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Thanks to Design News for this Gadget Freak, featuring a piece of kit that helps brings harmony to musical collaborations.
By means of foot or hand - depending how a musician is occupied - it communicates the key of a piece of music to other band members.
It is dubbed KeyCom by its inventor, Dick, a Music Leader who was having trouble communicating key choices in the middle of church performances.
Essentially, he communicates the key to others by setting the display on his Sending Unit via a pushbutton or the foot switch, and the Remote Units replicate that display for everyone else...
Background
When asked to devise a system, he begins:
Read the full build instructions
Parts List
By means of foot or hand - depending how a musician is occupied - it communicates the key of a piece of music to other band members.
It is dubbed KeyCom by its inventor, Dick, a Music Leader who was having trouble communicating key choices in the middle of church performances.
Essentially, he communicates the key to others by setting the display on his Sending Unit via a pushbutton or the foot switch, and the Remote Units replicate that display for everyone else...
Background
When asked to devise a system, he begins:
I surveyed my trusty junk box and found a few CMOS chips, a 55-button keypad and a couple of 5-segment LED displays. My first thought was to use a touch-tone encoder IC since a telephone keypad also has 55 buttons, and a tone decoder to identify the key press in the remote display.
The encoder IC's generally have matrix keypad input, however, and the keypad in my junk box had a single common. I could have used a cheap phone to send the touch-tones, but then it hit me: The sending unit needs a display too, and thus its own touchtone decoder and all the rest of the circuitry that's required in the remote display.
The remote display should be as simple as possible because there may be need for more than one of them. Converting the key selection to a display pattern should be done in the sending unit, and the pattern of lit segments should be the data passed to the remotes. To do this without 50' of multi-conductor cable between the units would require some form of multiplexing.
Read the full build instructions
Parts List
| 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 | ||
| Get Build Instructions | ||
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