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Multi-Purpose 12-Key Capacitive Keypad
Vast improvement over flaky 1970’s touch controls
In this article we rebirth the touch key, but with 2015 technology meaning an AVR micro, clever software and a advanced board design. Time to throw in AVR micro power!
Components
The BOM (Bill of Materials) is the technically exhaustive listing of parts and other hardware items used to produce the working and tested prototype of any Elektor Labs project. The BOM file contains deeper information than the Component List published for the same project in Elektor Magazine. If required the BOM gets updated directly by our lab engineers. As a reader, you can download the list here.
Want to learn more about our BOM list? Read the BOM list article for extra information.
Component list
Component List
Resistors
Default: 5%, 0.1W, SMD 0603
R1-R12,R15,R16 = 1kOhm
R13,R14 = 220Ohm
Capacitors
C1-C12 = 22nF 10% 50V, X7R, SMD 0603
C13-C18 = 100nF 5%, 16V, X7R, SMD 0603
C19 = 4.7µF 10%, 6.3V, SMD Case R (0805), tantalum
C20 = 10µF 10% 25V, X5R, SMD 1206
Semiconductors
D1,D2 = LED, SMD 0805
D3 = PMEG2010AEH, SMD SOD-123F
IC1 = ATmega324PA-AU, SMD TQFP-44, programmed, Elektor Store # 130105-41
IC2 = NCP5501DT50G, SMD DPAK 3
Miscellaneous
K1 = 10-pin (2x5) pinheader, 0.1” pitch
K2 = 6-pin (2x3) pinheader, straight, 0.1” pitch
K3, JP2 = 2-way pinheader, 0.1” pitch
K4, K5 = not mounted, leave open
JP1 = 3-pin pinheader, 0.1” pitch
Single shunt jumper, 0.1” pitch, for JP1 and JP2
Bare PCB only, ref 130105-1 v2.1 from Elektor Store
Resistors
Default: 5%, 0.1W, SMD 0603
R1-R12,R15,R16 = 1kOhm
R13,R14 = 220Ohm
Capacitors
C1-C12 = 22nF 10% 50V, X7R, SMD 0603
C13-C18 = 100nF 5%, 16V, X7R, SMD 0603
C19 = 4.7µF 10%, 6.3V, SMD Case R (0805), tantalum
C20 = 10µF 10% 25V, X5R, SMD 1206
Semiconductors
D1,D2 = LED, SMD 0805
D3 = PMEG2010AEH, SMD SOD-123F
IC1 = ATmega324PA-AU, SMD TQFP-44, programmed, Elektor Store # 130105-41
IC2 = NCP5501DT50G, SMD DPAK 3
Miscellaneous
K1 = 10-pin (2x5) pinheader, 0.1” pitch
K2 = 6-pin (2x3) pinheader, straight, 0.1” pitch
K3, JP2 = 2-way pinheader, 0.1” pitch
K4, K5 = not mounted, leave open
JP1 = 3-pin pinheader, 0.1” pitch
Single shunt jumper, 0.1” pitch, for JP1 and JP2
Bare PCB only, ref 130105-1 v2.1 from Elektor Store
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