of the cortex vexnet light indicates “Fault: User Microprocessor Issue”.
Our code is a very simple EasyC program, no autonomous and only a few blocks; an arcade drive block and a few joystick to motor blocks, no logic, no loops other than the main “while (1)” loop.
Any help you can provide would be greatly appreciated! We have another competition in 2 weeks.