Problem
Our customer was purchasing custom keypad assemblies for a hand-held product. The manufacturer claimed a 100,000 cycle life for the buttons, but refused to supply test data to back up the claim. Our customer asked Alpha Omega to create a button tester that would determine the actual lifetime of the keypad.
Solution
Alpha Omega designed and constructed a pneumatic button tester that allowed the button push force to be adjusted through a wide range of pressures. The tester was controlled by a PC based program that allowed simple setup for different testing algorithms. A main assembly carried the computer interface, power supply, air pressure regulators and a large number of switchable valves. A connection plate allowed different test heads to be attached, allowing the assembly to be used with different test setups.
The keypad test assembly was machined to hold the particular device under test and attached to the main assembly with a mating connection plate. Small pneumatic cylinders provided the push force for the buttons, each tipped with a "test fingertip" to press the button. Actual button pressure was calibrated with a load cell.
Results
The button tester pounded many sample keypads into oblivion, verifying that the product would actually surpass 100,000 cycles on each button. After this initial use the tester was adapted to test a variety of products.
