Hey guys,
is it possible to detect different colours (materials) for a line following robots with an IR sensor. Im not talking about the detection of the difference between white and black, im talking of a third colour, for example red or another colour (material). The idea was to make the robot stop or do a task if he detects that colour.
Technically the IR sensor measures the reflected IR wavelength he gets back. Different colours should reflect the IR light more or less and a detection could be possible.
Am i wrong?
We were thinking of a sensor like this:
eBay
This sensor seems to have an analog output besides the digital one we wouldnt use since it can just have two states (1 and 0).
eBay
This sensor just has a digital output and wouldnt really work i guess?
Thanks for your help guys!
Technically the IR sensor measures the reflected IR wavelength he gets back. Different colours should reflect the IR light more or less and a detection could be possible.
Am i wrong?
Yes.
This is because the returned light also depends on the nature of the surface and the distance of the reflecting surface to the sensor and also the angle of the surface to the incident light. You normally need sensors of three different wavelengths to determine a colour, even if some of those sensors may be in the IR region. It is common on interplanetary space probes to have four or more images taken in different wavelengths and almost always an IR wavelength is chosen for one of them.
Alternative you can have one sensor and three ( or more ) wavelengths of illumination.
Grumpy_Mike:
Yes.
This is because the returned light also depends on the nature of the surface and the distance of the reflecting surface to the sensor and also the angle of the surface to the incident light. You normally need sensors of three different wavelengths to determine a colour, even if some of those sensors may be in the IR region. It is common on interplanetary space probes to have four or more images taken in different wavelengths and almost always an IR wavelength is chosen for one of them.
Alternative you can have one sensor and three ( or more ) wavelengths of illumination.
Mike thank you very much for your help! So what if we use different material? The Angle and the distance shouldnt really change, since the robot is fixed to the robot.
Any other ideas how we could show the robot that he just entered a different colour?
Since a colour sensor needs 4 Digital inputs and 1 output its not really adequate for our project.
since the robot is fixed to the robot.
What?
Since a colour sensor needs 4 Digital inputs and 1 output its not really adequate for our project.
No that would be 4 analogue inputs and 1 digital output
Or
You could use 3 or 4 digital outputs and one analogue input.
You might try the Adafruit color sensor breakout. Seems well suited to your project.