BEIJING, July 7 -- A month ago, Wu Yulu sold his "son" for 30,000 yuan (US$3,750).

    Wu Laowu (the fifth son of the Wu family), is, well, a robot Wu made with his own hands 10 years earlier.

    "I couldn't sleep well for several days after selling the child, but I had no other choice. I had to pay off my debts," said Wu, 44, a farmer from Mawu village in eastern Beijing.

    On his TV screen, he plays a video of Wu Laowu, serving tea and lighting cigarettes.

    In the past 26 years, Wu Yulu has made 25 robots, and "all of them were like my sons."

    Wu had a way with machinery and mechanics from childhood.

    "Sometimes when people passed by, I would think about the mechanical functions of walking," Wu recalled.

    Unfortunately, he could not pursue his passion through textbooks. He was one of five children in the family, and his parents could not support his education after he graduated from primary school in the mid-1970s.

    But a lack of formal education did not deter Wu from copying what he called "marvellous human motions."

    "At that time, I didn't even know the term 'robot'," Wu said. "But in my spare time from farming, I tried to collect everything that could be used in those movable things.

    "I loved to play with robots. The cleverer they became, the deeper the emotional link I felt to them. Later, I began to call them my sons."

    The wire, metal, screws and nails he used came from rubbish sites, or sometimes used parts from farm machinery.

    In the late '70s, Wu got a job at a farm machinery factory, and the small income helped him turn used sewing machine parts and some steel wire into his first robot.

    "Until now, I don't know the theory of physics, but I knew that electricity can drive motors and power can be transferred to the robot's hands and legs with levers and wires," Wu said.

    After his first robot turned out to be "disabled," Wu continued to experiment. In 1982, the first movable robot, Wu Laoda (the first son of the Wu), was born.

    Another video shows Wu Laoda as a coarse combination of steel wires and sticks without head and skin. He was destroyed in a fire seven years ago.

    Although Wu compensated for his lack of scientific knowledge with his talent and devotion, there were accidents, the first of which happened around 1995.