Recommendation need: Lux meter - Page 1
Forum section: electronics / general

author: con-f-use
author_rank: Unknown
timestamp: August 05, 2014, 10:49:47 am
content: I'm looking for a good lux meter (luminometer) to test led lighting. Price should be about € 30,-. I will not use it that often, it just needs to be in the ball park. Can you recommend a good unit?

author: Kjelt
author_rank: Super Contributor
timestamp: August 05, 2014, 11:01:20 am
content: Probably need to look in the chinese market but if they are any good?Starting prices in europe are around €40.- for the Voltcraft luxmeters.

author: saturation
author_rank: Super Contributor
timestamp: August 05, 2014, 09:36:12 pm
content: If your needs are non-professional, many 'Mastech' style luxmeters cost less than $15.Expensive meters are very explicit about the wavelength sensitivity, the evenness by which light is passed into the sensor and any optics it uses. The Minolta is a highly regarded reference meter.http://store.imatest.com/minolta-cl-200a-chroma-meter.htmlhttp://www.otc.co.uk/Problem_With_Lux_Meters.phpThe sensor assembly and optics are the single most costly item. Black line = ideal, green = best meter, yellow = better, red? blue? lines other meters.So a problem with basic luxmeters is that the lux it measures may not conform to the standard curve; if you have a spectra curve at least you know what the meter's biases are. A luxmeter alone doesn't show the dominant color of the light source, particularly LED. It may not be possible to compare the reading of one luxmeter to another without knowing each spectral curve, so anything but a chroma meter has limited value.The general use folks have is the brightness of A vs A' when A' is A under various power levels or lens setup, but when doing A vs B source comparisons, you need to be sure about the spectra of A vs B to be a valid comparison.

author: mrflibble
author_rank: Super Contributor
timestamp: August 06, 2014, 05:32:02 pm
content: Quote from: saturation on August 05, 2014, 09:36:12 pmAgreed. Those are acceptable for hobby purposes. The absolute measurement on these things is in the category of"meh", but relative measurements are quite useful. So for comparisons of led lighting A vs led lighting B it does the job.

author: saturation
author_rank: Super Contributor
timestamp: August 07, 2014, 01:59:38 pm
content: There are apps on Android or iPhone for luxmeters. Caveat emptor, and many are free. If you can calibrate the app against a good luxmeter then you are set. The phone luxmeter uses the CCD camera as a light sensor; so its not the specific sensor dedicated devices use that emulate the human eye but the app could 'compensate' in software and adjust for those deviations, so its worth a look.If you use Android and you get to test it, let us know here so I can check it out too.

author: mrflibble
author_rank: Super Contributor
timestamp: August 07, 2014, 02:25:59 pm
content: Quote from: saturation on August 07, 2014, 01:59:38 pmNice re-use of already present goodies. Any idea what the dynamic range of that solution is like?

author: saturation
author_rank: Super Contributor
timestamp: August 07, 2014, 03:47:33 pm
content: ... am just looking at Android's offering and will give it a try. If you have time too why not check it out and report back. I do have a cheapo "1HL" luxmeter that I calibrated against a Chroma Meter so the comparison may have some validity.Quote from: mrflibble on August 07, 2014, 02:25:59 pm

author: saturation
author_rank: Super Contributor
timestamp: February 09, 2015, 09:24:42 pm
content: I got to compare 3 Android luxmeter apps against a 1HL luxmeter calibrated between 1-2000 lux.The linearity and precision are similar to the reference device, and resolve about 1 lux. Android versions are off 25-50% versus the 1HL luxmeter. Android devices read 25-50% off against another Android device running the same app. However, different luxmeter apps run on the same device read identically. So in toto, these app luxmeters work but must be calibrated.https://play.google.com/store/search?q=luxmeter

author: vikasbly44
author_rank: Contributor
timestamp: February 10, 2015, 07:58:47 am
content: Amprobe LM-200 LED Light is the good led lux meter.