Elektor has a long history when it comes to publishing data acquisition systems and loggers — the most recent project [1] proved very popular. The data logger we are proposing here is unique due to its simplicity and compact size; a microcontroller and a handful of common components are all it takes for hardware. This data logger is used to save the values of four analogue channels supplying any voltage ranging from 0 to 5 V onto a standard memory card (SD – Secure Digital).
Resistors
R1 = 470 Ω
R2,R11,R13,R15,R16,R17,R18,R20,R21,R22,R23 = 10kΩ
R3 = 22Ω
R4 = 56Ω
R5,R7,R9 = 3kΩ3
R6,R8,R10 = 2kΩ2
R12,R14,R19 = 1MΩ
R24 = 1kΩ
P1,P2 = 10kΩ preset
Capacitors
C1,C2,C3,C9,C10,C15 = 100nF
C4,C12 = 100μF
C5–C8 = 10μF
C11,C13 = 22pF
C14 = 5-25pF trimmer *
Semiconductors
D1 = 1N4001
D2,D3 = BAT81
D4-D7 = 5V1/400 mW zener diode
D8 = LED, 3 mm, red
IC1 = 7805
IC2 = TS2950-3.3
IC3 = MAX232
IC4 = PIC18F452, programmed, Elektor Shop # 070745-41
IC5 = PCF8583
Miscellaneous
S1,S2,S3 = miniature push button
JP1 = 2-way SIL pinheader with jumper
K1 = 2-way PCB-mount screw terminal block, 5mm lead pitch
K2 = 8-way SIL pinheader
K3 = 9-pin PCB-mount sub-D socket (female)
K4 = SD card connector
X1 = 32.768 kHz quartz crystal
X2 = 20 MHz quartz crystal
BAT1 = CR2032 Lithium battery
LCD = LCD display with 4 lines of 16 characters, e.g. DEM 16481
PCB, ref. 070745-1
Kit of parts, Elektor Shop # 070745-71
Project software (source code, hex file, PC program), file # 070745-11
Informative articles
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