Hi
I need to use an Arduino with some sort of reader to read when a object is rotating. Take a look here:
This video shows what im trying to read, as it begins moving a few seconds after the video starts .. There seems to be two things i can read, either the silver half disc or the white cog wheel thing that also spins. I'm just not sure what i should get to read this.
Any suggestions ?
If you read the silver half-disc, you can count resolutions. If that works for you, I think it's going to be easier to get a photo-eye or possibly a prox sensor (ferrous?) to "see" that opposed to anything else.
Perehama:
If you read the silver half-disc, you can count resolutions. If that works for you, I think it's going to be easier to get a photo-eye or possibly a prox sensor (ferrous?) to "see" that opposed to anything else.
Thanks for your reply! By Photo-eye do you mean something like this ? https://www.ebay.com/itm/Photocell-GL5528-5mm-Arduino-Raspberry-sensor-brightness-detector/283078960654?hash=item41e8d2260e:m:mjYLzsEQHl8490qRoWrME5w:rk:11:pf:0
It's possible that a laser diode might work if you could mount it in such a way to hit the moving part AND reflect back at an angle that causes it to line up with
photo sensor to detect the beam. I would recommend you read one as COARSE (the rotating metal disk)
and the other as FINE, the small white/black rotating disk.
The QRE1113 sensor would probably work for that task. It may be confused by the plastic cover but I expect it will work if it is held directly against the cover.
A ZMID5201 sensor could read the position of the metal disc to high accuracy. You might be lucky and just use the development kit PCB but you probably would need a custom PCB to use that sensor properly.
djda9l:
Thanks for your reply! By Photo-eye do you mean something like this ?
Absolutely not! That detects light. You need something that detects a change from no disk to disk. Keyence, Banner, Omron etc. all make reflective fiber optic photo sensors that will do the job of detecting disk or no disk. They can run anywhere from $75 to $500+ depending on other features and factors.
Possibly a QRB1134 reflective sensor;
https://www.newark.com/pdfs/datasheets/Fairchild/QRB1134.pdf
djda9l:
Thanks for your reply! By Photo-eye do you mean something like this ?
I take back my "NO." It may be possible to use something like you have linked. You would need to get one, get a read with it looking at the disk and get a read with it looking at the no disk. If there is a distinction in light value returned from the sensor, it will work. The units I mentioned from automation manufacturers have this type of calibration built in, along with fiber optic focus for high precision. It may or may not be possible with what you have linked. Only a real-world test would answer that for you.
See page 2 of this datasheet
The device is called a "Reflective object sensor" which is ideal for your application. The only variable is
the form factor or package size. You may need a much smaller package , such as a small surface mount package to get the correct focal length or target distance.
See page 4 of this datasheet
see graph title: ["Distance to Reflective Surface-inches"] (optimum = 0.3")
This looks like a better choice than the other one.
Hi,
Welcome to the forum.
What you are trying to do, has been done before.
google reading residential water meter with arduino
Tom... 
Maybe have a look at one of these if you are planning to have a white or silver pacth on a dark disc, or a dark patch on a pale coloured disc.
You could make a beam-breaker if your disc has spokes, just take into account the number of spokes. (Simplest is probably a tight-beamed LED shining through the disc onto a LDR which is shielded from ambient light)