Digital IR sensor

[Varunme]

Anybody have a schematic for digital IR sensor ?

 

[Sceadwian]

Define digital IR sensors.. Those are very open ended words.

 

[koolguy]

Here it is....

 

[Varunme]

Define digital IR sensors.. Those are very open ended words.

sensor that can turn off and on a digital input of microcontroller and not the analog input

 

[Sceadwian]

Quite often what's used is an actual dedicate IR receiver, they often contain block diagrams which might help you work out a schematic for one of your own. They're very simply, generally an amplifier with a few filter stages.

 

[Varunme]

Quite often what's used is an actual dedicate IR receiver, they often contain block diagrams which might help you work out a schematic for one of your own. They're very simply, generally an amplifier with a few filter stages.

we can get digital signals from it ?
can u name one ?
using opamp, is it reliable ?

 

[Electroenthusiast]

You need to use a IR LED, which is pulsated using a 555 timer. And at the other end you need to use a TSOP17XX circuit.

 

[Varunme]

IR led and a TSOP17XX to interface with uC ?

 

[ericgibbs]

IR led and a TSOP17XX to interface with uC ?

hi,
This link is a IR pulse generator that will suit a TSOP1738

https://www.electro-tech-online.com/blogs/ericgibbs/196-tsop1738-when-used-beam-break-detector.html

Added the TSOP circuit.

 

[Gobbledok]

You can get a much better, adjustable range if you use a (more expensive) Sharp IR sensor connected to the comparator input of your microcontroller, with the internal, adjustable Vref.

Sharp IR sensors use triangulation instead of intensity to measure the distance which makes them a lot less affected by the surface and colour of the object measured as well as sunlight/fluoro lights.

Here's some model numbers to google:

 

[Varunme]

can this be made to work?

https://farm6.static.flickr.com/5267/5594627404_e2ab55647d.jpg

?

 

[Electroenthusiast]

can this be made to work?

https://farm6.static.flickr.com/5267/5594627404_e2ab55647d.jpg

?

Post images as Attachments.
Yes, that circuit will work. You need to adjust the value of pot to a correct extent, and buy a POT of accurate type(i forgot it's name).
You can interchange the terminals based on the output you require.

 

[Gobbledok]

i forgot it's name

A multiturn trimpot

 

[Electroenthusiast]

A multiturn trimpot

Yes Gobbledok...
You can use these, or you can use Ordinary 'Preset' also.

 

[Varunme]

But the circuit is not working for me,
what can be the mistake made by me ?
when i turn the port much, the LED goes always on, so opamp is good isnt it ?
I checked the IR receiver which gives 0.9M ohm with visible and 100ohm in IR,
Transmitter is working also.

 

[ericgibbs]

But the circuit is not working for me,
what can be the mistake made by me ?
when i turn the port much, the LED goes always on, so opamp is good isnt it ?
I checked the IR receiver which gives 0.9M ohm with visible and 100ohm in IR,
Transmitter is working also.

hi,
The emitter and detector are the problem in that circuit, in that the emitter output is continuous, ie: DC driven.

The detector will detect ambient light as well as the IR light from the emitter, so if the ambient light changes, the signal input to the LM358 will also change.

This is why most emitters are pulsed rapidly on/off , an AC signal.
As the detector is also AC coupled, it can be designed to only respond to the AC signal and not the ambient light,, this is what the TSOP17xx detector modules are designed to do.

 

[Varunme]

can any workaround for this to get it working?,
or it force me to go with the tsop1738 ?

 

[Varunme]

can anyone point me towards a working tsop1738 to work with microcontroller,
is the programming while using tsop1738, is like a switch, or there be complex programming ?

 

[Gobbledok]

Hi varunme maybe you want something **broken link removed**

 

[ericgibbs]

can anyone point me towards a working tsop1738 to work with microcontroller,
is the programming while using tsop1738, is like a switch, or there be complex programming ?

You have already got a link to a working version of a TSOP system in Post #9