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Cheap DAQ by LCD DMM OCR

Point webcam at multimeter's display. OCR the reading, plot as graph.
  (+12, -1)(+12, -1)
(+12, -1)
  [vote for,
against]

Rather than buying expensive "PC interface" versions of all my measuring gear, I'd like to simply point a webcam at the voltmeter, ammeter, thermometer, light meter, battery charger...

Since the 7-segment LCD font is so simple, I think it should be practical to have some software OCR the readings and record them over time, so I could plot the results or whatever.

The software that police and toll roads use to automatically read license plates of passing vehicles already has all the requisite compensation for varying brightness and contrast, and works well with a fixed character set. It could probably be adapted easily for this use.

Myself, Apr 28 2008

TopOCR, free OCR for webcams. http://www.topocr.com/mtutorial.html
If this were automated, it would be just about right. [Amos Kito, Apr 29 2008]

[link]






       Oh yeah, a feature to read analog gauges would be neat too, or to track the average brightness or color of certain pixels or image regions. (Perhaps from a second camera, operating with fixed image settings instead of auto-brightness.)
Myself, Apr 28 2008
  

       Excellent!
angel, Apr 29 2008
  

       This is a truly brilliant idea! Patent it before those guys at MaxCo Industries steal it. [+]   

       And who boned this without a why?
MaxwellBuchanan, Apr 29 2008
  

       I did once have to read a car's dashboard (Jaguar) for automatic production testing, including analogue tacho and speedo needles, using a camera.
The test rig provided stimulii, and the vision system had to provide go/no-go indications with quite tight constraints on the angles measured.
Certainly not cheap though. [+]
coprocephalous, Apr 29 2008
  

       Most gauges are basically voltmeters. I picked up a $60 multimeter at Radio Shack that has a computer output. I guess it only reads one at a time, why else wouldn't this suffice? I'd have to do some calibration to set it up, but in the end I'd get much more accurate readings. So is this just for when you can't get to the wires or specifically for old mechanical speedos?
MisterQED, Apr 29 2008
  

       I think there are lots of situations where this could be helpful. Does your multimeter also do stopwatchy stuff, or humidity measurements, for instance?   

       I just think that it's a brilliant idea to get any digital (or potentially analogue) meter to talk to a computer, at no cost.
MaxwellBuchanan, Apr 29 2008
  

       Point taken (+).
MisterQED, Apr 29 2008
  

       I'd use this for meter readouts, but it doesn't need to be exclusive to text. I could use it to identify/count birds at the feeder, watch for the mailman, or notify me when a storm is brewing.   

       //And who boned this without a why?//
[Max], it was auto-boned by some Cheap DAQ by LCD DMM OCR, no doubt.
Amos Kito, Apr 29 2008
  

       Bun. Cheap, easy and useful. Personally, I only score two out of the above three. Although my wife insists I only *look* cheap.
4whom, May 02 2008
  

       Could be a cheap solution for some simple applications, but unless you can read all your instruments with one webcam, a LabJack or similar might be cheaper and can monitor 8 voltages, count pulses, output voltages and digital signals to control instruments, etc. You need software to do anything useful (I use Labview, $100 from ebay), but that's also true of this idea.
Ford, May 02 2008
  

       BUN. DIS LIK TLA RMV PLZ.
RayfordSteele, May 05 2008
  

       I'd like to watch two voltmeters, an ammeter, an infrared thermometer (try finding one of THOSE with a serial port!) and the LCD display on a BC-900 battery analyzer, at the same time. Yes, I could go buy a C7000 analyzer with USB ($4500?) and hope that the data interface works with LabView, and wire up my own ammeter shunts for a LabJack, and build my own IR thermometer with a computer interface, (or just buy an Electrophysics Bcam, $14000 with their LabView software, $1800), and achieve the same thing. Or I could do it with a webcam or two watching the instruments I already own which cost a sum total of under $150.
Myself, May 09 2008
  

       I would be WAY into this, in fact I've been considering trying to get my water and natural gas meters mated up with some cheap webcams. It seems like reading them could be possible with GNU OCRAD. Initial experiments suggest I'll need to do some work on recognizing the fonts. :( Even just a simple "LED is ON" "LED is OFF" indicator would be very worthwhile to me. The cheapest of USB cameras are only $10 -- so it's worth a little work. Solid bun!   

       Later edit: Ocropus may be a better way to go for the OCR component. I think I also need a wee LED for lighting the gauge durign the photo.
eastpole, Jun 09 2008
  

       I put a web cam on my Dad's radon meter, with a 2 digit display, and used 'cron' to schedule a picture every 1/2 hour. I seriously considered doing some kind of OCR, but in the end it was easier to just print out a page with all the images on it and type the numbers in by hand. [+] from me, I'll sure use such software if somebody else develops it...
n81641, Jun 09 2008
  

       This is a very good idea: indeed, I had the same one! ;-) And I'm currently working on a python program which should turn any nokia phone into a data logger, just by putting it in front of the LCD you want to log.   

       YOu can follow project progress in this forum (in italian...) http://www.nokioteca.net/ home/forum/ index.php? showtopic=121150& st=0 &p=1060995& #entry1060995 (delete spaces!)   

       There's already a (quite) working source, which has some difficult with images brightess..
jumpjack, Jun 24 2008
  
      
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