Light Sensor Overwhelmed

[lutefisky]

Raspberry Pi 3, latest Raspian Jessie. So I have a project that’s using a TSL2561 light sensor and when the sun is shining directly at it the sensor is overwhelmed and it reports an eronious number (364). Looking into the data sheets on this device shows that it has a gain adjustment and the ability to reduce the frequency of readings which would help in this particular situation. However, as I’m running it through Cayenne I don’t believe I can adjust those parameters.

My other option is to give the sensor some sunglasses and reduce the amount of light going in. I’d prefer to get as accurate a reading as possible, but if that’s all I can do at this time then so be it. Anyone else bump into this before?

[adam]

Unfortunately you’re correct that we don’t have direct access to change the reading frequency. There’s a similar post here: Scheduling Feature - Random on/off Cycles & Dusk/Dawn - #6 by bestes Look’s like he is going the sunglasses route.

@kent_chalmers

yes its pretty handy, one thing that caught me out was that the TSL2561 will overload in full sun. It is VERY sensitive. I have found its only great for indoors. It has a range from 0 - 40,000. But full sun can be up to 120,000. So keep it indoors or under a filter of some kind (smoked glass or plexi/acrylic) and watch the graph over a day or two and you can then work out your baselines.

When it overloads it gives a “NAN” value or basically can’t post any data. so don’t panic if you find this (I thought I had a broken sensor).

[Ian]

I almost hate to say it, but with the Arduino integration, that code flexible route is now an option.

One thing I find odd is in my installation of a TSL2561 I’m not seeing anything close to max readings.

Ian

[lutefisky]

Thank you for the answers. it is.