EDM (Hewlett-Packard 3800B)
"3800B DISTANCE METER HEWLETT. PACKARD SERIAL NUMBER 1141A00291" and "MADE IN U.S.A. PATENTS PENDING."
25 inches wide, 17 inches deep, 8.5 inches high
Hewlett-Packard introduced their first EDM on October 7, 1969, describing it as a "new, low-cost instrument that uses an invisible beam of infrared light to accurately measure distances up to two miles." It weighed 17 lbs (the separate power pack weighed an additional 13 lbs), and used a gallium arsenide diode to generate infrared radiation of 910 nanometer. According to William Hewlett, the idea for this instrument originated in 1965 as he watched a surveyor in Afghanistan using a European EDM and was struck by how long it took to set up the instrument. The process of modulating the light beam seemed especially arduous. "Surely," he thought, "HP technology--particularly in the area of photo-diodes--would have some contributions to make here." Paul Stoft, director of H-P Electronics Research, sketched the block diagram for the new instrument; Gregory Justice headed the development team. The new instrument, known as Model 3800, was introduced on October 7, 1970. The basic design was covered by a patent (#3,619,058) granted to William Hewlett and Gregory Justice on Nov. 9, 1971, and assigned to Hewlett-Packard.
Advertisements announced that the HP-3800 cost "just $4,110," and was so simple to use that costly training time was cut to less than 15 minutes. The 3800A had a range of 10,000 feet, with readout directly in feet; the 3800B had a range of 3 km., with readout directly in meters. By September 1971 there were over 2,000 units in use in the United States and Canada. The National Geodetic Survey transferred this unit to the Smithsonian in 1986.
Ref: Press release dated October 7 , Hewlett-Packard Company Archives.