List: standalone runtime graph maker/ lux loggers (for flashlight reviewers)


My requirements were: (this thread turned in to a list with all kinds of lux loggers)

  • must be standalone (shouldn't have to be connected to PC or anything)
  • data should be transferred to PC easily... no strange or unreadable data
  • USB out for pc connection (preferrably)
  • able to set time intervals for recording (so the file doesnt end up with millions of data points when doing multi hour runtimes)
  • Exported file should be readible by non-dedicated software... think about a normal XLS file
  • Should use batteries... but DC power could be ok
  • batteries should last long enough for multiple runtimes.


I'd like to keep it extremely simple :) so they won't do it for me then :(

I wanted to use an old Smasung s3 mini, but it didn't work. No lightmeter. So I'll have to look for another one. Probably the best solution! In combo with the app!


I bought a new ZTE smartphone from Tracfone for $9.95 for this exact purpose

9.95? Are you kidding? Wow.

Yeah, they basically give them away in hopes you will use their service. I just checked, and there’s a newer upgraded ZTE for $14.95.

They aren’t bad phones if all you want to do is make phone calls, and txt message. In the US, all phones are required to be able to make emergency calls to 911 whether or not you subscribe to a cell service. So these cheap phones are good for emergency use as well

Not sure how good those meters below $50 will work, but here's what I've been using (about $180).

I've been using a Reed Instruments SD-1128SD (Amazon link) for all my runtime graphs. You can view my runtime graphs by clicking on my J5 or SC700d reviews in my signature. It meets all your requirements (except price) - although it has an RS232 connector for hooking up to a computer and would require a USB/RS232 adapter (I've never used or needed that function). Runtime data is copied to an SD card that you simply pull out and plug into your computer for the basic Excel file. Uses six AA batteries, which I've found gives about 3-4 days of runtime on Eneloops, but I also use the optional wall adapter for long tests.

If you order one of those Aliexpress meters, I would like to know how well they work.

Extech sells a similar meter here:

This might be a good option, except for the price ;) But I might just get it... the smartphone is hopeless.

Tonight another problem. After waiting 3 hours, I noticed the Ceilingbounce app already stopped after 2 hours :(
My phone probably just turned the app off or something, but this is annoying. I need to log longer runtimes as well.

I will look at some EU sellers

I have had the same issue with the Android app I use, but it’s just a quick trip over to the Doze settings (or your OEM equivalent) to make sure it doesn’t happen.
App info > Battery > Battery optimisation on stock Android Q.

Anybody any other option? Terry's option looks interesting, but something a little cheaper or at least available in the EU would be nice.

Finally I got myself a second hand Samsung J5... (from my sister) and it doesn't have a light sensor.. fail.

Finally got myself a second hand Extech HD450 for my runtime graphs. It's not perfect at all, but it will do the job..... I hope..

We'll see how cumbersome this is. It uses a USB Mini (not micro) to connect to a PC. You can either use it as a standalone meter, or connected the the PC. I tried it, connected to the PC, and it seems to be doing the job.... except for the data output.. it adds timestaps like: 2019-09-25 22:10:05. so need to figure out how to make that into clear data... starting from 0 minutes. Instead of the hours of the day.

How about the UI/UX? ughhhh the buttons you have to push and the settings you have to set.. just don't make sense at all.... so completely useless. I prefered having a few extra buttons just to manage these things. A clear Start recording and Stop recording would have helped as well. Can't understand these companies make so horrible UIs.

M. one can also use smartphone as luxmeter logger. there are apps on playstore. they save the data in a common format (csv or similar) and one can postprocess it on the PC or laptop.

Converting a time stamp hh:mm:ss to a counter starting from 0sec is a common task ,

Yes, I thought about a smartphone as well, but had no luck with 2. Both didn't have a light meter. Plus I wanted to be sure to have long batterylife.

smartphones have brightness sensors. the light meter is an android app. there are plenty of them called 'light meter' or 'lux meter' on google playstore.

smartphone won't die if it's connected to USB charging (powerbank or wall charger).

I've tried it, works well, convenient "UI" and file management. but sure, a physical light meter is the more robust alternative.

Sorry, I meant a light sensor. I also used the Light Meter app with my phone, but needed it to receive calls and messages. A second phone would be as expensive as a second hand /new lux data logger, but with extended battery life.

I could never figure that out either. So . . . . .

In my Reed Instruments, I always zero the hours/minutes/seconds just before I start a runtime graph. I have to do this every time I do a runtime, but it only takes seconds once you figure it out. Excel then accepts this as starting at 12:00am.

The Benetech GM1020 is ok if you master installing the driver (the device apparently uses a fake FTDI chip and needs an old driver) and upload the settings (doing this the first time is tricky). Beware: Windows 10 eliminates your driver in more recent versions, so it has to be reinstalled from time to time. And it’s getting harder each time.

Last time I did this I had to deinstall the Win driver and install the old driver before Windows could find the new, non-working one. Disconnecting from the net might work, too.

I can help if anyone wants to take this route. The GM1020 is the only budget meter able to store that many data points.

Good call Terry, that is a great idea. This is one of the things they could have improved, but on the other hand, most people probably use it for something else, and not for runtime graphs :)

I could find a driver and software online for the Extech, so I think I'm okay.. not sure if something could cause troubles in the future of course.

Thanks Unheard, thanks for sharing. If anybody goes that route, they know what to do.

I wonder if any of these companies would consider doing a group buy for a luxmeter that could log to USB.

I like the idea !

Note that the Reed Instruments does NOT have to be tethered to a computer. It has a memory card slot - that I remove when done with runtime tests. It also has an optional external power supply that can keep the data logging going for days if necessary (see sample below). I don't think the Extech has either. I wonder how long the Extech can run on one 9V battery? The Reed Instruments uses six AA's.

Just letting you know the pros and cons.

Although I already have 2 log meters, 1 being less than ideal and including some problems (Extech HD400) the SDL400 does a good job at what I want it to do.

But for the sake of other reviewers, a little bump to see if there are any other alternatives.

This looks like an upgraded GM1020?

Benetech GM1030