the most prolific authors were Daniel Meyer and Don Lancaster. Daniel Meyer graduated from Southwest Texas State (1957) and became an engineer at Southwest Research Institute in San Antonio, Texas. He soon started writing hobbyist articles. The first was in Electronics World (May 1960) and latter he had a 2 part cover feature for Radio-Electronics (October, November 1962). The March 1963 issue of Popular Electronics featured his ultrasonic listening device on the cover. Don Lancaster graduated from Lafayette College (1961) and Arizona State University (1966). A 1960s fad was to have colored lights synchronized with music. This psychedelic lighting was made economical by the development of the silicon-controlled rectifier (SCR). Don's first published article was "Solid-State 3-Channel Color Organ" in the April 1963 issue of Electronics World. He was paid $150 for the story. The projects in Popular Electronics changed from vacuum tube to solid state in the early 1960s. Tube circuits used a metal chassis with sockets, transistor circuits worked best on a printed circuit board. They would often contain components that were not available at the local electronics parts store. Dan Meyer saw the business opportunity in providing circuit boards and parts for the Popular Electronics projects. In January 1964 he left Southwest Research Institute to start an electronics kit company. He continued to write articles and ran the mail order kit business from his home in San Antonio, Texas. By 1965 he was providing the kits for other authors such as Lou Garner. In 1967 he sold a kit for Don Lancaster's "IC-67 Metal Locator". In early 1967 Meyer moved his growing business from his home to a new building on a 3-acre (12,000 m2) site in San Antonio. The Daniel E. Meyer Company (DEMCO) became Southwest Technical Products Corporation (SWTPC) that fall. In 1967, Popular Electronics had 6 articles by Dan Meyer and 4 by Don Lancaster. Seven of that year's cover stories featured kits sold by SWTPC. In the years 1966 to 1971 SWTPC's authors wrote 64 articles and had 25 cover stories in Popular Electronics. (Don Lancaster alone had 23 articles and 10 were cover stories.) The San Antonio Express-News did a feature story on Southwest Technical Products in November 1972. "Meyer built his mail-order business from scratch to more than $1 million in sales in six years." The company was shipping 100 kits a day from 1800 square feet (1,700 m2) of buildings.