Arduino Thermal Camera

My recent arduino project was to build thermal camera on the cheap using an ir sensor and some pan/tilt hardware. If you look at the device picture to the left there is also acoustic range finder mounted to the top.

The device works by sweeping a grid of points and assembles the image piecewise. The output consists of two images: 1) an acoustic images which tells the distance to the objects in view and 2) a thermal image that gives the temperature of the objects in view. I use gnuplot to assemble the images. See the scripts below.

I plan on using the range finder to determine the spot size of the IR reader. The spot size scales by dh_o/dL=2sin(5). Where dh_o is the change in spot diameter and dL is the change in distance from the sensor to the object. The five is a constant based on the 5degree viewing angle of the IR sensor.

I got the idea for the project from this site: http://www.cheap-thermocam.tk/

 

List of materials: Arduino (http://www.sparkfun.com/products/9950)

Pan/Tilt Hardware (http://www.sparkfun.com/products/10335)

2x Servos, Medium (http://www.sparkfun.com/products/10333)

1" Square Cicuit Board (sparkfun)

Laser (http://www.sparkfun.com/products/594)

Laser Mount (http://www.sparkfun.com/products/8674)

Ultrasonic Range Finder - XL-Maxsonar EZ2 (http://www.sparkfun.com/products/9493)

Ir Sensor, 5FOV (http://www.futureelectronics.com/en/Technologies/Product.aspx?ProductID=MLX90614ESFDCIMELEXIS3003055)

Solid Cord Wire (Radioshack)

2x 4.7k Ohm Resistors (Radioshack)

Pin out board (Radioshack)

Plastic Photobox (Hobbylobby)

Assembly progression:1. Assemble Pan/Tilt with servos. Use medium servos because small was a little too under torqued for the tilt action (notice jerkyness in video). The servos require 5V.

2. Attached the Ultrasonic transducer to a proto board by putting a wire through holes and soldering on both sides. (holes should align on both boards) Position the ultrasonic sensor in the middle of the main board so the ir sensor will align with the center of the ultrasonic sensor.

3. Attached laser mount to Pan/Tilt hardware such that the two right angle mounting holes are on the top side to connect the board. I used the left over screws from the servo to connect the laser mount. I drilled a hole first that was slightly smaller than the screw thread diameter.

4. Push laser into laser mount all the way. Stop and mess with the laser and simple servo application.

5. Now run a 3V power line and GND line leaving some extra wire to play with. The ultrasonic transducer can take 3V or 5V (5V better resolution). The IR sensor can only take 3V. My build just uses 3V for both the ir and sonar.

6. Now put the ir senor in carefully and just solder the leads don't trim. Next run your 4.7K ohm resistors from the power to the opposite side of board above the ir sensor.

7. Now form the interconnects on the board.

8. Add three wires to go from board to arduino. There is one for the ultrasound sensor and two for the ir sensor.

9. Mount the sensor to the laser mount. Use the holes provided on the laser mount. I also used the extra screws from the servos and drilled out the matching holes on the sensor board. It is critical that everything is square.

10. Connection the laser wires to the 3V power (red wire) and GND (white).

11. Connect the two power wires and three data lines to a intermediate board (got one from radio shack and cut it in half with a coping saw). This intermediate board will allow you to transition to the arduino pins. I add male headers (3pins) to this intermediate board to accept the servo connectors. Thus, if I blow a servo I don't have to re-solder.

12. When using the intermediate board you can create a common ground.

13. Now, modify the plastic picture box to accept the servo on the top and wires to come through the top. I found the center of the top and traced the dimension of the servo on the top and drilled holes and coped out the hole. Then I drilled some holes to secure it to the plastic using the hardware for mounting provided on the servo. Additionally, I cut a rectangular section out of the side to accept the usb and power. I placed the arduino in the enclosure and traced the general shape and again used a coping saw to make the opening.

14. I added standoffs to the bottom of my arduino and just hot glued the stand offs to the enclosure and the bottom of the arduino.

15. Now feed wires from sensors through holes to the intermediate board and solder. Also add wires on the intermediate board to connect to the arduino.

16. I added hot glue to the arduino wires to make sure they don't pull out.

17. Now close everything up and add some hot glue to the edge of the enclosure to keep everything together.

18. Plug usb and power in and upload the following code.

http://diffusionht.blogspot.com/2011/03/thermal-cam-arduino.html

http://duino4projects.com/arduino-thermal-camera/