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Author Topic: setting up a reflective object sensor for dummy's  (Read 27058 times)

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Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #50 on: February 03, 2008, 05:19:38 PM »
oh thought you were meaning the 12v on the Index Input, what s12signal are you meaning?
Hood

Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #51 on: February 03, 2008, 05:34:54 PM »
Just read back and all I can see that you would be talking about with the 12V is indeed the Index signal. If this is correct then hopefully you have not done any damage as you should be feeding the optical switch with 5v.
Hood

Offline Chip

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Re: setting up a reflective object sensor for dummy's
« Reply #52 on: February 03, 2008, 05:38:13 PM »
Hi, Chris

Look like the on / off is good, Must be a Noise issue,  The Capacitor may get it working.

Thanks, Chip

Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #53 on: February 03, 2008, 05:44:50 PM »
Chip what are we talking about here? where is the 12V?
Hood
Re: setting up a reflective object sensor for dummy's
« Reply #54 on: February 03, 2008, 05:46:20 PM »
well I am feeding the switch 12v but I have a couple of other optical switches on my mill running off the same board. they handle the 12v alright with  no problems. The breakout board switches the voltage back to 5v before it goes into the parallel port. I really have no idea why they use 12v power on these boards but it is what it is I guess.
so yes the input signal is 12v but it is working just fine. I still have a 220 ohm resister in line with the LED and It hasnt burned out so I imagine it will be fine.
Im leaning toward noise as the problem. will get back to you guys tomorrow when I have a chance to put a capacitor on it to see if it quiets it down.
Chris
didnt win the O scope by the way. guess I will keep looking for one.

Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #55 on: February 03, 2008, 05:51:38 PM »
Quite a few breakouts use 12V for power but the I/O is 5V, maybe your board is different I dont know. Anyway if you need to use 12V you may be better increasing the resistor to 500 Ohms.
Hood

Offline Chip

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Re: setting up a reflective object sensor for dummy's
« Reply #56 on: February 03, 2008, 05:56:31 PM »
Hi, Hood

The 12 volt's is on the BoB input side, Printer port side opto isolated.

Hook your Skype back up and give me a call sometime.

Thanks, Chip
Re: setting up a reflective object sensor for dummy's
« Reply #57 on: February 03, 2008, 06:06:48 PM »
well I dont really think my board is anything special. perhaps I have it wired wrong but I dont see how I would end up with 5 volts if Im using a 12 v power supply to the switch. I will atach a drawing of how I have it wired up.
Chris

Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #58 on: February 03, 2008, 06:15:03 PM »
No, seems OK, I didnt realise that Bobs breakout took 12V on the inputs, most just take 5V inputs.
Hood
Re: setting up a reflective object sensor for dummy's
« Reply #59 on: February 04, 2008, 06:03:03 PM »
ok, some success. I went out and got a capacitor and put it in between the signal wire and ground. turned it on and and I was getting the same jumbled mess of numbers all over the place but I notice that it wasnt so drastic as before. so I slowed the spindle way down and I started getting a semi stable reading from the tach. stable in that it held fairly steady around 200 rpm but about once a second it would flash a really high number and then return to the stable number. So I took the slotted disk off and widened the slot to about an inch wide and put it back on. now I was getting a fairly stable tach reading with the exception of the sporatic numbers every second or so up to 2000 rpm. which is about my max anyway. so I messed with the debounce and that did nothing. then I thought I might be getting extra pulses from the shiny edges of the aluminum wheel where I had cut it on the saw. so I masked them with electrical tape and that seemed to have a slight effect (or it could be in my head). so as It stands right now Im getting a reading that is in the ballpark but I'm either still getting a little noise or some stray light to the sensor perhaps.
anyone have any thoughts on how to tame this thing a little more. also how does one calibrate the tach. or am I just supposed to assume it is correct? and does anyone think that a slightly bigger cpacitor filter would help?
close but Im not celebrating yet.
Chris :-\