Auto Service Professional

FEB 2017

Magazine for the auto service professional

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14 | ASP February 2017 Technical your accuracy and dramatically reduce your diagnostic time. We're not going to describe specific tools here because there are just too many to cover. Instead we'll describe some of their more important features and how you can use them. Thermal imaging Everything in the world radiates energy. at's because molecules vibrate constantly, and those vibrations generate waves of elec- tromagnetic radiation. e physical distance between the waves (wavelength) depends on the amount of energy. When energy increases, the waves become closer together (shorter wavelength). e energy that creates visible light is radiated at wavelengths between 400 and 700 nanometers (billionths of a meter). e color red is the longest wavelength we can see, but the discovery of infrared energy (longer-than- red wavelength) in the early 1800s led to the development of the first tool for measuring energy as heat: the thermometer. By 1930, a television camera had been developed for the military that could detect infrared energy more directly and display it on a picture tube. Optical sensors developed in the 1980s made the technology portable, and micro-proces- sors developed in the '90s made it affordable for civilian applications. Today you can buy a consumer-grade pocket-size infrared camera for about $40. Professional-grade thermal imaging cameras started showing up on tool trucks almost 10 years ago, and they were expensive. Today these tools are available over a wider price range, and the price generally reflects the tool's features and capabilities. Some are well suited to automotive diagnostics, and while they are a significant investment, they are powerful diagnostic tools that can save time and improve the accuracy of your diagnosis. More and more techs are buying them and using them successfully. e most basic thermal imagers are consumer-grade models that connect to a smartphone running an Apple iOS or Android operating system. While these do not really compare to professional tools, they provide a low-cost way to explore thermal imaging before committing to a bigger investment, and they do offer some lasting advantages. First of all, they harness the process- ing power of the smartphone. While the image itself doesn't have the resolution of a professional-grade tool, the app offers a wide choice of imaging and display modes such as still, video, zoom, color range, etc. e more useful models have a regular optical sensor in addition to the thermal image sensor, and the app lets you split the screen to show both the optical and thermal images (see the opening illustration). Some models overlay a line drawing of the optical image atop the thermal image. It's still a low-resolution thermal image, but the added detail makes the overall picture more useful. Some consumer-grade imagers can be used with an extension cable. is lets you point the imager into inconvenient spaces, like under the dashboard, while viewing the image remotely on a smartphone or tablet. Even if you end up buying a professional thermal imager later, this small-sized tool can remain useful. Professional-grade thermal imagers cover a wide price range, but the least expensive models cost less than twice the price of the most advanced consumer-grade imagers. If you've ever used a non-contact Infra Red (IR) thermometer, this tool will seem familiar. Most models project a laser dot that indicates the area being scanned, and the display screen Some thermal imagers come pre-loaded with test procedures and known-good image libraries. Photo courtesy of Snap-on

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