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A "Thermal Flashlight" is a DIY device which lets you do a kind of "light painting" -- [thermal photography](/wiki/thermal-photography). It produces a colored "heat map" overlaid directly onto a photo of a room. This is the simplest, cheapest, and to date, most effective way we have developed of measuring heat leaks or cool leaks indoors and outdoors. Simply put, the "flashlight" puts out redder light if it's pointed at something hot (default 75 deg F or more) and bluer light if it's pointed at something cold *(default 60 deg F or less). ### Parts The Melexis MLX90614 digital thermometer used in this kit can be found in a few places, at different price points: * [Adafruit.com](https://www.adafruit.com/product/1747) * [AliBaba.com](https://www.alibaba.com/trade/search?fsb=y&amp;IndexArea=product_en&amp;CatId=&amp;SearchText=Melexis+MLX90614+3V&amp;viewtype=) ### Assembly There are a few versions of the thermal flashlight: [notes:grid:activity:thermal-flashlight-assembly] ### Questions [questions:thermal-flashlight] **** ### Activities [activities:thermal-flashlight] **** ### Using a Thermal Flashlight To capture the light painting over time, we have been using timelapse photography or this [p5js.org sketch](https://editor.p5js.org/jywarren/present/dl7B2Upp-) ([source](https://editor.p5js.org/jywarren/sketches/dl7B2Upp-)) (or its inspiration, GlowDoodle), as seen in the top image on this page. * Within view of the camera or laptop, sweep the flashlight beam over the scene at a distance of about 12 inches. * Try to stay out of the way of the beam, and don't point it directly at the camera or it will create a "starburst" and may mess up your image. * It's helpful to wear dark clothing so you don't show up in the image as you're moving around. ### Building your own **Parts list** For a Thermal Flashlight with 3.6 V Melexis Sensor and Common Anode LED. * 1 [Melexis MLX90614](http://www.futureelectronics.com/en/technologies/semiconductors/analog/sensors/temperature/Pages/6314181-MLX90614ESF-DAA.aspx) non-contact IR thermometer (3v). Data sheet: http://www1.futureelectronics.com/doc/MELEXIS/MLX90614ESF-DAA.pdf * 1 [common-anode RGB LED](http://www.sparkfun.com/products/10820) * 2 4.7k Ohm resistors * 2 100 Ohm resistors * 1 180 Ohm resistor * 1 0.1 μF capacitor * wire * [a breadboard](http://www.sparkfun.com/products/7916) or circuit board &amp; soldering eqmt. * [Arduino](http://arduino.cc) * 9v battery and holder **Software** thermal-flashlight.zip Gist: https://gist.github.com/sdosemagen/1739961/ _Note: The goal of this file is to be a place to download everything without pursuing other links. If there are changes or updates please feel free to add and re-upload. If the file is missing anything, please comment below. You might notice that this is for the 5v Melexis, but it will work for either without issues. Alternative variations of the Flashlight can be made with a 5.5V Melexis Sensor and Common Cathode LED. For the 5.5 V sensor follow this diagram: http://publiclaboratory.org/notes/sara/2-7-2012/circuit-diagram-5v-melexis-sensor For the common cathode circuit board follow this diagram: http://publiclaboratory.org/notes/warren/2-11-2012/common-cathode-variant-thermal-flashlight-code Links to purchasing equipment: ### Consumable Parts * LEDs (1 per flashlight, but they sell as a pack of 25): http://www.sparkfun.com/products/10818 * Arduino Uno (1 per flashlight): http://www.sparkfun.com/products/11021 * Capicator (1 per flashlight): http://www.sparkfun.com/products/8375 * Resistor pack (this pack has a 180 ohm resistor which we found other packs not to have): http://www.eio.com/p-19326-velleman-kres-e12-pack-of-610-e12-series-resistors.aspx * 3.6 V infra red thermometer (1 per flashlight): http://www.futureelectronics.com/en/technologies/semiconductors/analog/sensors/temperature/Pages/6314181-MLX90614ESF-DAA.aspx. Data sheet: http://www1.futureelectronics.com/doc/MELEXIS/MLX90614ESF-DAA.pdf If you are starting an electronics kit from scratch: * a 40Watt soldering Iron (if you want it to be permanent otherwise duct tape or Velcro works temporarily) * hookup wire (solid not stranded- 22 or 24 gauge, you can get this at Radio Shack) * pliers called "wire strippers" to get the plastic wrap off the hookup wire (can get at Radio Shack) * solder for 40Watt iron, lead-free. * a breadboard (1 per flashlight). If you aren't soldering: http://www.adafruit.com/products/64. If you are soldering: https://www.adafruit.com/products/571. * a USB cable to connect the arduino to the computer via USB for power 5Volts (can get at Radio Shack) * household sponge for cleaning solder off tip * 9 volt battery with connector wires (can get at Radio Shack- 1 per flashlight) ***Cost: ~$40-$60*** **** ### Updates All research on PublicLab.org about the thermal flashlight project: [notes:thermal-flashlight] **** Several meetups have been organized to build and test thermal flashlights, at RISD (Providence, RI) and in Brooklyn, NY. We are organizing one now in Somerville, MA: * [Thermal Flashlight workshop](/wiki/thermal-flashlight-workshop) * [May 26 AS220 workshop](http://publiclab.org/wiki/may-26th-as220-thermal-flashlight-workshop) * [Thermal Fishing Bob presentation from NE barnraising](http://publiclab.org/notes/Kaya9804/06-09-2014/thermal-fishing-bob-presentation-from-the-ne-barnraising) ## Thermal flashlight heatmaps **** ## Custom thermal flashlight circuit boards Instead of building off of an #Arduino, it's possible to make a Thermal Flashlight using a custom circuit board. The circuit board files can be found here: https://github.com/Pioneer-Valley-Open-Science/thermal-flashlight ##Photos [![IMG_0779.JPG](https://i.publiclab.org/system/images/photos/000/003/132/medium/IMG_0779.JPG)](https://i.publiclab.org/system/images/photos/000/003/132/original/IMG_0779.JPG) [![IMG_0781.JPG](https://i.publiclab.org/system/images/photos/000/003/133/medium/IMG_0781.JPG)](https://i.publiclab.org/system/images/photos/000/003/133/original/IMG_0781.JPG) ...

