The paper describes a sensor-based virtual Brain-to-Machine Interface (BMI) that allows walking at will by certain complete thoracic-level paraplegics using neuromuscular electrical stimulation (NMES). The multi-sensor system is walker-mounted, using a reciprocal walker. The sensors communicate electromagnetically (via Bluetooth microchips) with the NMES stimulator. This virtual interface (BMI) facilitates at-will walking, avoiding any brain electrodes or implants and requires no manual switching to initiate any step during walking. It is based on observing the elements of steps taken by paraplegics using the Parastep NMES system at the author’s lab. Based on these observations, a set of sensors is employed, to detect patients’ intentions and trigger NMES stimulation pulses accordingly, to result in walking at will. The resulting sensor data is shown to disallow unintentional steps while requiring only natural movements and avoiding any unnatural or pre-trained body or limb movements.