Is this possible?

Thread Starter

johncena

Joined Aug 15, 2010
32
A microcontroller based sensor that can measure a given board (ex wood, cardboard, pcb) 2d only

ex. when you placed a PCB inside it, it will measure the PCB's current size (or area) and then show it to the user via Graphics LCD
 
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praondevou

Joined Jul 9, 2011
2,942
A microcontroller based sensor that can measure a given board (ex wood, cardboard, pcb) 2d only

ex. when you placed a PCB inside it, it will measure the PCB's current size (or area) and then show it to the user via Graphics LCD
Is this something you saw, or something you want to build?
What would be the maximum dimensions to be measured? What the precision?

Do you want to buy a sensor off-the-shelf?

I'm sure you didn't think about something as sophisticated as this laser scanner,right?:D
http://www.creaform3d.com/en/handyscan3d/handyscan3d-video.aspx
 

Thread Starter

johncena

Joined Aug 15, 2010
32
something i want to build, the max will be 12 by 12 inches only, precision is a must actually.. although it is good to detect only the copper side of the PCB, not the plastic/non conducting side of the PCB.
 

luvv

Joined May 26, 2011
186
I's not as cool as lasers but you could use a box w/ raised contacts.

One positive contact in the center of the grid, then its just a matter of calculating the resistance for a given board size.

Or the number of contacts conducting..w/e

OR a grid of phototransistors/resistors on the bottom and bright light over head..

Think it just comes down to the ability to map a grid w/ a pic, of which i know jack squat...but im sure it's doable.

Interesting project tho i would like to see what you come up w/.
 

mcgyvr

Joined Oct 15, 2009
5,394
How will this be any faster than just measuring it with a micrometer/caliper?
What "precision" do you require?
 

Thread Starter

johncena

Joined Aug 15, 2010
32
How will this be any faster than just measuring it with a micrometer/caliper?
What "precision" do you require?
we would like to measure also the surface area of irregularly shaped PCBs, then the microcontroller will output the image/coordinates/measured size to Graphics LCD
 

Thread Starter

johncena

Joined Aug 15, 2010
32
I's not as cool as lasers but you could use a box w/ raised contacts.

One positive contact in the center of the grid, then its just a matter of calculating the resistance for a given board size.

Or the number of contacts conducting..w/e

OR a grid of phototransistors/resistors on the bottom and bright light over head..

Think it just comes down to the ability to map a grid w/ a pic, of which i know jack squat...but im sure it's doable.

Interesting project tho i would like to see what you come up w/.
since PCB is made up of Copper (plain PCB, not etched), i would like to run a current on it then use a current sensor or something like that, that will scan the board on a gantry.
 

mcgyvr

Joined Oct 15, 2009
5,394
Not sure where you are going with the current sensor..

Again..What precision do you require?
Whats the real end use? Who just gets small random un-etched copper clad in irregular shapes that they need to accurately determine surface area..
Maybe you could do it by weight instead
 
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williamj

Joined Sep 3, 2009
180
I just read an "Instructable" were someone hacked a digital caliper and added a larger external readout. Is that what you're talking about?

williamj
 

luvv

Joined May 26, 2011
186
Not sure where you are going with the current sensor..

Again..What precision do you require?
Whats the real end use? Who just gets small random un-etched copper clad in irregular shapes that they need to accurately determine surface area..
Maybe you could do it by weight instead
Think what he is talking about is the point to point resistance of the copper.

That i think would be very hard to do considering the very small resistance differences you would be dealing w/.

That along w/ variables like thickness of the clad,purity of it etc etc.

What i was talking about was the resistance of a many matched resistors in a grid.
The more resistors in contact the higher/lower the resistance.

These methods would only give a estimation of area not dimensions.

Another idea i came up w/ is along the same lines in it will only give area but would be much more reliable and cheap and easy.

Solar panel, light above the box sets the base voltage any object placed on the panel would decrease the output of the panel and you could work out a formula to establish area.

If you want dimensions, you are going to need lines.

Lines of conductors of some sort be it simple copper contacts or photo transistors, photo diodes in a grid array.

Then the pic would only need to read a high or low state on it's I/O ports

I really like this project, tempted to build something just for giggles:D

Please don't abandon this thread till you decide on something i wanna see where it goes :(
 

mcgyvr

Joined Oct 15, 2009
5,394
The answer is highly dependent on the precision/accuracy required.
Chances are a 2d laser/profile scanner/ccd imaging camera would work..
Or 3d digitizer arm (or gantry mounted probe)
Or even something like whiskers/microswitches that you move the object over and calculate size based on movement speed/switch displacement.

But
Precision ain't cheap and cheap ain't precision.
or my favorite
Better/Faster/Cheaper..pick 2
 

Thread Starter

johncena

Joined Aug 15, 2010
32
Another idea we came up with is to use a roller with multiple thin metal rings in it ...
the idea is to tap a current in the pcb board, then the roller that is attached to a gantry will roll to the pcb (in y axis). Then basically, the current will move from the pcb to the metal rings . We will attach a small connection wires to all the metal rings then the microcontroller will interpret this my determining what wires have voltage, and draws it to the Graphic LCD. With this, the system can determine the copper part of the board and not the plastic/non-conductive part.

Is this possible?
 
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mcgyvr

Joined Oct 15, 2009
5,394
AGAIN... What precision/accuracy do you require?
And what exactly are you using this information for?
 
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Thread Starter

johncena

Joined Aug 15, 2010
32
the precision would be 1~2mm. As i think you can't make two copper/trace lines out of it when applying it on simple circuits... (though i might be wrong)..

Well i think it is a good idea to make a scanner that only detects the copper side of the PCB and then draws it to Graphics LCD, i have never seen one before though, and i think it would be great when used it for CNC pcb drilling machine without the use of PC.
 
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