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.
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.
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
I have the strange feeling that they might actually (close to) be the same as the Extech SDL series.
Alghough the buttons are placed differently, the rest looks pretty similiar.
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)
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.