Category Archives: Linux

Making the legousbtower usb device permissions permanent

After using my MindStorms USB Tower on Ubuntu Linux for a while, I started noticing that the permissions on the /dev/usb/legousbtower1 device reverted to “root only” every time I rebooted or un- and re-plugged the device into the USB port. The permissions were like this every time:

crw------- 1 root root 180, 1 Oct 22 09:56 legousbtower1

Since I log on as user michiel, not root, I could not access the device, so NQC would complain about “Could not open serial port or USB device”. I found the solution on Adrian Smith’s Blog:

“For a more permanent solution create the file /etc/udev/rules.d/90-legotower.rules with the following contents,


You can use any group you’re a member of in place of <group>. You can find a list of the groups you’re a member of using ‘id -a‘. I used the group “adrian”. On a lot of systems there’ll be a group with the same name as your userid. This is fine so long as you’re the only one who’ll need access to the device. Otherwise you’ll need to find a common group or perhaps create a new one. By the way, the vendor and product ids in the udev rules file came from running lsusb.”

I used the group name “michiel” and it worked fine (I think it will work regardless  because it sets the mode to 666 which means read/write access for everyone anyway.

After creating that file, I unplugged the USB tower, plugged it back in, and presto there it was:

crw-rw-rw- 1 root michiel 180, 1 Oct 22 12:59 legousbtower1

Problem solved!


Configuring the LEGO USB Tower on Linux

If you are a Linux user and have a Robotics Invention System (RIS) version 1.0 or 1.5, you have a serial infrared (IR) tower, which is fairly easy to set up. RIS version 2.0 came with a USB tower however, and getting that to work isn’t as straightforward. Some of these steps might seem daunting to a novice, but if you follow them correctly you should be OK.


Current versions of the Linux kernel (2.6.*) include support for the LEGO USB Tower by default. There are many Linux distributions, and they’re not all configured the same way. Below instructions were created for Ubuntu version 12.04 TLS 32-bit, one of the most popular distributions at this time. Continue reading