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Common issues

So something isn’t working and you find yourself stuck, this page is here to give answers to common issues. If nothing here answers your question, please feel free to ask in the #technical-support channel on the discord.

Please specify upload_port while updating firmware / trying to upload firmware fails

This error indicates there is interference between your computer and the tracker. Check the following:

  1. Make sure your USB cable from the tracker is plugged firmly into your PC.
  2. Make sure that your USB cable is a data and charging cable (it is suggested you try other cables or devices with the cable).
  3. Make sure that your drivers are up to date.

Additionally, this can be caused by software hogging COM ports (VSCode and Cura can be the cause of this).

The SlimeVR Server won’t start

Usually this is caused by Java not being installed or issues with your Java installation. The installer linked in the Installing the server page should handle this.

The WiFi Settings window outputs ERROR

Try resetting your tracker, this may fix the issues immediately. If this doesn’t work, your COM port may be being hogged, which can be tested by going through the firmware update process in VSCode (as it has more verbose error messages). If this is the case, close any application that might be hogging the ports (VSCode and Cura are often the cause). If the issue persists, try connecting the tracker to a different USB port.

The WiFi Settings window outputs symbols and nothing else

There are two common causes that you should check:

  • Make sure that you have the right driver installed.
  • Check that your PIO firmware upload worked. If you have multiple firmware versions open in VSCode you will have to set the correct one to default to upload.

My tracker keeps flashing

This is intended behavior, the number of flashes lets you know the current status of your tracker. Check the top of the the setup page for more info.

My tracker never connects to Wi-Fi / are not appearing on the SlimeVR Server

The two common issues that cause this error are:

  • Make sure you are connecting to a 2.4GHz network, 5GHz networks are not supported.
  • Check your SSID for special characters. At the time of writing SlimeVR only supports network SSIDs that contain alphanumerical characters.

If all of this is correct, you can check your gateway’s list of connected devices to see if all your trackers are connecting. If a tracker is not connecting even after using the same firmware upload with hardcoded wifi details there are two additional steps you can check:

  • Check if your wifi has reached it’s maximum allowed wifi connections. You can test this by disconnecting devices and then trying to connect your trackers again.
  • If you hard coded your wifi settings in platformio.ini try connecting your trackers via usb and pushing new wifi details. You may find this either fixes your connection or provides you with additional details on why the connection is failing.

My aux tracker isn’t working

In order to make sure your aux tracker is set up, you need to specify it in your defines.h uploaded to the primary tracker’s firmware. Check the bottom of the section mentioning defining the pins on the configuring the SlimeVR firmware page. Alternatively, you should ensure that you have correctly soldered VCC to AD0 on your aux tracker IMU.

Sensor was reset error

Check your INT wire, there is either a bad connection or you have it connected to the flash pin. If you are building your tracker on a breadboard, your connections may be not firm enough and cause this error.

The trackers are connected to my wifi but don’t turn up on SlimeVR

Check that you do not have two copies of the SlimeVR server running, as only one of them will show trackers connected.

If only one server is running, this is most likely a firewall issue, go to SlimeVR Server folder and run firewall.bat as administrator.

If you are still having trouble, try manually adding the SlimeVR Server to your firewall.

  1. Go to Settings > Network & Internet then click on the text link Window Firewall (you may have to scroll down).
  2. In the firewall window, click the link Allow an app through firewall.
  3. Click the Allow another app… button, and then Browse… in the opened Add an app window. If your options are greyed out in the Allowed apps window, click the Change Settings button to allow changes.
  4. In the File name text box, type *.* and press enter before navigating to slimevr.jar in your SlimeVR server folder and select it (if you cannot see files in this folder, try typing *.* and pressing enter again to show all files).
  5. Click the Add button to add the file to your firewall settings.
  6. Finally, make sure both public and private check boxes are selected in the Allowed apps window before clicking OK to save the changes.

The trackers are connected to the SlimeVR server but aren’t turning up on Steam

  • Make sure you installed SlimeVR with the installer to have the right SteamVR driver.
  • Make sure the SlimeVR addon is enabled in SteamVR Settings > Startup/Shutdown > Manage Add-ons.
  • Make sure you have SteamVR Trackers clicked.

My trackers are bound to the wrong controllers in SteamVR

You have to set them to the right location within SteamVR. Refer to the setup page for more info.

Your trackers are drifting more than expected

Make sure that when you turn on your tracker, it’s lying on a flat surface. The sensors need to calibrate for 10-20 seconds in a stable environment.

My feet sink into the floor / I’m sliding a lot

This will be due to either your physical or bone length set up. Try:

  • Running autobone again.
  • Other suggested mounting points.
  • Adjusting your bone lengths manually by following the step shown here.

Trackers are moving in the wrong direction when I move

You may have specified a wrong IMU_ROTATION value in your defines.h file. Take note of which trackers are the issue and refer to the configuring the SlimeVR firmware page to get the board’s rotation right.


Created and updated by CalliePepper#0666, edited by Emojikage#3095, Spazzwan#0001