Working with a simple IR sensor

[sabkumar.r]

Hi,
My aim is to make a simple sensor that detects an Object's Movement. I have an IR LED with a photodiode as a detector. I intend to make IR radiation from the LED fall on the Photodiode always. So, when an obstacle comes in between, there will be a change in the diode current which can be used to detect the obstacle. Is my approach correct??

I am just trying to learn and am doing this as a hobby.Any help will be really appreciated.

Thanks,
Sabareesh

 

[milind.a.kulkarni]

First of all you need have some constants to your system for a example -
- Characteristics of target like reflective object etc.
- Maximum Distance allowed to move the target
- Direction of moving the target
- No of Ir Sensor you are planning to use
etc....

After this let consider it is a planer system i.e. the movement in x and Y plane only what you try having two approach -

1) You can mount two IR LEDs on the target in the orthogonal manner and keep two or four sensors ( IR detectors ) around the target in South - West - North - East fashion... but in this case you need to have power to the IR LEDs provision made in target itself .... some thing like battery....this is easy and reliable and works most of the time based on the receiver intensity that you capture...
2) you can have IR LED away from the target and reflecting the IR radiation from the target ....detected by IR sensor / detectors based on the position of your IR radiation magnitude you can detect the motion of target....complicated design and most of the time experimental....

Good Luck

 

[sabkumar.r]

First of all you need have some constants to your system for a example -
- Characteristics of target like reflective object etc.
- Maximum Distance allowed to move the target
- Direction of moving the target
- No of Ir Sensor you are planning to use
etc....

After this let consider it is a planer system i.e. the movement in x and Y plane only what you try having two approach -

1) You can mount two IR LEDs on the target in the orthogonal manner and keep two or four sensors ( IR detectors ) around the target in South - West - North - East fashion... but in this case you need to have power to the IR LEDs provision made in target itself .... some thing like battery....this is easy and reliable and works most of the time based on the receiver intensity that you capture...
2) you can have IR LED away from the target and reflecting the IR radiation from the target ....detected by IR sensor / detectors based on the position of your IR radiation magnitude you can detect the motion of target....complicated design and most of the time experimental....

Good Luck

milind.a.kulkarni, Thanks a lot for ur response.
I am planning to use two sensors side by side so that i can detect the direction of movement of the object. The object's reflective characteristics are fixed. And it is a planar system. The problem is I cant place the LEDs on the target. Please have a look at the attached file.

Detection by the sensor is done as follows:
1) When there is no obstacle, IR from the led falls on the sensor. This gives a steady state current.
2) when there is an obstacle in between. The amt of radiation now falling on the sensor would be different and hence a different current.

This difference can be used to detect the target.
would that work?

 

[milind.a.kulkarni]

This is perfectly fine...... only the thing that you need to keep in the mind in this case is IR Detector should not receive any IR radiation ....some time what happens if you develop this system and In case if you are walking with TV remote made on directing towards you IR Receiver... It will still receive the IR radiation and will make system fail....Now the second case is the distance between the IR LED and IR Detector.....if it is too large then IR LED transmit IR waves in the radial manner....so after some period of time I mean after aging too you may get fails detection so general trend in this kind of development is develop close distance circuits and protected from external IR radiation....

I will recommend you to read the link below-
**broken link removed**
https://extremeelectronics.co.in/robotics/obstacle-avoiding-robot-using-avr-atmega32-–-part-ii/

Hope this will be helpful to you....

Good Luck

- - - Updated - - -

This is perfectly fine...... only the thing that you need to keep in the mind in this case is IR Detector should not receive any IR radiation ....some time what happens if you develop this system and In case if you are walking with TV remote made on directing towards you IR Receiver... It will still receive the IR radiation and will make system fail....Now the second case is the distance between the IR LED and IR Detector.....if it is too large then IR LED transmit IR waves in the radial manner....so after some period of time I mean after aging too you may get fails detection so general trend in this kind of development is develop close distance circuits and protected from external IR radiation....

I will recommend you to read the link below-
http://www.coregravity.com/html/detecting_obstacle_with_ir__in.html
http://extremeelectronics.co.in/robotics/obstacle-avoiding-robot-using-avr-atmega32-%E2%80%93-part-ii/

Hope this will be helpful to you....

Good Luck

 

[sabkumar.r]

thanks a lot! the articles were really helpful. I look forward to actually implementing them!!