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Author Topic: setting up a reflective object sensor for dummy's  (Read 27048 times)

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Re: setting up a reflective object sensor for dummy's
« Reply #40 on: February 03, 2008, 12:44:27 PM »
Hi, The capacitor will need to be placed as follows, one wire of the capacitor connected to the signal wire and one wire of the capacitor to 0v wire/ground. It is best if the capacitor is connected as close to the sensor/switch as possible.

This is called parallel connection whereas "in-line" is called serial connection and will not work because the capacitor connected "in-line" would only pass AC signals which is not what is needed.
Re: setting up a reflective object sensor for dummy's
« Reply #41 on: February 03, 2008, 01:07:10 PM »
ok makes sense. now I take it the capacitor has a pos lead and neg lead. and Im assuming the neg lead goes to ground (green wire) and the pos lead goes to the signal wire ( blue wire).  and I will cut the leads as short as possible to get the capacitor right next to the switch. How close am I.
Chris.
« Last Edit: February 03, 2008, 01:47:11 PM by Chip »

Offline Chip

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Re: setting up a reflective object sensor for dummy's
« Reply #42 on: February 03, 2008, 01:34:43 PM »
Hi, Chris

Capacitor's, Many flavor's, The one you have may work fine, But the type "Cjmerlin" was referring to, I think, Looks like a Dime or smaller with leads coming

out of the side/edge, Ceramic, Non polarity sensitive type.

Thanks, Chip

PS:  Were waiting for, "It work's !!!!"
« Last Edit: February 03, 2008, 01:53:25 PM by Chip »
Re: setting up a reflective object sensor for dummy's
« Reply #43 on: February 03, 2008, 01:50:58 PM »
Yep, Chris is nearly there, The capacitor I was referring to is a non polarity type (eg can be connected any way round). As to shortening the leads maybe I wasn't clear enough. It isn't necessary to do that, only to make the connection near the sensor/switch end of the cable and not near the end of the cable that connects to the breakout board.


Hope this helps.


PS: I've just read through this thread and I just wondered if you had use of an oscilloscope you could have tracked the problem down in 5 minutes.
I have one and found it invaluable just for problems like this. I looked on US Ebay and one could be had for less than $20 and learning the basics of how to use them is not that hard, it's just like using a multimeter.

Just a thought!
« Last Edit: February 03, 2008, 02:30:37 PM by cjmerlin »
Re: setting up a reflective object sensor for dummy's
« Reply #44 on: February 03, 2008, 02:46:02 PM »
well Im not going to be able to mess with it till I can get down to the electronics store tomorrow and pick up a capacitor.

cjmerlin. Can you link me to the O scope on ebay you where refering too. I do think it will be in my interest to own one.

Chris

Re: setting up a reflective object sensor for dummy's
« Reply #45 on: February 03, 2008, 03:15:29 PM »
Hi, I just did a quick look on Ebay and there is a large difference in price but all you'll need is a simple one so try bidding for this one Ebay item no 130193806388. If not, be patient and a cheap one will come along eventually.


Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #46 on: February 03, 2008, 04:06:01 PM »
I would advise you to try and get a dual trace scope, much more use especially as you progress. Not sure what the prices are like in the USA but I picked up an immaculate dual trace scope for about £30 ($60). I have seen them cheaper but this was an ex Post Office one so I knew it would be half decent ;)

Hood
Re: setting up a reflective object sensor for dummy's
« Reply #47 on: February 03, 2008, 05:08:52 PM »
Hey Chip, I took a quick moment to put a vltmeter on the signal input. Im getting about 12 volts when the signal is on and(correction .01) volt when it is off.
If that helps.
As for the scopes. what would be a use for a dual trace as aposed to s single trace scope??? just curious, all the dual trace seem to be a little pricy right now.
Chris
« Last Edit: February 03, 2008, 05:16:16 PM by guynamedbathgate »

Offline Hood

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Re: setting up a reflective object sensor for dummy's
« Reply #48 on: February 03, 2008, 05:14:00 PM »
you sure your meter is right? if yes then you have serious problems, should be 5v.
Dual trace are very handy especially if you have a servo system, it lets you look at the A nd B signals of the encoder, if you have differential encoders you can look at A+ and A-, also if you have AC servos and you need to align the Hall from the encoder to the motor windings you need a dual trace scope.
 If you cant get a dual trace at a decent price get the single trace and just keep an eye out and snap one up when it comes along at the right price.
Hood
Re: setting up a reflective object sensor for dummy's
« Reply #49 on: February 03, 2008, 05:18:12 PM »
why do i have a serious problem? I have a 12 volt supply on my break out board. why wouldnt the signal be 12 volts going back into the board.