ch_91:
Hello,I need help deciding which sensor would do the job. The problem is I am doing a project with a Arduino Uno what is 'acting' like a desktop pet where I have 2 LEDs which notify the user that if one goes off it wants some food and the other if it wants a drink. I have made 2 small physical objects that will act as the food and water. And when you press them against the device the LEDs will go off.
Is there a sensor or something that will know the difference between each object? I was thinking of using a RFID reader and placing the tags into the 2 objects. Will this work, and/or is there another way I can do this?
Sorry if it sounds confusing.
Thanks!
You don't say how big your 'food' and 'water' objects are. I'll assume that they are 2" long.
For a cheap solution, place two small magnets in one (say food) 2" apart and another two in the other (say water) 1" apart. In your 'receiver' place three magnetic reed switches with 1" gaps between them (at 0", 1" and 2") . Wire switch 1 in series with switch 2 and also switch 1 in series with switch 3, a "Y" formation. When brought close enough the 'food' will activate switches 1 and 3 and 'water' will activate switches 1 and 2, so the output (switch 2 or switch 3) will tell the 'receiver' which has been brought near.