Friday, June 24, 2011

Extech IR250 infrared thermometer disassembly and plans for thermal imaging

One of my ongoing projects is to develop a low-cost thermal imaging camera. In this video, I take apart an Extech IR250 infrared thermometer with the intention of grabbing an analog or digital signal so that I can record temperature measurements while using a scanning or image processing device to select portions of the scene being examined. Unfortunately, it looks like the analog circuitry is completely sealed inside a custom IC that is hidden under a blob of potting material. I'll remove the IR sensor from the board and build my own analog amplification and digitization hardware.






Common digital output IR thermometer sensor:
http://www.melexis.com/Infrared-Thermometer-Sensors/Infrared-Thermometer-Sensors/MLX90614-615.aspx

TPS334 sensor datasheet:
http://www.datasheetcatalog.org/datasheet/perkinelmer/TPS334.pdf

Analog Devices app note regarding thermopile sensors:
http://www.analog.com/en/all-operational-amplifiers-op-amps/operational-amplifiers-op-amps/products/technical-articles/using_thermopile_sensor_in_ir_digital_thermometers/resources/fca.html


Servo pan/tilt IR imaging scanner project:
http://www.cheap-thermocam.tk/

Redshift thermal imaging:
http://redshiftsystems.com/site

8 comments:

  1. Hi Ben,

    The potted IC looks a lot like the stuff i've seen on some of the digital bathroom scales i've taken apart (and currently use to get realtime weight of my beehive :)

    Weigh scales are pretty much the same situation, microvolt output in need of significant amplification.

    On my scale, the VPP was 'programming' voltage I think.

    Also i have an old DLP projector with a broken colorwheel if you want to play with it. I'm also in the bay area.

    -tmk

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  2. Do you know of any website where I can have detailed and clear explanations of device's inner workings as you do perfectly in this video ?
    Your posts are really very instructive !
    Thanks

    ReplyDelete
  3. Thanks for really great explanation. Please create a link where we could subscribe to your blog.

    ReplyDelete
  4. Krasnow... Краснов, вы русский?

    ReplyDelete
  5. Anonymous, use the "follow" button at the top of the page. I believe you can also find an RSS feed, but I've never used it myself, so I don't know the details.

    Tmk, thanks. I've always wanted to play with a DLP system. Youtube user tesla500 had a neat teardown of a DLP TV. It sure seems like the DMD could be used for all sorts of neat projects. Stay in touch.

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  6. Anonymous, my family name probably comes from Ukraine about four generations ago. I had to use google translate, as my language skills are pretty much limited to English.

    Anonymous, search the web for "teardown", and check my youtube channel for links to other youtube channels that feature instructive electronics stuff.

    ReplyDelete
  7. May be from Ukraine, but name is russian.
    Krasnow: "krasni" = "red" or "handsome"(literary)

    ReplyDelete
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