Looking for "Optical Encoder" to Count Wheel Revolutions

4

4jaba6

New Member
I am doing what title says.
Am not having much success on major supplier searches..."SparkFun, Banggood" and several others. Can someone recommend an encoder and source?
In past, I used a Zagros encoder, but now can not find it.
( I suppose if I am directed to an optical encoder that works for my robot wheel, I would be posting again for instructions (tutorials ) and code ).

TIA ( Thanks in Advance )
 
A

AllyCat

Senior Member
Hi,

It depends on many factors such as size, speed, ambient lighting, etc., but you could search for Vishay-TCRT5000 on ebay. For me, all the links on ebay.com appeared to be for Chinese sellers, but there were plenty locally-sourced on my ebay.co.uk (had I needed a few quickly).

We briefly discussed them in a recent thread, although in that case the OP then chose to use Hall (magnetic) sensors instead.

Cheers, Alan.
 
4

4jaba6

New Member
AllyCat said:
Hi,

It depends on many factors such as size, speed, ambient lighting, etc., but you could search for Vishay-TCRT5000 on ebay. For me, all the links on ebay.com appeared to be for Chinese sellers, but there were plenty locally-sourced on my ebay.co.uk (had I needed a few quickly).

We briefly discussed them in a recent thread, although in that case the OP then chose to use Hall (magnetic) sensors instead.

Cheers, Alan.
Click to expand...
Alan,
Thanks for the quick response!
Based on your reply, am trying to decide between the TCRT5000 and a Hall Effect sensor like the A3144.
Could take awhile. Sure miss the OPB704WZ by OPTEK.....
LATER....Found them! DIGIKEY and others.

https://www.digikey.com/product-detail/en/tt-electronics-optek-technology/OPB704WZ/365-1677-ND/1637047?utm_adgroup=Sensors & Transducers&utm_source=google&utm_medium=cpc&utm_campaign=Dynamic Search&utm_term=&utm_content=Sensors & Transducers&gclid=EAIaIQobChMIsLqajrmv6wIVlYvICh0e1QVGEAAYAiAAEgI9N_D_BwE

I think I shall stick with these because found them very usable in past.
Don't right now want the learning curve of the other two.

Thanks for your assistance and hope I not take up too much of your time.
Sounds like from your recent thread link that the TCRT5000 might have been going down of a bit of a "rabbit hole" with the ambient light issues.

John
 
premelec

premelec

Senior Member
FWIW way back on this forum a member offered a nice optical disc printout generator program - you could spec type of coding and number of 'slots' per turn... it's somethere in my files... ;-0
 
erco

erco

Senior Member
Big subject. Reflective optical encoders are simple in concept but can be tricky to scratch build & implement. I have built many, there is always some experimentation and twiddling to be done to get a 50/50 black/white signal. The striped disk needs to have its stripes sized to the encoder's "view", and the encoder needs to be properly located to have the right view of the wheel encoder (distance, orientation, etc). The wheel needs to be mechanically true (no wobbling), and the encoder disk needs to perfectly centered on the axle. The black stripes need to block the IR or visible light, the white needs to reflect it. I find that a laser printer disk works, but an inkjet doesn't. Current through the IR LED needs to be adjusted, and I generally use a simple voltage divider as a sensor (just the right resistor in series with the phototransistor), and adjust that output to play directly to a Picaxe input pin's high/low transition voltage (1.2-1.4V, depending on Vdd). Minimal hardware but lots of work to get it dialed in.

 
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