Hello. So I reread the rules and am going to pose my dillema as specifically as I can. I've been researching it for a couple weeks and am still stumped, so please bear with me...I'm just a beginner.
Here is the problem I am trying to solve, posed metaphorically.
What sensor exists, that would allow you to detect a particular tennis ball being dropped into a bucket, only that tennis ball, and no others? What would I have to attach to the bucket AND that one tennis ball that could detect and alert me it just passed into the bucket?
Here's my problem. RFID, and a RFID reader, would be too expensive. The range also isn't great enough, as it appears most RFID readers/tags are only effective when >100mm away from one another. I also need to be able to throw this device together fairly cheaply (i.e. less than twenty bucks or so) Can anyone clue me into some concepts that can guide me in my research? Any help, as always, greatly appreciated. Any specifics willfully given. Thanks you
You obviouslt know what youre talking about, and I have come accross hall effect sensors, but my range of operation would need to be about two feet. Also, for the sake of what I’m trying to build, any visual modes of operations would have to be eliminated. Imagine all the balls are the same, better yet, imagine your dropping them into a bucket in pitch blck darkness. Something would have to be affixed to the one ball to set off an alert. I feel like I’m soo close! thank you 6677 for your input, but any more ideas??
How big is the bucket, in what range have the sensor to work?
Magnetic (hall effect) is not very good for big distances, RFID as well. REED switch in the bucket what comes to my mind. Or a camera as 6677 mentioned. A marking on the balls surface and check the incoming balls for that pattern.
For 20 bucks it’s quite hard to suggest something because the Microcontroller would probably cost already more than $US10.
we use fluorescent markers in certain microscope work - the marker is activated by a particular wavelengh of light hitting it and then it emits light of a different wavelengh.
a couple of light filters would do the trick (together with a light emitter and reciever)
