Opto slot interface

[cadcamboss]

Hi all
I am trying to construct an opto slot interface for controlling a motor driven mechanism. can't find a circuit anywere. can anyone help?

 

[papaof2]

Are you trying to detect the presence/absence of something in the slot (limit switch) or count pulses from a slotted wheel turning in the slot?

Presence/absence could be as simple as checking an input pin for high/low. Counting pulses is likely to be more complex.

Tell us more.

John

 

[Tom2000]

Hi all
I am trying to construct an opto slot interface for controlling a motor driven mechanism. can't find a circuit anywere. can anyone help?

You might try the circuit below.

The exact resistor values will depend upon your specific opto interrupter. If you can't find a data sheet, try 470 ohms for the LED current limiting resistor and 4k7 for the collector load resistor.

With nothing in the slot, the circuit will output a low to the Picaxe. With the light path interrupted, a high.

Good luck!

Tom

 

[evan.F]

Hi cadcamboss

I've attached the circuit I am using for my slotted rotor, it gives a nice TTL signal.

And here are the links where I got it from.

http://www.alanmacek.com/robot/
http://www.sensi.org/~svo/shaft_encoder/

 

[smartpartzzkidd]

could anyone supply a snippet of code for counting incoming pulses from the opto-interrupt?

 

[Andrew Cowan]

count, pin, time, variable

main:
count, 2, 2000, w0
serout 7,N2400,(#w0)
pause 8000
serout 7,N2400,(254,255)
goto main

Made that up - not sure if I got the LCD code right.

A