The Lumberjack - a Low Cost Modular Datalogger

Dataloggers in schools are expensive and often have proprietary software. In a bid to create a low cost alternative I created this from an arduino board, shield, switches and some wire for a total of approx $50 - $80.

It can utilise many of the sensors that Arduino produce for a fraction of the cost of some of the more expensive dataloggers.

The sensor can be powered off a powerpack and records all the data to an SD card so can be used as a datalogger in the field or in the classroom.

The code currently (is not efficient and could be improved) is limited to just a few different sensors. Hopefully I have labelled well enough that the program components to make it understandable.

Disclaimer: This was made in Australia and so prices are based on stores here.

General Tools

Glue gun

Soldering Iron

Wire cutters and strippers

Wire

Datalogger Housing

100mm PVC DWV Threaded Access Coupling ($5.50)

100mm PVC DWV Threaded Access Cap ($6.60)

Holman 100mm PVC DWV Push On Cap ($3.50)

5 Pin DIN PANEL Socket ($1.80)

3.5mm SPST Micro Tactile Switch x 6 ($0.95)

The Brains of the logger

Makerduino Uno ($29.95)

Electronic brick shield 1.2 ($15.95)

Power Switch (slider switch) ($1.65)

Arduino compatible SD Card Interface ($9.95)

2 x 16 LCD Display ($19.95)

10K ohm POT (I used a small trimmer ($4.00)

100k resistors x8 ($0.85)

Per sensor

Assorted sensors suitable for Arduino

5 Pin DIN Line Plug ($1.65)

Here are some photos of the pin guide as well as what I used for my project. My pins are identicle to the pin out guide, if yours isn't then you will need to ensure which ever pins you use, have the same properties.

Measuring up the spaces to fit the screen and then the layout of the keys is up to you. You will need to measure the screen and button size. Remember you can always remove material, you can't add it (easily)

Next the buttons are drilled in to line up with the lines on the LCD screen and a space for the SD card reader, 5 pin panel socket and buttons.

On the side of the PVC pipe you will need to cut a hole for the power to the arduino board

Inside of the panel the items were hot glue gunned

This is assuming you have some basic level of soldering skills.

If so, you will have a much better product than I did.

I'm assuming you will utilise the photos posted above as these have colour codes and examples of the wiring. To avoid congestion and scrolling page of doom, I chose not to place them in the paragraphs below.

Stick with us, this is going to get messy.

LCD Display

1. The first part we will do is the backlight for the lcd screen. By adding on a variable resistor, you can vary the brightness of the screen to how you would like it.
2. In the image the yellow wire is soldered onto the third from the right pad (I'll call it pad 3) and the leg by itself for the Potentiometer (POT).
3. The left and the right legs of the POT are soldered to the ground (black) and power (red) of channel 2 on the arduino board (if you are using a different board, make sure that your pins are the equivalent to the one I'm using.
4. You will need 3 black wires (the colours don't matter but I like to use black for earth) and connect them to LCD pads 1, 5 and 16 (labelled VSS, RW and K. These can go to any black pins as they all earth together.
5. Add a red (power) lead to LCD pad 2 (VDD) and connect that to the red pin on channel 0 on the arduino board
6. We are going to add a switch which will allow us to turn off the display, which will help save power if you want to run this datalogger out in the field for a few days/weeks
7. Run a wire (blue/green in the photo) from LCD pad 15 (A) to a small resistor and then that to one end of the slide switch. To the middle pin of the slider switch connect a wire and run that to the power pin on channel 4 on the Arduino board
8. Next you will need 6 wires and these are outlined where they need to go in the LCD Wiring table

(when I set this up it used a guide from another website - https://create.arduino.cc/projecthub/ThomTronics/easily-wire-a-16x2-lcd-222328)

Sockets

1. Don't connect the wires to the sockets until you are just about to put in the sockets, feed the wires through the holes (from inside of the housing to the outside) and the solder them to the sockets.
2. For our socket ports (5 Pin DIN PANEL Socket) we are going to wire on 3 wires to 2 of them and 5 to the third. The reason for this is that one of our sockets will be able to handle extra sensors (digital + analogue). The other two will be able to deal with most of the types that vary their resistance due to some sort of environmental factor (analogue)
3. The order for your sockets doesn't need to match mine but you do need to make sure that however you solder up your sensor to the plug that it matches to the socket.
4. For my sockets, I wired the single pin as the earth (black), the second as positive (red) and the third as the analogue (orange)
5. For the three sockets I used analogue pins A5, A3 and 2 (over on the other side). For the top right socket, it had an extra wire (green in the image) to pin 0 on the board.
6. At this stage I was finding it was difficult to fit in all the cables so I started using the board (with all the holes in it) and soldered the earth wires to the GND and also when I needed used the 5V for my red wires. These are always on and its the yellow pin where the brains are.

Buttons

1. The buttons had a straight forward layout. On one side of the buttons there are 2 legs and I wired in a white wire, on the other side there are 2 legs, one wire got a power (red) and the other had a ground (black) with a 100k ohm resistor between it and the button
2. The reds (5v) can attach to any 5v power location, the black can go to any GND location but the white wires go to the following places

The Wiring table can be found here

SD Card Reader

1. Similar to the other parts above. The SD card reader has the following pinout guide

The program, is detailed in the attached file. If you require assistance in setting up arduino, programming and uploading. There are much better tutorials available online to step you through the process.

You will want:

Arduino IDE found at https://www.arduino.cc/en/software

The program starts of by creating a home screen where you can scroll through and setup the 3 displays for the preprogrammed sensors

The bottom right is where the sampling rate is set up

The middle button starts and stops the program.

When the start button is pushed it will create a new csv file numbered sequentially (so it wont overright the previous data).

Here are some photos showing my mess of cables as well as how I mounted the slider switch for the display and the front panel turned on.