OPT3001-Q1: LUX value keep changing

James Zhan

Expert 4365 points

Part Number: OPT3001-Q1
Other Parts Discussed in Thread: OPT3001

Hi team,

My customer is using OPT3001-Q1 and found the lux value changing from time to time.

And if we have someone stand 50cm in front of OPT3001-Q1, the lux value is also changing.

Does this have something to do with the IR rejection?

Could you help to check if you have any advice?

Thanks.

17:53:38:192[I:febecadc|ILL]##### read ambient lux:35

17:53:40:197[I:febecadc|ILL]##### read ambient lux:32

17:53:42:203[I:febecadc|ILL]##### read ambient lux:30

17:53:44:206[I:febecadc|ILL]##### read ambient lux:32

17:53:46:208[I:febecadc|ILL]##### read ambient lux:31

17:53:48:210[I:febecadc|ILL]##### read ambient lux:31

17:53:50:203[I:febecadc|ILL]##### read ambient lux:31

17:53:52:224[I:febecadc|ILL]##### read ambient lux:29

17:53:54:226[I:febecadc|ILL]##### read ambient lux:28

17:53:56:215[I:febecadc|ILL]##### read ambient lux:27

17:53:58:229[I:febecadc|ILL]##### read ambient lux:28

17:54:00:236[I:febecadc|ILL]##### read ambient lux:28

17:54:02:242[I:febecadc|ILL]##### read ambient lux:29

17:54:04:244[I:febecadc|ILL]##### read ambient lux:29

17:54:06:253[I:febecadc|ILL]##### read ambient lux:28

17:54:08:240[I:febecadc|ILL]##### read ambient lux:30

over 4 years ago

0 Alex Bhandari-Young over 4 years ago

TI__Mastermind 25895 points

Hi James,

I am checking into this.

Best,

Alex

0 James Zhan over 4 years ago in reply to Alex Bhandari-Young

TI__Expert 4365 points

Hi Alex,

Thanks for the attention.

Please let us know if you have any advice, thanks.

0 Alex Bhandari-Young over 4 years ago in reply to James Zhan

TI__Mastermind 25895 points

Hi James,

I see you have lux level changing between 27 and 35 lux so ambient light is quite low. If a person is standing in front and blocking some light then slight movement can affect the light sensor reading. Depending on conditions light sensors can be quite sensitive to changes in light level.

Best,
Alex

0 Zhu Chaochao over 4 years ago

Prodigy 50 points

This one is static and does not face people, but sometimes the deviation of the obtained light value is too large, most of the time it is the same, it is normal

This is left to stand, and no human being, but sometimes get to light the value of the deviation is too large, most of the time is constant, it is normal

0 Alex Bhandari-Young over 4 years ago in reply to Zhu Chaochao

TI__Mastermind 25895 points

Hi Zhu,

This is not expected from sensor side. If light level is constant then the sensor is expected to be constant. How are you ensuring the light level in the test setup is constant?

Best,

Alex

0 Zhu Chaochao over 4 years ago in reply to Alex Bhandari-Young

Prodigy 50 points

I have two main requirements. 1. The deviation value sometimes fluctuates greatly when standing still, which is abnormal in my opinion. Because the surrounding environment is basically unchanged. 2. We don't need infrared sensor, can we filter out infrared sensor?

0 Zhu Chaochao over 4 years ago in reply to Alex Bhandari-Young

Prodigy 50 points

0 Alex Bhandari-Young over 4 years ago in reply to Zhu Chaochao

TI__Mastermind 25895 points

Hi Zhu,

OPT3001 filters out IR light. You recorded at change from 35 lux to 27 lux. What is the light source in this case?

Best,

Alex

0 Zhu Chaochao over 4 years ago in reply to Alex Bhandari-Young

Prodigy 50 points

Light with natural light from Windows, there are light and infrared light of the body

0 Alex Bhandari-Young over 4 years ago in reply to Zhu Chaochao

TI__Mastermind 25895 points

Hi Zhu,

I did a test with our EVM and you can see the result here under a lamp. The variation is less than 1 lux with a light level of 500lux so less than 0.2%. If you are doing test in a room with sunlight and other light present it seems there may be some varying light levels in your setup as these are not controlled light sources.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/1023/2021_2D00_05_2D00_06-11_2D00_39_2D00_50.mkv

Best,

Alex

0 Zhu Chaochao over 4 years ago in reply to Alex Bhandari-Young

Prodigy 50 points

How should I handle these controllable source?The impact of these light sources in about 1-7 lux.

0 Alex Bhandari-Young over 4 years ago in reply to Zhu Chaochao

TI__Mastermind 25895 points

Hi Zhu,

It may help to have a reference meter to check against. I would also advise to do test in a dark room with only a single light source that is allowed to stabalize. Even a regular incandescent lamp can give a stable output once warmed up. It will have the AC mains voltage switching, but this will not show up on our sensor.

Best,

Alex

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OPT3001-Q1: LUX value keep changing