I have been researching a project which will help me with my understanding of electronics, networking, and programming. I decided to build an online thermometer which could be used in applications that need temperature monitoring. I currently work in a lab environment where I test, troubleshoot, and calibrate equipment which is installed in nuclear power plants . Each module must have a burn in time ranging from 24 hrs to 360 hrs per module under max load conditions. I could use my online temperature sensor to monitor the efficiency of the cooling system in the burn in area.
One of the modules that requires burn in. Yes that's 4 DMM's and 2 power supplies!!
I am going to go step by step in the build of the online thermometer.
I first need a network cable to connect my ethernet shield to a router ( if connecting straight to a computer the cable will need to be a crossover cable).
You will need;
Cat 5 or 6 ethernet cable
Network cable crimper/cutter
RJ-45 data plugs
Start by cutting desired cable length. Use strippers to cut about 1 1/4'' from the end.
Spread out twisted pair wires. I aligned them according to the T568B standard because it is more common in the industry. Here's a diagram of both options and a pinout of a crossover cable.
Make a clean horizontal cut using the cutters on my strippers. leave about 3/4" from the cut.
Insert the cut wires into an RJ-45 plug with white/orange wire on the left side. Make sure that the plastic insertion tab is facing down. Also ensure that the wires are pushed in far enough by inspecting the end. If you can't see the wire all the way to the end then push wires in further before crimping.
Insert the RJ-45 plug into crimper and crimp the cable (make sure that you crimp down on the network cable sheathing with the connector).
Now terminate the other end and you now have an ethernet network cable!!
Here's a part list for the Arduino online temperature thermometer:
1 Arduino Duemilanove, Arduino Pro, Seeeduino, or equivalent1 Seeed Studio Ethernet Shield or nuElectronics Ethernet Shield with prototyping shield
6 DS18B20 Dallas 1-wire temperature sensors (Note: not DS18S20)
6 4K7 1/4W resistors
Twisted-pair cable or alarm cable (minimum 3 conductors)
Here's the schematic for the Arduino board (click on image to zoom in).
Arduino Duemilanove PC board.
Here's the schematic for the ethernet shield (click on image to zoom in).
Seeed Ethernet Shield pc board.
The great thing about the Seeed ethernet shield is they leave room on the board to terminate wires and components. However the version that I got will still require a breadboard for some external components. I don't mind thought because I love working with breadboards!!
The temperature sensors will need a +5 VDC, Ground, and Data wire connected to work. I will need to terminate each data line accordingly from the ethernet shield:
sensor A = digital 3
sensor B = digital 4
sensor C = digital 5
sensor D = digital 6
sensor E = digital 7
sensor F = digital 8
I skipped the first few pins and started with 3 because 0 and 1 are used for the serial connection to the host. Pin 2 is used by the Ethernet shield to communicate with the arduino as seen in Figure 1.
I started out by soldering my +5VDC wire so I can have for the +VCC on my breadboard. For the wire I just used some network cable without the sheathing.
I then soldered my ground wire and then my data wires 3-8. Make sure to clean each connection with acetone or alcohol to remove any excess flux.
There we go, clean and simple.
Now lets terminate the +5VDC and Ground to the breadboard from the ethernet shield.