From BEAM Robotics Wiki
The famous Walkman by Mark Tilden
Mark Tilden began construction of Walkman 1.0 on Dec 15, 1993 and it was completed on April 1, 1994. It was made using parts from 4 "Walkman Pro" cassette recorders (in particular, the 151:1 ratio, rectangular Escap MU915L gearmotors from them) and an OTU/Pager motor based gearmotor (used for the waist). Walkman used a single battery, weighed 0.7Kg, had metal / plastic unibody construction, 2 visual and 5 tactile sensors, 8 sensor-processing Nu neurons, and 4 Nv neurons. Behaviors included high speed walking convergence, powerful environmental adaptive abilities, strong accurate phototaxis, 3 walking gaits (stop, walk, dig), and a backup/explore ability.
The legs on the motors had 360 degree freedom, which gave it great flexibility when trying different leg positions for climbing, pushing, and walking over different terrains. And there were rear-facing sensors, which made Walkman lift the corresponding rear leg somewhat higher than usual so it could clear whatever activated that sensor.
Sadly, all this is in the past tense, as Walkman was stolen out of Mark Tilden's Lab at the Los Alamos National Laboratories.]