Acuity sells what I need brand new for $1000. Keyence appears to be a much more common brand, given by the number of eBay items. These are not time-of-flight devices; they work instead by measuring the position of an angled laser spot on the target.
I’m looking at the Keyence IA-065. The working range of 2.17" - 4.13” would work for my application. I’m a bit puzzled by the “linearity" spec on the data sheet. It reads as follows: +- 0.1% of F.S (F.S.=+-10 mm 0.39”, 55 to 75mm 2.17 to 2.95”) I read that as within the range of 55mm to 75mm, the linearity will be within 0.2% of that range, which comes to 0.04mm or about 0.0016”. Is my logic and math correct? Second question, what is the simplest (and cheapest!) way to get this analog voltage into LinuxCNC. I do have a couple of 24-bit I2C devices on hand (ADS1220). Is this workable without writing a driver or something like that? > On Mar 7, 2022, at 2:01 PM, gene heskett <[email protected]> wrote: > > On Monday, 7 March 2022 12:44:21 EST Thaddeus Waldner wrote: >> Hi, >> >> I’m looking for a laser distance sensor with about 1-3 thousandths >> resolution and about a 5-10” working range. I wouldn’t mind buying a >> used unit. > > 1. I didn't know they came in that high a resolution w/o needing a quorum > of the US Senate to authorize the payment, then signed by the President. > > If you want to know why, calculate the time difference of that 3 > thousandths of an inch increment, remembering that it has to travel out, > and back to the measuring device, equal to C/2 in speed. You will I > suspect will come up with a very small fraction of a picosecond. > > Interferometry can measure that change, but the mod function to detect > the individual null and count it has to start at zero, or a known micron > sized distance before it can count the nulls passing by as it moves from > zip distance, back to your point of interest at a 12" max range. Moving > slow enough to count, will take a 2048 bit counter and several days. > > Technically, we can do it but you'll need a couple of dump trucks full of > gold to finance one neasurement. We can't yet buy a calibrated answer in > 10 milliseconds for a $500 bill. Someday? Maybe, but it may take a new > method to be invented. > >> Does anyone here know of some brands/ models to check out? >> >> Google has pointed me at some Acuity products but I wondered if there >> were other options besides that. >> >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > Cheers, Gene Heskett. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
