It is well-known that walking offers many health benefits for everyone, especially for older people who need to maintain mobility and independence coping with declining of functional capacity. In this paper, we present the design of a humanoid walking trainer that has to monitor and encourage walking in the elderly. This design is based on our target users' preferences. We present as well a preliminary walking experiment that was carried out in order to test the accuracy of the gait data obtained from the laser range sensor, which is positioned on the robot, during motion.