Troubleshooting

Corrupted file system

@author: Kegan Kawamura (kgnkwmr@berkeley.edu)

If for some reason the Odroid's file system becomes corrupt, the Odroid may not be able to boot properly. To fix this, it is necessary to repair the eMMC. Since the Odroid cannot boot, it is necessary to repair the chip externally.

1. Remove the eMMC from the Odroid, and attach it to the Transcend USB.
2. Insert the USB into a computer with a Linux environment. Open the terminal, and make sure that the USB is properly recognized. A useful command for this is lsblk. lsblk will display the different disks and partitions on the computer.

Once you've confirmed that the USB is recognized and found its name (it will likely be /dev/sdb), it is necessary to check which partition contains the Linux OS, which is where the corrupted file system likely is.

3. Run the command sudo fdisk -l in the terminal. This should display information similar to lsblk.
4. Under the eMMC memory, there should be a partition with "Linux" as its System type (likely to be /dev/sdb2). Now run fsck [/path/to/partition] (e.g. fsck /dev/sdb2). This should give you several prompts, and should automatically fix the file system. If it tells you that you do not have the permission to do this, try sudo fsck [/path/to/partition].

Once the repair is over, remove the USB and insert the eMMC back into the Odroid. Try booting the Odroid to confirm that the repair was successful.

Troubleshooting blinking red LED on ESC

Thanks to Vince Viola for writing this troubleshooting guide

Calibrating ESC

If the ESC blinks red and fails to respond to any command, do the following:

1. Check Arduino for burnt out ports
   • Switch ESC and servo ports
     1. If ESC LED stops blinking red, and it can receive motor commands, but not servo commands, then that port on the Arduino is probably damaged. Do not go through with the rest of the troubleshooting.
     2. If ESC LED continues blinking red, calibrate the ESC
2. Calibrate ESC:
   1. Unplug servo and ESC cable from Arduino, and plug them into the 2.4 GHz receiver. Servo connects to channel 1 (CH1) and ESC connects to channel 2 (CH2). Black wire faces toward car center, white faces torward outside.
   2. Turn off ESC
   3. Set remote control to the following settings below (other configurations may work), and then turn it on
      • Set ST (steering) to NOR (normal). In normal mode, turning the steering input frontward turns the steering wheel to the right
      • Set TH (throttle) to NOR (normal)
      • Set TH.D/R (sensitivity) set to 10
      • Set ST.D/R (sensitivity) set to 0
      • Set nobs on TH.TRIM and ST.TRIM (offsets) to line up with the white arrow
      • Set top switch on the side set to G
      • Set bottom switch on the side near the trigger to NP
   4. Hold down ESC set button, turn on ESC (while still holding set), and then immediately release the set button when the red LED light begins blinking. LED should continuously beep and blink red
      • If a big red light on the 2.4 GHz transceiver pulsing (not the red LED on the ESC), that means you do not have connection to your remote control. Turn it off and on a few times or move to an area with less wireless interference.
   5. Perform calibration procecure
      • Set throttle and steering both in neutral position (if not already) and press set button. ESC will beep and green LED will blink once
      • Pull back throttle all the way and press set button again. ESC will beep and green LED will blink twice
      • Push the throttle all the way forward and press set button again. ESC will beep and green LED will blink three times
      • Release the throttle. Green LED on ESC will blink and beep two more times.
      • After 3 seconds, you should be able to control the car with your remote control. Your ESC should be successfully calibrated.

Resetting ESC to default settings

1. Perform the steps in "Calibrating ESC"
2. Turn on ESC, and hold down set button until you see both the green LED and the red LED blinking many times. The red LED should then start to blink again on its own to show that the ESC is not calibrated.
3. Perform the steps in "Calibrating ESC"
4. ESC should now have default settings

Summary

If you can control the car with the remote control, but cannot send commands to the ESC with ROS, then the Arduino may be damaged. Try reflashing or replacing the Arduino.

If you are unable to control the car with the remote control in any way

• Ensure the ESC and Servo are connected to the right channels (Servo to CH1, ESC to CH2)
• Ensure the 2.4 GHz receiver has a connection (e.g. the big square red light is not pulsing on your 2.4 GHz receiver)

If the above methods fail, the ESC may be damaged, consider replacing it.