Schematic for an IR proximity switch

Thread Starter

spike1947

Joined Feb 4, 2016
266
Hi
I want to make a schematic for a 24v ir proximity switch to switch a relay on when beam is blocked ! .
Any info will be highly appreciated to be able to do that .
cheers
Spike
 

Thread Starter

spike1947

Joined Feb 4, 2016
266
If you use a typical modulated beam pair TX/RX pair, the signal will change when the beam is blocked. For example, with this Vishay device (https://www.vishay.com/docs/82669/tsop32s40f.pdf ), when the beam is blocked, the signal goes low.

Are you sure you want to use a blocked-beam principle instead of reflected beam?
Hi
Thanks for your reply, yes want to use "blocked beam " have the diode emitter and photo diode collector.
cheers
Spike
 

jpanhalt

Joined Jan 18, 2008
10,913
If that is what you intend to use, do you need a schematic for both the IRED emitter and detector? Please provide part numbers or links to the data sheets for the ones you intend to use.
 

Thread Starter

spike1947

Joined Feb 4, 2016
266
If that is what you intend to use, do you need a schematic for both the IRED emitter and detector? Please provide part numbers or links to the data sheets for the ones you intend to use.
Hi
Thanks for your reply , I am really wanting a schematic to make a new board to incorporate a ic in the circuit, I need to operate a 24v relay !.
cheers
Spike
 

MisterBill2

Joined Jan 23, 2018
7,687
You do not need an IC to drive a relay from a blocked-beam photosensor, just use an MPSA13 transistor and a phototransistor to detect the beam.
AND, that arrangement is NOT a proximity switch, it is a photosensor switch.
 

Thread Starter

spike1947

Joined Feb 4, 2016
266
You do not need an IC to drive a relay from a blocked-beam photosensor, just use an MPSA13 transistor and a phototransistor to detect the beam.
AND, that arrangement is NOT a proximity switch, it is a photosensor switch.
Hi
Thanks for your reply, ok , would you have a schematic of a circuit incorporating that transistor using 24v as the output to the relay ! .

cheers
Spike
 

Thread Starter

spike1947

Joined Feb 4, 2016
266
Hi Spike,
you can use this circuit with the reflection type , 2nd diagram,,you can use the relay as the 1K load R3 instead and omit the IC ., There's a video at the end.

https://learnabout-electronics.org/Semiconductors/opto_54.php
Hi again
Sorry if I seem to be going on a bit with this project of mine , am attaching a schematic of what I would like to make, the difference being that I don't want to use a " Slotted Optical Switch" I need the ir led emitter and the ir photodiode collector to be placed about 10mm apart to enable a object to be able to travel through the beam thereby energizing the relay ie: there is a 8mm x 200mm slot and each ir is placed each side of the slot !facing each other .
Spike
 

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Tonyr1084

Joined Sep 24, 2015
5,491
You're talking about a 7 7/8 inch gap. You're not going to find a ready made sensor that big. You'll have to either build a trap (calling it a trap because it senses when something breaks the beam) build a trap that big OR you can set up a transmitter (IR laser) and receiver (IR sensor) side by side and have the beam point to a mirror on the opposite side of the trap zone. The laser beam bounces off the mirror back to the sensor. When the beam is broken you get your alarm.

Look on YouTube for laser beam security and you'll probably find something that might help you figure this out. In fact, here's one quick video:
 

Thread Starter

spike1947

Joined Feb 4, 2016
266
You're talking about a 7 7/8 inch gap. You're not going to find a ready made sensor that big. You'll have to either build a trap (calling it a trap because it senses when something breaks the beam) build a trap that big OR you can set up a transmitter (IR laser) and receiver (IR sensor) side by side and have the beam point to a mirror on the opposite side of the trap zone. The laser beam bounces off the mirror back to the sensor. When the beam is broken you get your alarm.

Look on YouTube for laser beam security and you'll probably find something that might help you figure this out. In fact, here's one quick video:
Hi
Thanks for your reply, the gap is only 20mm (3/4") .
cheers
Spike
 

Tonyr1084

Joined Sep 24, 2015
5,491
Sorry. Somehow I got to thinking you were talking about 200mm. My bad.

20 ÷ 25.4 = 0.787 inches. Little more than 3/4 inches. Even still, I don't know of anyone who manufactures a sensor that big. Not saying they don't - just saying I don't know of one.
 

Thread Starter

spike1947

Joined Feb 4, 2016
266
Sorry. Somehow I got to thinking you were talking about 200mm. My bad.

20 ÷ 25.4 = 0.787 inches. Little more than 3/4 inches. Even still, I don't know of anyone who manufactures a sensor that big. Not saying they don't - just saying I don't know of one.
I don't need a sensor that big, that is the gap between the ir diode and the ir photodiode , they will be facing each other across the gap, when something falls through the gap and breaks the signal it will trigger a relay ! .
Spike
 
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