Table schema:
CREATE TABLE table_name_21 (sensor VARCHAR, camera VARCHAR, output VARCHAR, sensor_resolution VARCHAR, cpu_usage VARCHAR)

Question: What sensor has a resolution of 640x480 with small CPU usage, jpeg compressed output and a camera of sony playstation eyetoy?
SQL: SELECT sensor FROM table_name_21 WHERE sensor_resolution = "640x480" AND cpu_usage = "small" AND output = "jpeg compressed" AND camera = "sony playstation eyetoy"