Hello,

I wonder if the glitter would scatter the light from the sensor to much.

Bertus

There is also the 3M reflective tape, I was thinking the glitter paint may replicate this?
Max.

 

Hello,

As far as I know the 3M tape is using glass particles in the tape.
Glitterpaint has likely larger parts that will scatter more.

Bertus

 

One other route is to use a ferrous detect (non-magnetic) style proximity sensor on the spokes.
Max.

 

One other route is to use a ferrous detect (non-magnetic) style proximity sensor on the spokes.
Max.

View attachment 162060

Another good possible. I have used the AIRPAX Magnetic sensors on numerous systems. They are good for picking up teeth on a gear and should work fine for the above task.

Ron

 

One other consideration on the resolution is if it is just for RPM monitoring/indication or RPM control is considered, if the latter, then closer control is achieved using a multi count/rev method.
If using a one/turn retro-reflector, use a single small white paint stripe or tape, not half the wheel.
Also I have tested the QRE1113 I used for any effect of incidental light that might be present, but I did not detect any detrimental effect from the sources I used.
Max.

The reason that I suggested half the wheel is that at higher speeds the pulse may be too short for some counter circuits. Since paint is both cheap and easy, the 50% coverage would produce closer to a square wave and be more reliable. Admittedly this is a bit more than a perfect counter needs, but a very easy way to reduce the possibility of a problem. At the time I posted that suggestion I had no idea what the application was, and some applications include very fast motor speeds.

 

Another good possible. I have used the AIRPAX Magnetic sensors on numerous systems. They are good for picking up teeth on a gear and should work fine for the above task.

Ron

I have quite a few 12mm dia in my surplus stash, Baluff, Turk etc.
Also another source is an auto wrecker for the Honeywell 1GT101DC gear timing detector.
Max.

 

I have quite a few 12mm dia in my surplus stash, Baluff, Turk etc.
Also another source is an auto wrecker for the Honeywell 1GT101DC gear timing detector.
Max.

I have one of those from one of my old trucks. It was never quite the same after working its way into a gear.

Ron

 

What do you think of this? Is it correct? I will use this reflective sensor. Another info is that the motor will be enclosed, so ambient light should not disturb. I haven't tested it yet.

 

What format is the link in, I cannot see it?
The white tabs should OK.
Max.

 

Should be easy to detect. Spacing of the reflective detector is critical.

 

What do you think of this? Is it correct? I will use this reflective sensor. Another info is that the motor will be enclosed, so ambient light should not disturb. I haven't tested it yet.

The application of reflective patches looks reasonable, but it may be that the shiny black paint also reflects light. Only testing will determine that. And it might possibly be that it works perfectly up to some speed. You do need to be certain that the mount for the sensor is stable and rigid.

 

I see it now, I believe that is the same one Roman Black used on his SuperPID for router control up to 20krpm.
Max.

 

Thanks you all. I will test it to see the performance. And yes, I will take into account the spacing of the sensor.

 

The application of reflective patches looks reasonable, but it may be that the shiny black paint also reflects light.

I wondered myself about that shiny black. I was not sure if it could cause issues.

 

I wondered myself about that shiny black. I was not sure if it could cause issues.

You will know when you test it. I have used a piece of reflective tape doing test on some shiny stainless steel shafts and it worked. I guess it all comes down to testing it.

Ron

 

Some thoughts from the past. I've used the photo transistor as an emitter follower with 100k emitter R
feeding into a non inverting gate for signal shaping. Motor whizzing around at 20 RPM but not allowed
to make a full rotation. Also used a comparator and emitter follower.

 

Avoid having alpha1 being equal to alpha 2 so that light from the shiny black surface is not detected

 

I'm having some issues. First, I have a setup very similar to one shown below. There are some differences. The voltage is 3.3V. The collector pull up resistor is 10k and the diode current-limiting resistor is 174 ohms. What I find strange is that without the sensor connected, (just the pull up resistor) I'm measuring 1.4V at Vout, which is the microcontroller input. I'm getting nothing from the sensor also.

Update: The sensor is activating, I just need to place it well. But I'm still confused about the pull up voltage, should be 3.3V.

 

What is the ambient light level?
The sensor may be reacting to that. What is your reading when it is placed in the dark?

 

Did you block the detector side completely?
Max.