Inexpensive DIY thermal imager
Thermal imager. A device for measuring the temperature distribution of surfaces, in a non-contact, visual way. As a rule, the temperature distribution map is displayed on the color display built into the thermal imager (or subsequent data transfer to the computer) as a color image, where red indicates the highest temperature areas, and black or blue. Low temperature areas. Such devices are very expensive (several thousand dollars) and allow you to determine the temperatures of dynamic (moving objects) in real time.
But, such functionality is not always needed, and this article describes the process of making a homemade scanning thermal imager, the cost of which does NOT exceed 200. The process of scanning an object Takes about a minute. This thermal imager is suitable for shooting static objects.
The device uses two servos (for moving horizontally and vertically), an Arduino controller (for processing signals and transmitting data to a personal computer), a laser module or a laser pointer (so you can see the scanning area), the MLX90614ESF non-contact temperature sensor module itself, a case and rotary device.
Examples of images of the surface temperature map obtained from this thermal imager:
List of used elements:
Laser Card Module. 8 (can be replaced with a laser pointer):
Search module on AliExpress, module on Sparkfun
Microsoft LifeCam VX-700 webcam
Rotary device (2 coordinates) Lynxmotion Pan and Tilt Kit:
Aliexpress 5-7, Robotshop.com 9.95, lynxmotion.com 9.95
MLX90614. Infrared thermometer in TO-39 housing. Datasheet PDF.
Sensor data can be read using SMBus or PWM. In our case, a sensor with the DCI or BCI index is used. Power supply 3V. Index I denotes the type of form factor, I. With a nozzle for a narrow field of view of 5 (see picture above).
Assembling the thermal imager
1. First you need to place the Arduino board in a case with a battery compartment
2.Using super glue or epoxy, secure the Servo Motors in the empty space in front of the Arduino.
3. Place the second Servomotors in the rotary device and fasten the entire structure to the Servomotors.
4. Now, you need to connect the MLX90614 to the Arduino. To do this, connect Ground to GND, Vin to 3.3V, SDA to pin 4, and SCL to pin 5. Also, set a 4.7k resistor from SDA to 3.3V, and the second from SCL to 3.3V. See diagram below.
5. Connect the Laser Card or laser pointer. The laser is needed so that you can see where the thermal imager is currently scanning.
6. After that, you need to install the webcam and orient it exactly with the IR sensor and the laser, so that they are oriented to the same point. This completes the assembly of the thermal imager.
Download the sketch for configuring the sensor. After uploading this sketch to the Arduino, open the Serial Monitor and press the button. The program will change the EEPROM settings of the sensor. This only needs to be done once. After you see the inscrIPtion “Finish” unplug Arduino from PC and plug it back in.
Download the main Arduino working sketch.
Additionally, you need the I2CMaster library.
The computer software is written in JAVA, so you need Java Runtime Environement. The software runs under Windows, Linux or Mac OSX in 32-bit 64-bit. However, if it runs under Windows 64 bit, then it is better to install the 32 bit version of JAVA. Download.
From aluminum tubes
A do-it-yourself camera trIPod can be made from a small piece of board, metal rods or aluminum tubes. The length of the tubes can be arbitrary, depending on how high you need the trIPod.
It is made in the following way.
- Draw two circles on the board, break them into 3 parts and make markings similar to the one shown in the following figure.
- Attach a narrow board to the markup and draw a rectangle in front of it, a little wider than the last. Measure down a few centimeters (depends on the overall dimensions of the trIPod) and draw another line. This will be the length of the part.
- Cut out all parts and sand them. Next, drill the side holes in the narrow planks and in the protruding parts of the base, then connect all the elements with bolts, as shown in the following photo.
- Cut the aluminum tubes to the same length. At their ends, you can put rubber tIPs from a rubber hose or heat shrink tubing.
- Drill holes in the tubes and screw them to the moving wooden parts of the base.
- Next, it follows from an aluminum plate (3 x 6 cm), cut a strIP and bend it in the shape of a letter “U”. Drill one hole in the center of the plate and 2 holes along its edges, then insert the previously prepared bolts into them.
- Drill a hole in the center of the wooden base and fix the previously made trIPod element.
Microscope from a camera
First of all, in order to make a microscope from a camera, you need to find a suitable lens. The best option is a lens from an old CD-ROM drive.
To attach a lens to a camera lens, you need to make a frame. It is made of foam, after which it is painted black for better light absorption.
On this, the manufacture of the microscope can be considered complete. But to use it you will need to make the simplest trIPod.
- To create a trIPod you will need: a plastic tube; a small piece of plastic (you can use the cover from under the disk case); 2 syringes 5 ml and 2 ml mounting bracket.
- Drill 2 holes in the tube. One for attaching the camera and one for the mounting bracket.
- Connect both syringes with a tube from a dropper, after filling a 5 ml syringe with water.
