Case #83 William Played A Mean Game of Go Fish!

April 24, 2006

Take down the house with this gadget. William's handheld controller provides the display of a monitored process deviation - but after hours it doubles as a card counter. (In either case, the algorithm is identical.) It works by adding or subtracting manually-entered "event" counts to a common 8-bit counter register. The value is subtracted from a predefined mean to generate the error or variation around the mean. This error "index" selects a display state sequence, continuously scheduled in an LED display. For William's complete instructions, click here .

Card Counter/Process Controller Parts List


Part Description

Allied Part #
1 Battery 2 AAA 729-5173
1 Battery holder Dual AAA 839-9989
1 Green LED 782-0045
1 Red LED 782-0030
1 620V 0.25W resistor 296-0039
1 Momontary button right angle 821-0330
1 Button Cap black 821-0391
1 Header jumper 518-0009
1 Perf board .010-inch centers pads/2sides 977-1250
Additional parts required: 8-pin controller MicroChip/PIC12C508A; 1 header, 3 pin, 0.10-inch centers, right angle (Molex/22-288033); Hookup wire, 30ga/solid/insulated (OK Industries/KSW30WR-0100)

For parts information, call (800) 433-5700, or go to

For William Grill's complete instructions and microcontroller code to build a handheld card counter/process controller, click here .

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