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Troubleshooting

Why is the Chronos Wi-Fi car not working? Here's a troubleshooting guide to resolve the most common errors.

Checklist for common issues

  1. Do the LEDs light up?
    If not, there's a power issue. Check that the battery polarity is correct and that the batteries are sufficiently charged.
  2. Is the status LED green?
    If not, the car is not ready to operate. Check the status overview to see what the LED indicates.
  3. Does the car connect to Wi-Fi?
    If the LED is green, the car connects to Wi-Fi. If it turns purple after booting, the car might not be able to connect. Check the configuration interface if the correct SSID and password are set.
  4. Are you connected to the same network as the car?
    One of the most common issues is unplugging the Ethernet cable from the router to your computer.
  5. Does the car receive commands?
    If the car is green but does not receive commands, check if the IP and port in the configuration interface match the host computer's port and IP in the wifi_com.yaml / the ROS parameter server. Usually, this manifests as messages on the ROS console similar to Cannot send packet since no car is connected!.
    • Check if the IP and port in the configuration interface match the host computer's port and IP in the wifi_com.yaml / the ROS parameter server.
    • Check if you receive packets from the car (rostopic echo /[car_namespace]/imu).
    • If the LED turns blue when you start an experiment, the car receives the commands. After you quit the experiment, the LED turns green again.
  6. The car does not steer well.
    • Open the config interface and move the wheels manually. Observe if steer trim point and slope seem sensible.
    • If the steering oscillates, remove any I/D gain and reset the steer P gain to about ~0.3 – 0.5.
    • If the car does not steer enough / hit corners, increase the steer P gain and lower the steer slope if needed.
  7. The performance seems otherwise degraded.
    • Check the battery voltage on /[car_namespace]telemetry/battery. If it drops below 4.4V, the car might not operate correctly.
    • Check the local environment for other interference. Run rostopic hz /imu to see if the data is received at a good rate (250 Hz is nominal).
  8. The car stops and its LED turns red.
    Sometimes, a low battery voltage can lead to brownouts. A protection feature in firmware >=v4.5 will stop the car until the batteries are switched or the microcontroller is reset using the ESP_RST button.