- Glue a square of plastic to the top of the syringe plunger (5 ml).
- Attach a syringe (5 ml) with pad to the tube using tape.
- Attach the camera to the tube.
- Attach the microscope to the table, place the element you want to examine on the plastic table.
- Next, turn on the camera and using the lower syringe (2 ml) Let’s focus the lens on the required object: when you press the piston, the table will rise, and when you pull the piston, it will lower.
The examples below show photos taken with such a microscope:
- LCD matrix Nokia E51;
- LCD matrix HP IPAQ hx2190;
- Human hair;
- Onion cages.
So you get a simple microscope with little or no investment. Its only drawback is the poor quality of shooting opaque objects, since external illumination is required. The above photo of the hair was taken with a backlit flashlight.
Crafts from the camera and for the camera
Almost every house has an old, unnecessary camera. It can be very ancient, film, or digital, from the very first lineup. Many owners of such equIPment are wondering: what to do with it? After all, it is a pity to throw it away, since at one time the technique cost a lot of money, and it is not possible to find its application in the modern world, at first glance. But craftsmen have long found a solution to this problem and make various crafts from and for a camera.
Thermal imager from a camera
A thermal imager is a rather sophisticated device capable of fixing infrared radiation emitted by surrounding objects at a distance. Basically, this device is used for repair and rescue activities, and also it is used by professional hunters to search for prey. A thermal imager is similar in design to a digital camera.
Despite its similarity to a digital camera, it will NOT work to make a full-fledged thermal imager from it. There are many tIPs on the internet for making a thermal imager from a camera. For example, it is advised to remove the infrared filter from the matrix, after which the Apparently the device will begin to fix the thermal radiation. But in practice, except for the breakdown of the digital apparatus, you will NOT get anything. This shows what will happen if you remove the filter from the camera sensor.
To make this GoPro trIPod with your own hands, you will need 3 identical shaving razors (you can have a floating head), a wooden block and a bolt with a suitable thread. First you need to make a small triangle from wood or thick plywood, then drill a hole in its center and insert a bolt into it, as shown in the photo below.
Further, to this triangle it is necessary to glue the machines using a glue gun. If not, then the razors can be screwed with small screws.
When the trIPod is ready, attach the camera to it.
Telescope from a camera lens
To make a telescope out of handy tools, you need two lenses: one short-focus, and the other long-focus.
The photo below shows the lens from the camera.
The main optics are made from a spectacle lens purchased from a pharmacy. The spectacle lens must have an optical power of 1 diopter, which corresponds to a focal length of 1 meter, and a diameter of 68 mm.
For the eyepiece, a lens with a focal length of 20 to 50 mm is suitable. It is defined simply: Place a lens under any light source and start focusing the luminous point, for example, on a sheet of paper. When the smallest point of light forms, measure the distance from the paper to the lens. This will be the focal length of this lens.
Below is a diagram showing the structure of the simplest telescope.
The telescope body is made of cardboard, one side of which must be painted over with black paint.
The paper should be wound onto a blank with a diameter equal to that of the lens, and then glue it together. You can use PVA glue. The main tube of the telescope should be 10 cm less than the focal length of the lens. The inner pIPe is made 30-40 cm long and must fit tightly into the main pIPe, with friction. Glasses are inserted together with a cap into the second tube.
As a frame for a large lens, you can use a case from a hand held magnifier of the appropriate size.
I inserted the caps with lenses into the pIPes, you get a homemade telescope. Sharpening is achieved by moving the tube with the eyepiece.
TrIPod for the camera
There are times when, when taking pictures, it becomes necessary to fix the camera in order to exclude vibrations and shaking. But there is not always a trIPod at hand, and many amateur photographers DO NOT buy it due to very rare use.
From a plastic bottle
This is an elementary way to make a camera trIPod. You will need a plastic bottle, a bolt, a nut and 2 washers.
Drill or pierce a bolt hole in the cover. Next, put a washer on the bolt, insert it into the hole made, put on another washer and tighten the nut.
For the stability of the entire structure, fill the bottle with water (you can pour sand), screw the bolt into the camera and screw the cap with the attached device to the bottle.
You will have a primitive trIPod made in 10 minutes. The disadvantage of such a device is that the camera can only be rotated in a horizontal plane, it will NOT work to raise or lower the camera.
“advanced” a trIPod from a plastic bottle is made in the following way.
- Prepare a plastic bottle, glue gun, nail, wood block, and inch bolt.
- In the neck of the bottle, it is necessary to make a cut, for example, with a grinder. You can also burn the grooves with a hot nail, as shown in the following photo.
- Next, clamp the nail in a vise and bend it in the shape of a letter “P”.
- Let’s make a small wooden block and drill a through hole in its center with a size slightly larger than the diameter of the bolt.
- On the other side of the bar, drill 2 blind holes to insert a bent nail into them.
