Long ago, Casablanca Fan Company came up with a very innovative idea to control a lamp and fan. They interrupted the power line for a brief moment as it crossed through zero volts. Since AC has an up-and-down cycle, this gave them two controls. A TMS-1000 4-bit microprocessor was used to detect the power cycles and to control the fan blades and lamps.
The production line needed high-speed, automatic test equipment for their innovative fan control module. The test system is made from a microprocessor-controlled bed-of-nails fixture and a custom hardware platform.
A second generation of 8-bit designs was created that controlled two test heads.
With technical support from MTSI, within four months the production rate was over 1,000 units per month. Casablanca has sold millions of fans and has used multiple generations of more advanced circuitry as it became available. 4-bit, then 8-bit chips, with radio and power line signals. We are proud to have been a small part of their huge success.
In each generation, the operator inserts the fan module into the test head and lowers the lid. A magnetic switch detects the closure of the test head, energizing a latch and a test start sequence. The test is completely automatic, with failure codes and reports logged to a printer. The computer control is a custom microprocessor-based system developed by MTSI for use in dedicated testers.
The test equipment requirements were complicated by the 110-volt operation of the fan module. All tests had to be run at line voltage, requiring hazardous line voltages to be isolated from the operator. The resulting test takes only a few seconds to completely check the board and 4-bit computer. This is still in operation after 30 years.