AdruinoElectronicsOur ProjectsProduct Development

Micro Monitor

Author: Jared Bouck

Project Cost: $20.00 – $25.00

Est Construction Time: 1.5 – 2.5 Hr

Required Skill Level: You’re going to need to be able to solder…


This is a project I did a few years ago that I am dusting off for all you makers out there. This project is titled the Micro Monitor and it is a simple but powerful board. The core of this project is an ATMEGA 328 running the Arduino platform and an ENC28J60 Media Controller chip that creates a simple to use Ethernet capability for this board.

In addition the board includes a small suite of sensors that have been added to a tab on the side of the board so that the onboard sensors are more accurate, including a Temperature sensor, Humidity sensor and Light detecting Resistor. We also added in a push button that can be configured for anything you want (silence a audible alarm?), piezo buzzer, status led,  two Jumpers with pull down resistors, a 10K ohm Potentiometer (used for tuning thermal or light sensors?) and an additional RJ45 Jack that is designed to connect to a multiplexer for even more expandability.

This is a very easy to build, hack and use board and we have included everything you need to build this yourself! Don’t be afraid to remove or modify any parts you don’t need or want to use.

***** If you like this and would like to see us put together a board order or Kits let us know in the comments below. If we get enough feedback we will get a production run ordered.


 The Board:

At the bottom of the page you will find all the cad files for the chassis, eagle files for the board and example app code.

The board is roughly 2.5″ X 5.5″ and is almost entirely hole through components making it easy for the novice maker. The humidity sensor is the one Surface mount component but is extremely easy to add.



Board Etchings and Paths




micro diagram

Click the diagram above for a larger version.




Bill of materials. This should be about everything. I have used and prefer both Mouser and Newark, but shop around for the best prices and substitutions.

Component Description Part Number Quantity ID on board
Buzzer PC Mount 12mm 2.048kHz MULTICOMP – MCKPX-G1205A-3700 1 SPKR1
Capacitor – Ceramic 100nF NICHICON – UVR1A101MDD1TD 1 C4
Capacitor – Ceramic 18pF MULTICOMP – MC0805N180J500A2.54MM 4 C1, C2, C6, C7
Capacitor – Ceramic 100nF NICHICON – UVR1A101MDD1TD 2 C8, C9
Capacitor – Electrolytic 10uF MULTICOMP – MCRH16V106M5X11 4 C3, C5, C10, C11
Crystal 16MHZ MULTICOMP – HC49S-16-30-50-70-30-ATF 1 X1
Crystal 25MHZ MULTICOMP – MCRS025000F183000RR 1 X2
DC Barrel Power Jack 5mm jack, with a 2.1mm center pole CLIFF ELECTRONIC COMPONENTS – DC10A 1 Con1
Diode 1N4004 Y GENERAL SEMICONDUCTOR – 1N4004-E3/54 1 D1
Dip Socket 28 pin MULTICOMP – SPC15504 2 IC1, IC2
Ethernet Jack Mag-Jack Type Connector We will provide this component 1 J1
Ferrite Bead 6mm Axial EMI RFI Suppression FAIR-RITE – 2743015112 1 L1
Header Pins 2 pin MULTICOMP – 2211S-02G 2 H3, H4
Humidity Sensor HIH-4030 HONEYWELL S&C – HIH-4030-001 1 IC5
LED 5mm – Green MULTICOMP – MCL053GD 4 D2, D3, D4, D5
Mini Photocell PHOTOCELL 3K-11K OHM 5.10MM Advanced Photonix Inc – PDV-P8001 1 LDR
Programming Header 6 Pin Header MULTICOMP – 2211S-06G 1 H1
Push Button Right Angle MULTICOMP – MCDTSA6-5N 2 SW1, SW2
Quad AND Gate Logic Converter STMICROELECTRONICS – M74HC08B1R 1 IC3
Resistor – 1/4 watt 330 Ohm MULTICOMP – MCF 0.25W 330R 5 R4, R12, R13, R16, R19
Resistor – 1/4 watt 2K OHM MULTICOMP – MCCFR0W4J0202A50 1 R11
Resistor – 1/4 watt 10K Ohm MULTICOMP – MCF 0.25W 10K 6 R1, R2, R3, R14, R15, R17, R18
Resistor – 1/4 watt 49.9K Ohm INTERNATIONAL RESISTIVE – CMF1/44992FLFTR 4 R5, R6, R7, R8
Resistor – 1/4 watt 270R MULTICOMP – MCF 0.25W 270R 2 R9, R10
RJ45 Jack 8-Pin Connector Unshielded MULTICOMP – MTJ-881X1 1 J2
Temperature Sensor LM35 MICROCHIP – MCP9701A-E/TO 1 IC4
Trimpot 10K ohm TE CONNECTIVITY / CITEC – CT6V103N 1 P1
Voltage Regulator TO-220 / 7805a STMICROELECTRONICS – L7805ABV 1 U2
Voltage Regulator 78L33 STMICROELECTRONICS – L78L33ACZ 1 U4




Board Component Placement




Here is a shot of the top Silk Screen. This was a prototype board we had made with Advanced Circuits




And the back of the same board.




Here we have all the components mounted on the board.




Solder joints for you all to see!



Laser cut chassis. Pattern is below. We use our own laser cutter but this will fit on the small sheet if you use Ponoko.




This is the finished chassis and board mounted. The top of the chassis is designed to be easily removed with the 4 screws in the corners so you can get easy access to the header. If your going to do a lot of tinkering, just cut a hole for your FTDI cable.



The back of the Chassis




And the Bottom. I left the breakout board RJ45 jack with a snap out cover in the chassis design just incase you don’t use it.




file-sharing-folder Corel Draw Format

file-sharing-folder AI Format

file-sharing-folder DXF Format

Circuit Board:

Capture MicroMonitor.brd

Capture MicroMonitor.sch

Code Example:

ArduinoAPP-01 Arduino.pde

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