Mark X Tricorder
The first "real-world" tricorder was developed by a Canadian company called the Vital Technologies Corporation in 1996. The scanner was called the TR-107 Mark 1; Vital Technologies sold 10,000 of them before going out of business in 1997. The TR-107 could scan EM radiation, temperature, and barometric pressure.
The TR-107 is properly referred to as a true "tricorder" due to a clause in Gene Rodenberry's contracts with Desilu/Paramount dating back to the time of the Original Series. The clause specified that if any company could find a way to make one of the fictional devices actually work, then they would have the right to use the name.