Arduino Forum

Using Arduino => Sensors => Topic started by: BLakatos on Aug 29, 2019, 02:43 pm

Title: How can I tell how the max frequency an IR Sensor will detect at?
Post by: BLakatos on Aug 29, 2019, 02:43 pm
I have this sensor

https://www.amazon.co.uk/gp/product/B07PY3CVSV


I want to use it to detect changes between white and black stripes.  I'm hoping the sensor can detect changes in the stripes as they fly by at a rate of one stripe per 1-2ms.

I can't find the rate at which this sensor updates though? 

Im very new to arduino so I might not be searching for the correct terms.  I've been looking at the data sheet, and googling for frequency/refresh rate/speed/etc to no avail.

If IR sensors can't pick up changes that quickly is there another type of sensor I should be using?

Thank you!
Title: Re: How can I tell how the max frequency an IR Sensor will detect at?
Post by: pylon on Aug 29, 2019, 04:31 pm
IR sensors theoretically are able to detect signals that fast. As that supplier is not providing a schematics for it's product you have to try it out if it works. It's even not clear if the emitted IR light is modulated on an 38KHz carrier as it's often done to avoid false alarms by ambient light.
Title: Re: How can I tell how the max frequency an IR Sensor will detect at?
Post by: BLakatos on Aug 29, 2019, 04:50 pm
Thank you for the info!

Would you advise I get a different IR sensor?

I am planning on using it outside.  The setup will be with the sensor just a couple mm from the white/black stripes.  I'm also going to look into a light shield of some sort to try to help normalise the outdoor conditions.
Title: Re: How can I tell how the max frequency an IR Sensor will detect at?
Post by: Paul_KD7HB on Aug 29, 2019, 06:16 pm
I have this sensor

https://www.amazon.co.uk/gp/product/B07PY3CVSV


I want to use it to detect changes between white and black stripes.  I'm hoping the sensor can detect changes in the stripes as they fly by at a rate of one stripe per 1-2ms.

I can't find the rate at which this sensor updates though? 

Im very new to arduino so I might not be searching for the correct terms.  I've been looking at the data sheet, and googling for frequency/refresh rate/speed/etc to no avail.

If IR sensors can't pick up changes that quickly is there another type of sensor I should be using?

Thank you!
You are going to have to get the device and test it. You did not tell us what the black and white stripes are on and how you will be able to tell white or black from the background, all in IR light. For all you know, all three will appear black in IR light.

Paul
Title: Re: How can I tell how the max frequency an IR Sensor will detect at?
Post by: MarkT on Aug 31, 2019, 11:20 pm
Without a decent datasheet to answer the question the only way is to measure it or ask the manufacturer.
Title: Re: How can I tell how the max frequency an IR Sensor will detect at?
Post by: dougp on Sep 01, 2019, 06:49 am
The Amazon blurb includes this text: tube infrared emit a certain frequency,

This hints at a modulated signal.  Maybe try blocking the emitter and send a beam from your TV remote?
Title: Re: How can I tell how the max frequency an IR Sensor will detect at?
Post by: Wawa on Sep 05, 2019, 07:26 am
The module linked to in post#0 is analogue IR, with an adjustable threshold detector (digital out).
The 100 ohm resistor (bottom/right, 101) provides the ~37mA DC LED current.
No modulation at all.
Therefore it has a short range, and is sensitive to ambient light.
Should not be a problem for a line follower though.
Leo..