Ultrasonic Distance Measurer DM220  - Page 1
Forum section: electronics / general

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 25, 2010, 03:50:21 pm
content: Today I got my Ultrasonic Distance Measurer DM220 ,I had selected it, very carefully , got very impressed of the large dual lines display,Plus the price , that was just a bit higher than the ultra cheap ones. ( Ebay )The manufacturer brand name is missing, and I was a bit skeptic for few minutes,after testing it , by making lots of measurements , and verifying the results with an tape meter ,now I can proudly show-of a bit , about it ..Its big in size as device , but it is so , because in some measurements it must stand alone in the ground.I scanned the tiny in dimensions Users manual , so to be able to read it ..What I liked most as function , is the one that you can take multiple measurements,and its one are added at the total length.My need was to be able measure in door , and find out the length of the cables that I need, so to run across the room , vertical or horizontal .SummarizeGreat device , accurate , a bit bulky , easy to read , many options.Easy to use , but some training cycle is needed , so to learn how to place it correctly in the space for proper measurements.Pictures ..

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 25, 2010, 03:52:20 pm
content: Users manual.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 26, 2010, 07:08:46 pm
content: Today I got this meter at the factory that I currently work,For further extreme testing.In there, there are lots of big and tall buildings ,so it was an large scale test area ..Just one of the 8 major “ work shops “ in it .Its 80 meters long , 25 meter wide , and 16,34 meter tall .. (crane bridges moving around in it)Well I have mixed feelings , about my findings ,As I discovered the true capabilities of those ultrasonic devices.This technology are based on sound , the device its an sound source of 40KHz ,The returning “ reflected “ sound , it’s the measured portion.But the “ reflected “ sound , in order to be reflected , it must hit on something that reflects the sound back .So I tested the meter on several type of surfaces .And found the limits .The good part about the meter , are that if it did not gets an specific amount of reflected sound , it does not give an reading at all .So there is less chance to get an false measurement , at the worst scenario ,You will get an “ error “ message from the device , and no numbers.And now the data of my tests .1)Perfect finished wall and painted = 19.90 meters Max detectable distance.2)Metal large doors - full metal surface = 11 meters Max detectable distance.3)Wall covered with tiles = The most lovable surface for measurements by the. meter … my testing area was like 12 x 12 meters , and as I said the meter loved the tiles .5)Wall with common red bricks = 10 meters Max detectable distance.6)Wall with covered with plaster , but with the technique of “ Sprayed plaster ,By machine …. Its full of uneven spots , looks like an sponge , and it was the worst material for this meter , the detected distance dropped to just 7 meters .Extra remarks …This meter are suggested to be used at fresh finished buildings,That they are still totally empty ( no furniture ).When the measured space has objects in it , you must do several testing measurements, so to find the most clear optical line , across the room.The only fool proof measurement with it , are the distance between the floor and the ceiling .But for my taste , it’s the most important than all , and the most hard to make with any other alternative way !!So , now with all this new details in mind , I continue to give to it,my thump up.Because, at the end of the day , it will do what it promises .One last thing that impressed me , was that if you step at the center of the measured area , you can measure on an average rate about 15 meters in front of you ,And by turning your body 180 degrees another 15 meters at the back .So you can do safe measurements with out the assist of an second person ( tape meter) , Up to 30 meters .And with the same technique ( front + back) , even at the worst surface like the spayed plaster ( material cement ) , there is 14 meters of measured distance.I had one conversation on the job, about alternative “distance measuring systems” with laser pointers.Well, they do exist .But , how they will measure anything .... at out-door ... with a bright sun light ?The ultrasonic meter did not care about the sun light,and it offered reliable hand held measurements , with out tripod on daylight .Conclusion… If there is an silent battle, between ultrasonic VS laser,Both contesters haves their weak points.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: August 26, 2010, 07:28:34 pm
content: And the last part of this review ..Battery consumption ..The meter uses one 9 Volt battery .When it powered up , it uses 8mA as consumption .Its measurement lasts for 3 seconds ,And It draws as 19mA , and then falls back to 8mA .It has an auto power-off function ,And at this mode , my analog multimeter Goerz Metrawatt at the 2.5mA range was unable to detect any current at all !!So I conclude that by keeping the battery always connected ,There is no danger to find it empty, even at long periods of storage.