Author Comment Last activity Moderation
donblair "Woohoo! Quick replies / queries: Do you have a link to the Visualight schematics? I should check them out, as Jeff was hoping to use their more..." | Read more » over 8 years ago
ajawitz "While I don't have a VisuaLight board to test on yet (I did just order what appears to be one of the last ones on Square?) I tried connecting the I..." | Read more » over 8 years ago
ajawitz "Awesome! This is what I was hoping to see and then some. I don't think I've ever seen something go from brainstorm to schematic so quickly! I was..." | Read more » over 8 years ago
donblair "Jeff -- ah, I see -- good point! I don't think I'm finding the proper Visualight schematic ... file:///home/chronos/user/Downloads/strip_02-schema..." | Read more » over 8 years ago
warren "Also, did you do those completely rad illustrations? " | Read more » over 8 years ago
warren "Wow, Don - fantastic and super speedy work! One reason I was interested in the Visualight board was the strength of the LEDs -- really super brigh..." | Read more » over 8 years ago
donblair "Alright, I've changed the design to use a 32u4 processor (like the Leonardo), based on the Adafruit Flora schematic. The layout isn't quite finish..." | Read more » over 8 years ago
donblair "Cool, I just added a screw terminal footprint, and a footprint for a resistor -- so now it's also a thermal fishing bob device (the board layout in..." | Read more » over 8 years ago
donblair "... this is sort of 'mission creep', but: if we add a footprint for a screw terminal and an extra resistor, we could connect up a thermistor -- and..." | Read more » over 8 years ago
donblair "Woohoo! Sure thing -- I'll ask Ray re: his process (and if he has any spare components lying about), and get an ETA on ordering a PCB (from OSH Pa..." | Read more » over 8 years ago
warren "Wow, so much progress! Don, if the PL nonprofit subsidized it, would you be able to order this and assemble a prototype to test it out? " | Read more » over 8 years ago
donblair "For what it's worth: I just added a header to the board to break out pins A0,A1,A2,D3, D5, D6, SDA, SCL (the I2C bus), VCC, and GND -- so that folk..." | Read more » over 8 years ago
donblair "So I went ahead and mashed up the Rayshobby design with the Sparkfun breakout -- note: Squarewear runs on 3.3V, so the 3.3V version of the IR chip ..." | Read more » over 8 years ago
donblair "Also, if it helps: there's an Eagle schematic for the associated breakout board for the IR device on Sparkfun, here: https://www.sparkfun.com/pro..." | Read more » over 8 years ago
donblair "This is cool! Quick aside: a friend in Amherst makes an open source board, "SquareWear", which is a wearable electronics device that has an RGB le..." | Read more » over 8 years ago
ajawitz "Its more that the Sparkfun Board presents a roadmap of sorts for integrating the Melexis Sensor directly into the flashlight board. Since the Virt..." | Read more » over 8 years ago
warren "Huh, i think you know a lot more than I do about ATmegas! We're thinking of doing our own modded version of the Visualight board in some quantity,..." | Read more » over 8 years ago
ajawitz "RE: Visualight Brightness- Interesting... This could be a major asset to one of my other projects- http://publiclab.org/notes/code4maine/01-15-20..." | Read more » over 8 years ago
warren "The biggest reason (for me) for using the Visualight was that it has a really bright RGB LED setup, aside from being compact. That was the stumblin..." | Read more » over 8 years ago
warren "Wow, very neat! The Visualight has USB built in, which is nice, and can also act as a keyboard device -- so Leif was talking about making it litera..." | Read more » over 8 years ago
ajawitz "UPDATE: See my new research note- http://publiclab.org/notes/code4maine/01-22-2014/thermal-flashlight-using-mlx90614-ir-evaluation-board-from-spar..." | Read more » over 8 years ago
ajawitz "Right now I think the goal would be to see any kind of range in the output so as to adjust the LED code accordingly. The current serial output abov..." | Read more » over 8 years ago
warren "Wow, very interesting. What would the serial output be like, ideally? just a stream of temperature values? Cool! Don't miss out on the Visualight..." | Read more » over 8 years ago
ajawitz "I added some changes to my documentation so as to clarify that I am not actually designing a new Thermal Flashlight build, but rather experimenting..." | Read more » over 8 years ago