- Add some glue to the side holes and insert the U-shaped piece into them.
- When the glue hardens, insert a bolt into the center hole and attach the block to the camera.
- Next, insert the U-shaped piece into the cut-out grooves on the neck of the bottle and tighten the cap.
- If you tighten the plug more, the camera will be held at any angle.
Camera as a webcam
Of course, you can make a webcam from an old camera, but not from any model. Some cameras already have a built-in Webcam function that allows you to use the device for THESE purposes. Therefore, to start communicating on the network, just connect it to a PC via a USB connector and install the drivers.
Cameras that do NOT have the Webcam function are divided into 2 groups:
- Devices that can work as a webcam, but this requires special software and cables for signal transmission;
- Devices that cannot work in streaming mode
To determine which group your camera belongs to, connect it to the TV via a cable that has a plug for connecting to the camera on one side, and one USB connector and 2 tulIPs on the other.
When connected to a TV through a yellow tulIP, you will see on its screen an image coming from your camera in real time. Cameras include photo viewing or not required. Live streaming from the camera means that such a device can be used as a webcam, only you need to configure the software.
To start the webcam from the camera with the computer, do the following.
- Install the correct drivers for the camera. You should also install some kind of webcam control software (SplitCam, ManyCam or WebCam).
- Disable the shutdown function of the camera when not in use. If possible, connect the camera to a power adapter to avoid draining the batteries.
- Turn off your computer and connect the yellow tulIP cable to it.
- Turn on your computer and start the capture software. In its window you will see the image transmitted by the camera.
- Open the utility settings (File Source) and Set your device as the recording source. Also assign signal parameters. If your internet speed is slow, you should reduce the quality
- Now you can test the camera in action. Open Skype and go to the program settings. Indicate in it that the installed and configured utility will serve as the signal source, and then make a call to someone.
Do-it-yourself thermal imager from a camera
Probably many people watched the movie Predator and a little jealous of the ability to see heat radiation, like the notorious alien. It turns out that this feature can be used not only for hunting, but also in many areas of production and medicine. And this pleasure is not so expensive. a thermal imager, and you can even make it yourself from a camera a la soap dish. How to do this, and where the device can be applied is the topic of today’s article.
What you can use a thermal imager for
In addition to special effects in science fiction films, the device finds the following applications:
- Leakage control of energy resources. since poor contact leads to heating of the conductors, the thermal imager makes it possible to easily identify this problem;
- Assessment of the thermal insulation properties of buildings under construction;
- As an alternative to night vision devices. for detecting enemy personnel and equIPment;
- In rescuers. for detecting fires, searching for people, possible exits from the premises and assessing the situation;
- In medicine. to identify people with fever in a crowd and to identify pathologies of the body, including cancer foci;
- In metallurgy and mechanical engineering. to get an idea of the heterogeneity of heating objects.
In addition to the above, the thermal imager is used in astronomical telescopes, in veterinary control and in night driving systems. In short, the range of its application is definitely not limited to hunting.
The princIPle of the device
Without going into the jungle of physics, I’ll tell you: all bodies with temperatures above absolute zero emit heat. In the middle infrared range (7-14 microns), not visible to the human eye, the maximum degree of radiation in bodies with a temperature of.50 to 50 degrees. The display of the thermal imager shows a color picture of the temperature difference of the studied surface. Color gradation occurs in the range of colors of the rainbow from purple to red, depending on the degree of surface heating.
Some industrial processes are interested in temperatures of several hundred degrees. The radiation wavelength in this spectrum is less. 3-7 microns. But according to the princIPle of operation, the instruments used for measurements, regardless of operating temperatures, are completely identical.
If the body has a temperature of about a thousand degrees, auxiliary devices are no longer needed, the glow is visible with the naked eye.
The operation of the device includes three main stages:
- Registration of radiation in the infrared range;
- Converting recorded data to digital values;
- Displaying the resulting thermogram, that is, a heat map of the surface of the observed object.
Modern devices allow making such transformations and obtaining images with virtually no delay, in real time.
How to convert a camera into a thermal imager
Actually, nothing really needs to be redone. Initially, the matrix of the camera perceives infrared radiation. Another thing is that manufacturers put in them so-called heat filters, which reflect or absorb infrared radiation falling on their surface.
In another way, this filter is called a thermal mirror, in a bourgeois version. hot mirror. As a result, the spectrum perceived by the camera’s matrix becomes approximately identical to what the human eye sees.
If you remove the IR filter from the camera, it will start working as a thermal imager. It is possible (but not required) to install a visible spectrum filter instead. As practice shows, it does not play a special role and practically does not affect the operation of the device.
In addition to the camera, experimental subjects (or victims. how the process will go) for making a miracle device can be:
- IR sensor.
I will not describe the technology of their alteration, since this is a completely different story. And the refinement technology is more complicated, and the costs are an order of magnitude higher.