Last time I posted a question I got a few helpful and educated responses, but also a fair share of belittling and frankly cruel ones too. This time Im hoping for the positive and enlightening responses.
Here's my question: What type of sensor would work best for this application? I have a five gallon bucket, and what I want to do is mount some sort of device on the rim that will alert me when a tennis ball gets drops into it, a particular tennis ball of my choosing. This is something I want to build for work as a quality control "test" meaning I want to insert a flawed tennis ball into the production line and see if it makes it past quality control. The plan is to toss this one flawed ball in with about ten others and let me know if the flawed ball made it through quality control. Ive done a lot of research and am still scrathing me head on this one. What I've been thinking about is possibly RFID, but I'm not sure if RFID has a nominal range of 2 feet. Is there something out there (there has to be!) that I can insert into a ball which will trigger an alarm on the bucket when it passes the rim of the bucket? Whatever target I put in the ball has to be small (and preferably non-powered) but the reader or device on the bucket can be plugged in or battery operated. I wish I knew more about sensors, which is why I'm asking you good folks for any ideas. Thanks a bunch!
the type(s) of fault(s) you are looking for? For mass, weigh it. For color, there are color sensors. For size, maybe a couple of switches at the Go/No go sizes. I have no current idea on how you would Go/No go for fuzziness.
Even better, size could be a couple sets of almost parallel bars to allow large balls to be sent to one side and small balls to the other.
Really though, without knowledge of what you are testing for you still won’t get the kinds of answers you are hoping for.
If I understand correctly, you are looking for a needle in a haystack by looking at each piece of hay to see if it is, or contains a needle. That said, RFID is/was inexpensive. Yes, you are going to have to be semi-close to the ball to read the tag, but, I have seen tutorials on how to build a reader online.
What about “painting” the bad ball with some kind of dye that shows up with something like a black light and then use a camera and maybe OpenCV to look for the glowing ball. Someone may have mentioned that in the previous post. I only scanned it.
RFID is widely used for this purpose in shops (ever noticed the two antennas by the entrance?), and there are lots of ready solutions for that.
I like birdmun idea of using paint that is only visible in UV light. You could perhaps also insert a small magnet in there and use a hal sensor? Radioactivity and a geiger’s counter are probably out of the question…
All other solutions that I can think of involve some sort of small battery in there, so probably not good for you.
My previous posts are basically asking the same thing that I gave up on over a year ago. And No Maxhirez, it’s nothing propietary I’m working on, because I’m not trying to invent a new technology. I think RFID is the way to go, and since the bucket is less than 60 cm I think I’ll just use a long range RFID reader and just put a passive tag inside the tennis ball Does anyone know how to modify an RFID to sound an alarm when it reads a tag a tag within the vicinity?
I recently recieved an RFIDuino reader and installed it on my arduino UNO 3. It works! But, I made a mistake. In reading the read range on Trossenelectronics data sheet I confused cm with mm, therefore the range is only <4" when I was expecting nearly 20".
However, im working through projects from the arduino starter kit and and absolutely pumped I got the rfid reader to work, enough so I believe I can still yet achieve my final goal.
My new question to you good people is this: are there any roads of thinking someone can guide me down to incread my read range to 2 feet or close to it?
I’ve been looking at possibly using active RFID tags, but prefer passive since they aren’t battery powered. The RFIDuino operates at 125 khm and I’m thinking at higher frequency can increase read range also. I’m researching UHF RFID but they seem to be outside my budget. Any ideas, greatly appreciated.
