Hi everybody! I am looking for your support for a "simple" advice.
I am discovering the power of Arduino since few months now and I am blocked for a new project.
I would like to have a cheap proximity sensor that detect people only if they wear a special armband for example. It would be like an infrared barrier which would be activated only of this armband enters the area (between 20 and 90cm from the sensor I would say).
Does this kind of sensor exist? Would it be possible to design it if the armband contains a special metal, or is in a specific color?
Thank you all in advance for your advices!
For an example with a cat: