Red Light on ArmBox IQ

Hello, My Daughters got a VEX IQ Super kit for Christmas. We are new to robotics, but I’m in IT. We built the armbot from the instructions, and it mostly works. However, the green LED turns red and the bot stops responding. I have used the controller both wireless and tethered. I have checked to make sure everything is plugged in the right places and calibrated the controller. Sometimes if I restart the unit, the LED will turn green and allow the bot to run, other times I have to manually move the arm to get the green light to come back on. Any Suggestions?

Hi Neal,

We’re sorry that you have encountered this issue. To help get this problem resolved, we have a question first - which LED is turning red?

Robot Brain LED:
If the LED that is built into the Robot Brain is turning red, this means that the battery in the Robot Brain has too low of a voltage, which may not cause the robot to behave as expected. The resolution to this issue is to either recharge the Robot Battery (if you have the rechargeable Robot Battery 228-2604) or replace the AA batteries in the Robot AA Battery Holder with fresh ones.

Some more info:
You may notice that this LED in the Robot Brain can start green when a Robot is turned on, but can turn red and stay red when the robot is in use, but then revert back to green when the robot is rebooted. If this is the case, this means that your batteries are close to the threshold of being too low for continued use. When motors are heavily used or stalled, they draw more electrical current, which can cause the voltage of batteries to momentarily drop. If you have batteries that are just above the charge level to be good, they can drop into the red zone. If this occurs, the LED stays red to alert the user that their batteries need to be recharged/replaced soon.

Controller LED:
There are two LED lights on the Controller - the top Power/Link LED and the bottom Charge LED.

If the top Power/Link LED is red, this means that the rechargeable battery in the Controller needs to be recharged. To recharge the Controller, simply use the USB Cable and plug the Controller into your computer or a USB phone charger to recharge. The USB port on the Controller is only used for charging. When the Controller is charging, the bottom Charge LED will turn on. If the bottom Charge LED is red, this means the battery is charging. if the Charge LED is green, this means that the Controller battery is fully charged.

Touch LED:
The Touch LED is one of the sensors included with the VEX IQ kits. This sensor as an internal LED that can glow in any color, and includes a touch-sensitive surface that people can trigger with their finger, but won’t trigger if it’s hit by a robot or other inanimate object. If you are driving your Armbot using the built-in Driver Control program, some demonstration sensor functionality can cause this behavior.

In the Driver Control program, touching the Touch LED will cause its color to toggle between Green and Red. When the Touch LED is glowing green in the Driver Control program, the robot is temporarily disabled. Simply touch the Touch LED again to flip it to green.

If the Touch LED is turning red in the Driver Control program without touching it, simply unplug the Color Sensor. The Color Sensor has demonstration behavior in the Driver Control program to cause the Touch LED to turn red (and temporarily disable the program) if it sees red and re-enable function if it sees green. If you simply want to drive the Armbot for yourself, disconnecting the Color Sensor will resolve this issue. More information about this behavior can be found in Section 6.1 of the VEX IQ Control System User Guide.

If you have any further questions or comments, please contact our technical support folks at or by calling +1-903-453-0802 so we can help resolve this issue.


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