OPT4001 light sensor

[glenenglish]

anyone here used the TI OPT4001 ambient light sensor ? experiences ?
https://www.ti.com/lit/ds/symlink/opt4001.pdf?
thanks
glen

[Phil1977]

It´s the easiest way to measure a wide range of illuminance, from below 1/1000 lx to around 100klux.

The internal logarithmic readout makes application much easier than with most analogue devices.

What do you need it for?

[SiliconWizard]

anyone here used the TI OPT4001 ambient light sensor ? experiences ?
https://www.ti.com/lit/ds/symlink/opt4001.pdf?
thanks
glen

I have used the -Q1 version, which happens to be slightly different, but very similar.
It works as advertised but has a few quirks. Do you have specific questions?

[glenenglish]

thank you both for the replies

IE, nothing complex, just wanted peoples thoughts- as the datasheet reads well and is a comprehensive device, and the price is OK. as usual there devil is in the detail.

There is a wide choice of devices out there, and this one looks the most flexible.

FWIW I'm using it for two purposes -

1) to guess the appropriate ambient light levels to drive a diisplay backlight (nothing special)
2) to use a detection of light level when someone needs to wake up the display from  ' backlight saving' brightness to full smoke.. (IE wave your hand in front of it - create a shadow , a change etc . There is enough luminosity frrom the display reflection from the hand to make that work, although I also have a led that can be lit up. )nothing special , either)

The fast readout rate (for coarse measurements) is useful for my change detection requirement.
-glen

[SiliconWizard]

I'll have a look back at the details to list what kind of quirks I found on this part.

The good is that it has a pretty wide dynamic range. Note that if used near a display with backlight, it will sense some of the light emitted by the display, which could make it a bit convoluted to efficiently use and distinguish ambient light from display light, unless you take proper measures to install it in an area that is decently isolated from the light emitted by the display itself. That's not specific to this sensor of course, but check its sensing pattern in the DS and make sure you place it in an appropriate location.

One of the quirks I remember of at least with the -Q1 is that it didn't seem to work properly when set in fixed-range mode and worked as expected in auto-range (which the DS recommends anyway although they don't quite say why other than to optimize the dynamic range, but you often don't need a wide dynamic when just used for backlight adjustment). In fixed range I would get weird measurements.

In my case, I was also looking for fast detection which made it look attractive, but keep in mind the above: when used for fast detection rates, the a fixed-range mode would be more appropriate (otherwise it'll keep changing its itnernal gain automatically), and again I couldn't make it work properly in fixed-range. Maybe you will be able to. I would suggest prototyping to make sure it works as you expect in your use case.

[glenenglish]

thanks
noted OK on the fixed range behaviour.
Yeah the datasheet shows the light  sensitivity angles for the DTS (SOT) package to be pretty wide- I would need to pot around it to limit what else it could see,
I really wanted a look-back-through the board type , like the OPT4001 in the Picostar package, but that single I2C address it supports is already used by another TI part  .. doh
I could use some sort of I2c expander to proxy the I2C address, but I dont care that much as to add ANOTHER line to the BoM for a I2C proxy...

I also liked the
https://www.vishay.com/en/product/80611/

but it doesnt seem to be available yet.