Gadget Freak Case #105: KeyCom Helps Keep Everybody in the Same Key

By: 
July 16, 2007

There was dissonance in the church when the pianist and other musicians had to hunt for the key their Music Leader was playing in. Dick's gadget took the guesswork out of the guitar, the meandering out of the mandolin and the pondering out of the piano. The Music Leader communicates the key to the others by setting the display on his Sending Unit via pushbutton or the foot switch, and the Remote Units replicate that display for everyone else. Now, they're all in one A chord (or F, or C, or...).

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Amt Part Description Allied Part #
1 7-Segment Display, Common Anode, Right Decimal, 0.8 inch 782-0570
1 7-Segment Display, Common Anode, Right Decimal, 13 mm 431-0048
16 1N914 Diode 431-0618
13 2N7000 N-channel MOSFET 568-0741
4 2N2222 NPN transistor 248-1004
4 1N4004 rectifier 266-0004
1 1N4742A Zener, 12V 1W 431-0332
1 CD4001 CMOS Quad 2-NOR 735-0960
1 CD4002 CMOS Dual 4-NOR 735-1065
1 CD4013 CMOS Dual D-flop 735-1325
1 CD4051 CMOS 8-ch MUX/DEMUX 735-0989
1 CD4070 CMOS Quad XOR 735-1002
1 CD4073 CMOS Triple 3-AND 735-1343
1 CD4081 CMOS Quad 2-NAND 735-1015
1 CD4093 CMOS Quad 2-NAND, Schmitt Trigger 735-1023
2 CD4099 CMOS 1 of 8 Decoder/Latch 735-2444
1 CD4516 CMOS 4b Up/Down Counter 735-1038
1 MC14526 CMOS 4b Presettable Down Counter 568-0877
2 RJ25 Right Angle jack w/ panel stops 374-5770
1 3.5 mm stereo phone jack (needs nut & washer) 283-0352
1 3.5 mm stereo phone plug w/ strain relief 283-3291
2 Push-button switch, NO, bushing mount w/ nut & washer 250-3241
Red Tail light tape (Automotive store item) Additional hardware & passive components, See Text
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