Simple way to measure the runtimes (TASI TA636B lux meter)

LED Flashlights – General Info
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Quest: to be able to measure/check the runtimes with the minimum effort, with the dedicated cheap lux meter without the need to keep the mobile phone/computer hooked to the task.

Solution: TASI TA636B Digital Light Meter

  • Bluetooth connection and Android/iOS apps
  • internal memory for up to 2,000 samples; time between the samples can be set in 1..60 seconds range
  • ability to trigger the measurement via the app and let it run on its own
  • the results can be downloaded to the app, viewed in the app and exported to PDF and Excel formats

I don’t need an absolute accuracy when all that I want is to recognize if the output is regulated, if/what stepdowns are present, or the total runtime. Thanks to internal memory it does not need mobile/computer during the measuring run.

This ~recently premiered meter meets my needs perfectly.

The results show here are for Wurkkos HD03, for the Flood channel on the High level.

initially posted on Reddit: https://www.reddit.com/r/flashlight/comments/1pwy1uv/simple_way_to_measure_the_runtimes/

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Exactly what I need, thank you for posting!

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Looks good. There’s also an app for android called “light meter” that uses the light sensor on your phone, it creates very similar graphs of relative output

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The key point is to not have to dedicate your mobile for several hours to carry out the runtime test. If you have a spare mobile then sure, it will probably be as good (and cheaper).

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Ordered, Thanks!

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Thanks for the great info!

Do you know the lowest output, in lumens, this tool can measure?

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As per the specs:

Range

  • 0.1 ~ 200,000Lux / 0.01 ~ 20,000Fc

Accuracy

  • ± (4%+10dgts); calibrated under the standard incandescent lamp at color temperature 2856K;

Repeatability

  • ±2%

Measuring Level

  • 200 / 2,000 / 20,000 / 200,000Lux; 20 / 200 / 2,000 / 20,000Fc

Resolution

  • Lux<200: 0.1; Lux≥200: 1 / Fc<20: 0.01; 20≤Fc<200: 0.1; Fc≥200: 1
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thank you..

Maybe as low as Level 6 on a Zebralight SC54c N, which is specified to run at 7.1 lumens for 55 hours

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I don’t believe this very meter is sensitive enough to measure firefly levels. You would also need really small integrating sphere to limit the losses on the reflections. But even that would only let a fraction of the emitted light to get registered by the emitter.

Clarification: directing the flashlight at the meter would not give the total lumen flux.

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Oh yeah you did say that in the OP sorry :rofl:
Looks good!

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  1. VERY NICE. Thanks for sharing. Is this the item, from “Ideal Concept Store”:
    https://www.aliexpress.us/item/3256808746187479.html?search_direct=true&spm=a2g0o.productlist.0.0&gatewayAdapt=glo2usa4itemAdapt

  2. Got TASI for my iphone through iOS app store, but couldn’t find TASI app on Google Play for my android phone (I tend to be technically challenged). How do I get the app for Android pls?

  3. Could the graph be set to percentage, of starting brightness?

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agree, it would just show changes in output over time.. which could still be useful.. even if it does not report actual lumens

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  1. That’s the one
  2. I’m using iPhone so the link led me to the AppStore. In case of Anduril you will have to download the .apk file and install it „locally” (I did not try that). Check the download page: http://china-tasi.com/appDown
  3. The app gives the absolute values (observe the top part of the first OP picture). You would have to export the data to Excel (see the right-most screen shot on the third OP picture) and recalculate the values, assuming the first sample as your 100% „reference”. This way you will be able to create the graph as the bottom one on the first OP picture
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Good point. If you are not at risk of over-saturating the sensor (indeed not a problem for the lowest modes), then you can point the flashlight directly at the sensor.

I’ve just checked and the lowest mode of SC65c HI gives ~40.0 lux (~1cm distance) so plenty of range/resolution to capture the changes.

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thank you!
the default lowest mode is claimed to be 0.11 lm and is claimed to last 3.7 months..

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That actually would not be even remotely possible:

2000 samples * 60 seconds = ~33.3 hours runtime.

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it might make more sense to just take a Lux reading once every 10 days, with the light touching the sensor, for distance consistency.. LOL

I dont expect to see much change in Lux.. it would just be a way to confirm if the total claimed runtime is true.. with just 11 readings. (3.7 months is 111 days).. I wont have the patience to test that :wink:

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Such periodical, manually triggered measurements can be also done with any lux meter including those in the form of the mobile apps.

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Who makes it? A search for “light meter” show’s several options but I don’t see one that produces nice plots

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Check my earlier reply: