In this project I will show you how to build a digital laser infrared thermometer with a custom 3D printed enclosure!
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Step 1: Intro
Infrared thermometers are widely used in many work environments to determine an objects surface temperature. Often times in a machine or electronic circuit, rising temperatures are one of the first signs that something is wrong. A quick non-contact check with an infrared thermometer can let you know what is happening with the temperature of a machine so you can shut if off before it causes permanent damage.
Infrared radiation is just another type of radiation that exists on the electromagnetic spectrum. We cannot see it but if you were to place your hand near a something hot like a stove top, then you would be feeling the effects of infrared radiation. All objects emit energy in the form of infrared radiation. Most handheld thermometers use a lens to focus light from one object onto a thermopile which absorbs the IR radiation. As more IR energy is absorbed, the hotter it gets and the heat level is converted into an electrical signal which is eventually converted to a temperature reading.
I was working on a circuit the other day and I had a component that was getting extremely hot. I wanted to know the temperature of the component but since I do not own a infrared thermometer I decided to build my own. It has a custom 3D printed enclosure so anyone can print it and assemble right at home.
It is a simple project and could be used as a great introduction into sensors, 3D design/printing, electronics, and programming.
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Step 2: Components Needed
The components needed for this project are below:
1. Momentary Button Switch Amazon
2. Resistors (5K Ohm, 200 Ohm) Amazon
3. 5V Laser Amazon
4. Arduino Nano Amazon
5. On/Off Switch Amazon
6. OLED 0.96" Screen Amazon
7. GY-906 Temperature Sensor (or MLX90614 Sensor with proper capacitors/resistors) Amazon
8. 9V Battery Amazon
9. 3D Printer/Filament (I use Hatchbox PLA from Amazon)
Disclosure: The amazon links above are affiliate links, meaning, at no additional cost to you, I will earn a commission if you click through and make a purchase.
Step 3: GY-906 Infrared Temperature Sensor
I used a GY-906 infrared thermometer sensor which is a breakout board for the MLX90614 non-contact infrared thermometer by Melexis.
The breakout board is very inexpensive, easy to integrate, and the breakout board version comes with 10K pull up resistors for the I2C interface. It comes factory calibrated with a range of -40 to +125 degrees Celsius for sensor temperature and -70 to 380 degrees celcius for object temperature. The accuracy of this sensor is roughly .5 degree celcius.
Step 4: Electronics
Now that you have gathered all of the required components, it is time to start assembling everything together. I would recommend wiring up everything on a breadboard first and then once everything is functioning properly go ahead and solder everything up on a perf board.
On the left we have our laser with a 200 ohm current limiting resistor being driven from Digital Output 5. There is also a standard momentary push button that is connected between 5V and Digital Input 2. There is a 5K pull down resistor so that when the switch is open, the input is not floating and instead will be set at 0V.
On the right we have our main On/Off switch which connects our 9V battery to the VIN and GND pins of the arduino nano. The OLED display and GY-906 infrared temperature sensor are both connected to 3.3V and the SDA lines are connected to A4, and SCL to A5. The oled display and GY-906 already have pull-up resistors on the I2C lines.
Step 5: Programming
I will assume that you know how to program your arduino nano but if not, there are many great tutorials available online.
You will need to install the following libraries in order for the code to compile.
1. Adafruits SSD1306
2. Adafruits MLX90614
The program is constantly reading temperature data from the MLX90614 but is only displayed on the OLED when the button trigger is pressed. If the trigger is pressed, the laser also turns on to help identify which object is being measured.
Step 6: 3D Design/Print/Assemble
I designed the scale in Fusion 360.
In the base of the thermometer, there is room for a 9V battery, On/Off switch, and our trigger mechanism which is just a simple momentary push button. The base cover will snap into place. There is a hole to route the wiring for the base components into the top section of the thermometer.
There is an opening for the .96 inch OLED display and a front section on the tip of the thermometer for your laser and your MLX90614 sensor. Both the laser and sensor can be press fit into the hole. The top section is for the arduino nano and I will be honest, I really underestimated the amount of wiring I needed to connect up in the small amount of space. Alot of wires were pulling lose when I pushed the arduino nano into the small space so I ended up using a glue gun to hold the wires in place while pushing the nano inside the enclosure. I always put my arduino nano on standoffs just in case I want to reuse it for a project later down the line, so the standoffs took up alot of extra room that wouldn't be needed if you permanently soldered it on a perf board. Nevertheless, eventually I got everything wired up and in the enclosure, so then I press fit the top cover on.
Printing this is kind of tricky to get it to look great, as the main base I printed with the oled screen side faced down. The angle for the OLED screen is fairly high so I printed with supports on the build plate but that makes the surface look less than perfect. It might just be an issue of my printer and I am sure it is possible to get it looking great if you dial in your printer settings but I didn't really care to much as this is a tool.
Step 7: Test It Out!
Now that you have the laser infrared thermometer all assembled and programmed, it is time to test it out!
Push the power button, wait for the oled display to load up, and enjoy your new thermometer. Please consider subscribing to my youtube channel to support me and see more projects/videos. Thank you for reading!