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DIY Data Capture via Web Cam

Automate data collection with a camera and optical character recognition

4 min read
DIY Data Capture via Web Cam
Photo: Paul Wallich

A while back, I got a cheap wireless LaCrosse brand weather station, with sensors for temperature, humidity, wind speed and direction, and rainfall. The stand-alone display shows weather conditions using seven-segment LCD numerals. The box the station came in promised that it “Connects to your PC!,” which appealed to me because I’d be able to automatically log the data and pass it around my home network. Well, it turns out that this promise could be honored only if I had a PC of the precise operating system and vintage that the station’s USB-to-wireless dongle called for. I’d also need just the right version of some proprietary weather software. Unfortunately, my Macintosh setup met none of these requirements.

Sure, if I had access to an already working installation (and a lot of time), I might have tried reverse engineering the embedded hardware and software. In theory, I could have figured out what the weather-station components were telling the dongle, what the dongle was telling the PC, and what commands might be flowing in the other direction. Then, with some more work and time, I could have reproduced that conversation on a Linux or OS X box. But I didn’t have the access or the time.

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From WinZips to Cat GIFs, Jacob Ziv’s Algorithms Have Powered Decades of Compression

The lossless-compression pioneer received the 2021 IEEE Medal of Honor

11 min read
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Photo of Jacob Ziv
Photo: Rami Shlush
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Lossless data compression seems a bit like a magic trick. Its cousin, lossy compression, is easier to comprehend. Lossy algorithms are used to get music into the popular MP3 format and turn a digital image into a standard JPEG file. They do this by selectively removing bits, taking what scientists know about the way we see and hear to determine which bits we'd least miss. But no one can make the case that the resulting file is a perfect replica of the original.

Not so with lossless data compression. Bits do disappear, making the data file dramatically smaller and thus easier to store and transmit. The important difference is that the bits reappear on command. It's as if the bits are rabbits in a magician's act, disappearing and then reappearing from inside a hat at the wave of a wand.

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