under the GPLv2. The library allows users to control a Lego NXT via bluetooth controller from within other C programs. The library provides low level control and high level abstraction. The library only runs on Linux. PyNXC PyNXC is a project which converts Python code to "Not Exactly C" (NXC) code, to download to Lego Mindstorms Robots. NXT-Python NXT-Python is a python module, which communicates with the NXT via USB or Bluetooth. It supports direct commands and several aftermarket sensors. LEGO Mindstorms EV3 Software The software which ships with the newer Mindstorms EV3 set can be used to program the NXT. At the moment, Bluetooth is not supported for the NXT, so programs must be downloaded via a USB cable. Physical Etoys Physical Etoys is a visual programming system for different electronic devices. It supports direct mode and compiled mode. C/C++ Interpreter Ch Ch is a C/C++ interpreter running C/C++ code to control Lego NXT or EV3. No firmware upload/download is required, no compilation is needed. A C/C++ code running in Ch can control either a Lego NXT, EV3, or multiple of NXT/EV3. Sensors and Actuators The Lego Mindstorms NXT 1.0 base kit includes: 3 identical servo motors that have built-in reduction gear assemblies with internal optical rotary encoders that sense their rotations within one degree of accuracy. The touch sensor detects whether it is currently pressed, has been bumped, or released. The orange Enter button and the gray right and left NXT buttons can be programmed to serve as touch sensors. In the NXT-G programming software, a value of 0 is given out when it is not pressed, and a value of 1 is given out if it is pressed down. The light sensor detects the light level in one direction, and also includes a LED for illuminating an object. The light sensor can sense reflected light values (using the built-in red LED), or ambient light. In the NXT-G programming software the sensor senses light on a scale of 0 to 100, 100 being very bright and 0 being dark. If calibrated, the sensor can also be used as a distance sensor. The sound sensor measures volume level on a scale of 0 to 100, 100 being very loud, 0 being completely silent. The ultrasonic sensor can measure the distance from the sensor to something that it is facing, and detect movement. It can show the distance in both