The new open-source Matlab/Simulink toolbox called RT-MaG presented here generates reliable standalone robotic applications running on real-time embedded Linux targets such as tiny Computers On Module (e.g., Gumstix boards). This toolbox gives direct access from Simulink to the main communication drivers classically used in robotics: network interfaces (via UDP), asynchronous and synchronous serial port interfaces (RS232, SPI), Pulse-width-modulation (PWM), general purpose input-output (GPIO) and analog-to-digital converters (ADCs). A Simulink model is automatically converted into a standalone multi-task program, which guarantees a repeatable execution time within each sampling time. The toolbox includes efficient debug modes which detect problems such as unsuitable configurations and hardware failure. The main features of the toolbox and its structure are described here. We also discuss the real-time performances and I/Os delays and show that a control loop can be implemented at frequencies of up to 1kHz. The tests performed show that RT-MaG can be used to efficiently implement all the control laws involved in stabilizing a quadrotor.