Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: TrickyNekro on June 16, 2012, 01:37:00 AM
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Hello guys!
It´s really been a long time since I wrote in this forum last time, but I came to a point that I need your help.
I have been working on a university project that requires me to read an analog sensor and sent the data over
the can bus. Fortunately that part is over by now and I need to focus on building a PCB that actually has a small part of
the sensor.
The sensor consists of a foamy pad and two optic fibers, one for sending light to the sensor and the other for
receiving the portion of the light reflected inside the sensor. The amount of the light received back depends on the
pressure on the sensor but that´s not important right now.
What I am asking for is an analog photo transistor that comes with a casing where I hook up the optic fiber.
The thing I really really need is a casing that comes or can accept a phototransistor.
Of course, I need also a casing that can accept a led or comes with a led for the other end/optic fiber.
I am not sure about the light absorption properties of this foamy material, but right now we are using wave lengths
in the red spectrum (from a led).
That´s why I would prefer a casing that doesn´t come with an embedded transistor. But anything is welcomed.
I also haven´t measured yet the diameter of the fiber but it should be less than 1mm, perhaps half or 3/4mm...
But that´s not important right now, what is important though is to find a manufacturer that produces such casings.
Important note, due to the nature of the sensor, the optic fibers can not be changed.
Also for the first time, I really don´t care about the money... University pays, but we need something that we can find.
Farnell preferably, Mouser or Digikey available...
Thank you for your time!
Best Regards,
Lefteris, Greece (now in Germany... ;D )
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Hi,
That´s why I would prefer a casing that doesn´t come with an embedded transistor. But anything is welcomed.
Your best bet is probably to make the housings yourself, that way you can tailor them to fiber as well as LED/phototransistor.
A 3D printer would make it extremely easy, but something like the smallest LEGO bricks would be another possibility.
Line the material with eg. tin foil if needed.
Also for the first time, I really don´t care about the money... University pays, [...]
Must be the German uni? :P ;D
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Hallo! Wie geht´s? It´s been some time since I last wrote here ;-)
That´s why I would prefer a casing that doesn´t come with an embedded transistor. But anything is welcomed.
Your best bet is probably to make the housings yourself, that way you can tailor them to fiber as well as LED/phototransistor.
A 3D printer would make it extremely easy, but something like the smallest LEGO bricks would be another possibility.
Line the material with eg. tin foil if needed.
That´s pretty much what the other guy did. He just used hot silicon glue to do the fiber LED binding but I tend not to
like it very much.
The output swing of one sensor is from 0.3V to 1.4V or something close and for the other pad,
the output swing is from 0.8V to 2.1V and that´s not good.
Of course I can do software compensation but I´m losing one the ADC resolution. And the whole thing
is based on an industrial application, so I need to find a sturdy viable, easy to use solution. But even if it
was for me, I would get it this way no matter what. It´s optics, some degrees error can ruin your day, and
I really don´t want this on the final result.
I am thinking of using something like these, haven´t found the right one just yet but I think I´m on the right track:
Hell it doesn´t allow me to post the Farnell link, I don´t know why...
But anyhow I was searching at the Fiber Optics category of Farnell, they have many things there that
may suit my needs. 8)
Also for the first time, I really don´t care about the money... University pays, [...]
Must be the German uni? :P ;D
Cut poor Greece some slack :P It´s not that bad after all, but still yes, I´m here in Germany,
actually in Bremen doing my Diplomarbeit at the Uni. And believe me it´s one of the best
choices I ever made. The only thing that really bothers me is the weather. Apart from that,
everything´s more than fine! The bad thing is that I´m here as an Erasmus student and that
means only one semester. But I´ll try to come back for master and perhaps PhD, I don´t
know yet. It depends on many factors. But yes, apart from having a large budget here, they
also know very well what risk capital is, and I really made some use of it already! :P