I have a fully functioning proof of concept with a Raspberry Pi Zero W and my TSL2591 sensor. The code is a bit sloppy still, but it works.

Pros:

• Output is fairly clean, no excess noise
• Sensor quality is known unlike using an old Android phone (the one I'm using has a pretty low measurement resolution)
• Includes an IR sensor, though I haven't added code to measure that yet
• Extremely configurable
• Cheap! The Pi Zero W and the sensor are less than $20. I've added some indicating LEDs to my build, and you'll need some wire, a microSD card, and probably a microHDMI adapter for initial setup

Cons:

• Some assembly and soldering is required
• To use this standalone you'll need a basic understanding of ssh and scp tools. If you're using Linux or OS X, it's very easy

If anyone is interested, contact me and I can send a copy of my script to test. If it works I may make it available somewhere in the future.

Interesting, does it work as a stand alone product?

I still have a raspberry doing nothing for over 1,5 year

I have been thinking of building the same, but using ESP32 insted of the Pi. Oled screen for quick readouts, web ui with configuration and graphs, logging to the real database are on the planed features list.
I take it you did it in Python? I’d be interested in taking a look.

That’s similar to what I use… an ESP8266 hooked up to a TLS2591

Cross post from the “What did you mod today?” thread from last February:

gchart wrote:

A year or so ago I built a lumen tube using a Wemos D1 Mini (ESP8266) running Arduino and a TSL2591 breakout board. Super small, USB powered, and feeds out results over WiFi via a built-in webserver. It makes runtime/output charts really easy.

Yokiamy wrote:

Interesting, does it work as a stand alone product?

I still have a raspberry doing nothing for over 1,5 year

Sort of. You could easily configure it to start on a button press, but I just start mine with an ssh command.

One thing i found out is that they look cheap but they are not cheap

$210?!

Terry Oregon wrote:

Quote:

so need to figure out how to make that into clear data… starting from 0 minutes. Instead of the hours of the day

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.

I had the same problem with Excel.
I ended up adding a column starting at 0, and progressing at the sample interval. Using that as a time scale.
I like Libra Calc for the graphs, but could never get the darn thing to put a time scale on the graph correctly. It seemed to have a mind of it’s own as far as making the time interval on the axis.
But other than that, it worked well and is free.

I have been using one of the osram diodes that seem to be inside all of the reasonable cost lux meters.
In one of the circuits from Terry’s vast diode test. They are quite cheap.
I measure with PICO-Log software. But that’s not a stand alone option.
All the Best,
Jeff

jeff51 wrote:

Terry Oregon wrote:

Quote:

so need to figure out how to make that into clear data… starting from 0 minutes. Instead of the hours of the day

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.

I had the same problem with Excel.
I ended up adding a column starting at 0, and progressing at the sample interval. Using that as a time scale.
I like Libra Calc for the graphs, but could never get the darn thing to put a time scale on the graph correctly. It seemed to have a mind of it’s own as far as making the time interval on the axis.
But other than that, it worked well and is free.

I have been using one of the osram diodes that seem to be inside all of the reasonable cost lux meters.
In one of the circuits from Terry’s vast diode test. They are quite cheap.
I measure with PICO-Log software. But that’s not a stand alone option.
All the Best,
Jeff

Python is your friend.

bmengineer wrote:

Python is your friend.

Ha!, I’m too old, Python is your friend,
Fortran 4 was my friend…

Brute force in Excel. Never make an elegant formula, when 5 columns worth of obscure calcs will do….
All the Best,
Jeff

ChibiM wrote:

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

https://aliexpress.com/item/33010626789.html

Chibim

This looks like a very interesting meter, it can record 2000 data points with a selectable interval, and its cheap, so it might be useful.
It has bluetooth and usb (for retrieving only probably)

Please find the manual Here

I’ve added a short post with a bit of information about what I ended up doing. It works great for me, and I’ll keep working on it to clean it up if there’s interest.

bmengineer wrote:

I’ve added a short post with a bit of information about what I ended up doing. It works great for me, and I’ll keep working on it to clean it up if there’s interest.

Very interesting!
I still have a raspberry pi catching dust on the shelf…

ChibiM wrote:

bmengineer wrote:

I’ve added a short post with a bit of information about what I ended up doing. It works great for me, and I’ll keep working on it to clean it up if there’s interest.

Nice! 

If there is a nice read up on how to set it all up, that would be great!

 

No write up yet, it’s still pretty alpha. But if you can figure out how to get a Pi up and running you can work this out too!

I’ve been meaning to post the details on my lumen tube build for some time, finally got a first-pass done.

https://github.com/gchart/luxmeter

gchart wrote:

I’ve been meaning to post the details on my lumen tube build for some time, finally got a first-pass done.

https://github.com/gchart/luxmeter

!{width:600px;max-width:100%}https://github.com/gchart/luxmeter/raw/main/lux_meter_sensors.jpg!

Thanks bmengineer! It’s pretty basic but it’s great having immediate visual feedback. It also displays the IP address at start up (despite using a reserved IP) and diagnostics in case any sensors aren’t detected.

I just pushed a big update to my Lux Logger project.

Same hardware:

• an ESP8266
• a small OLED screen
• TSL2591 lux sensor
• MLX90614 IR-based temperature sensor

Instead of using an app or a batch script to log the readings, the ESP8266 itself is hosting a webpage that you pull up. That way you can use your phone, a tablet, or a computer to perform tests. And instead of polling data at set intervals, this keeps an open socket connection that quickly pushes new data any time there’s a sufficient change in the data. Oh, and I added a real-time graph.

Fascinating stuff! You Rock Gchart!

Strange that there aren’t more manufacturers which incorporate this, and still work with relative ancient technology which are way overpriced
I actually built your specific project and it works amazing !
And the best part of it is that the parts are dirt cheap! (ok, it lacks a nice housing etc, but even that can be arranged for a few dollars more)

Some pics of my result here

Awesome! Glad you got it up and going. It’s one thing for me to put one together (as I debug and such). It’s entirely better to see someone else successfully replicate it.

This is a great post, so I’m dredging it up to see if there are any new logging light meters (or better apps) out there.

I find myself getting closer to choosing the light I will use in certain scenarios and want to be able to do long tests (instead of using the lights for a long time and guessing which is better).

I haven’t heard of anything else new lately, but if you run across anything, please share! Or if you decide to put something together based on my project, let me know if you have any questions.