Article

Data Logger “deLuxe”

The efficiency of simplicity

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).

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Materials

070745-PCB.pdf

070745-11.zip

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.

The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.

PCB

Download Gerber file: 070745-1.zip

Extra info / Update

Update: February 2, 2008

New firmware in zip file -11 (free downlolad).

Change log:

- Fixed spelling bug "SYTEM STOPPED" to "SYSTEM STOPPED"

- Fixed junk character displayed after the last second digit on the time text line

Correction: Febuary 9, 2009

For proper level conversion between the USB and the PIC microcontroller, the schematic and the parts list should be corrected to read:

R5,R7,R9 = 2kohm2

R6,R8,R10 = 3kohm3

These changes have been implemented in the Component List published on the project web page.

Component list

Resistors

R1 = 470 ?

R2,R11,R13,R15,R16,R17,R18,R20,R21,R22,R23 = 10k?

R3 = 22?

R4 = 56?

R5,R7,R9 = 2k?2 (corrected from: 3k?3)

R6,R8,R10 = 3k?3 (corrected from: 2k?2)

R12,R14,R19 = 1M?

R24 = 1k?

P1,P2 = 10k? preset

Capacitors

C1,C2,C3,C9,C10,C15 = 100nF

C4,C12 = 100?F

C5–C8 = 10?F

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