Infrared (IR) break-beam sensors

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tmillward
 
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Infrared (IR) break-beam sensors

Post by tmillward »

hi

ref 5mm IR Break Beam Sensor

does the the IR beam have to be fully broken, ie 5 mm or greater
can IR beam be partially broken,ie object 2 mm to trigger on 5 mm IR receiver?

regards

Tim

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adafruit_support_bill
 
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Re: Infrared (IR) break-beam sensors

Post by adafruit_support_bill »

The receiver detects a decrease in the intensity of the IR beam. The exact threshold for triggering a beam break will depend on the distance between transmitter and receiver and how precisely they are aligned.

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tmillward
 
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Re: Infrared (IR) break-beam sensors

Post by tmillward »

what i mean is the beam is 5 mm in width but i want to trigger it with a 2 mm width object, i understand the intensity and distance aspect.
ie break the beam partially!.is this possible ?

regards

Tim

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adafruit_support_bill
 
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Re: Infrared (IR) break-beam sensors

Post by adafruit_support_bill »

If you cover part of the beam, the intensity at the receiver is reduced. It is also reduced if you move the transmitter further away or don't have them precisely aligned. So, as I said, the exact threshold for triggering a beam break will depend on the distance between transmitter and receiver and how precisely they are aligned.

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tmillward
 
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Re: Infrared (IR) break-beam sensors

Post by tmillward »

I get your point know!

how do you measure intensity of https://www.adafruit.com/products/2168

its not volts , frequency; but what frequency
datasheet in chinese?

regards

Tim

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adafruit_support_bill
 
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Re: Infrared (IR) break-beam sensors

Post by adafruit_support_bill »

The receiver doesn't let you measure intensity directly. The output of the photo-transistor is used to trigger another transistor with an open-collector output. When the photo-transistor falls below the 'beam break' threshold, the output transistor turns on and pulls the output low.

Wired as shown in the tutorial, you will get a digital LOW when the beam is broken and a digital HIGH when it is not.
https://learn.adafruit.com/ir-breakbeam ... s/overview

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mgonzalez71
 
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Re: Infrared (IR) break-beam sensors

Post by mgonzalez71 »

Good morning,

I purchased both the IR break-beam sensor (5 mm) and the FSR-406.

All the tutorials and source code I have found have been based on/used Arduino software. I am not using either, I have Nordic Semiconductor board nRF52832 ( https://www.nordicsemi.com/eng/Products ... y/nRF52-DK ) and using Keil micro-vision. My question is if there is any source code using anything else?

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adafruit_support_bill
 
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Re: Infrared (IR) break-beam sensors

Post by adafruit_support_bill »

We do not have any source code for other platforms, but both of these are fairly simple sensors, so porting should not be difficult.

In the case of the break-beam, it is a simple digital HIGH/LOW output.
For the FSR, you just need to substitute your ADC raw range and analog reference voltage in the scaling computation.

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mgonzalez71
 
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Re: Infrared (IR) break-beam sensors

Post by mgonzalez71 »

Awesome! Okay, thank you for the quick reply.

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