Computers became affordable for the general public in the 1970s due to the mass production of the microprocessor, starting in 1971. Early microcomputers such as the Altair 8800 had front-mounted switches and diagnostic lights (nicknamed "blinkenlights") to control and indicate internal system status, and were often sold in kit form to hobbyists. These kits would contain an empty printed circuit board which the buyer would fill with the integrated circuits, other individual electronic components, wires and connectors, and then hand-solder all the connections.[16]