| Author |
Message |
|
|
 Posted: Feb 22, 2012 - 02:28 AM |
|
Joined: May 03, 2011
Posts: 169
Location: Sri Lanka
|
|
| I'm not familiar with CCD and image processing, i take image processing as my last option. |
_________________
~ Chandana ~
a self learner
|
| |
|
|
|
|
|
|
Posted: Feb 22, 2012 - 03:53 AM |
|
Joined: Feb 20, 2012
Posts: 3
Location: SLC, UT, USA
|
|
First off... I'm curious what the rest of the industry does to measure their products and what kind of tolerances they work to. I don't know the mattress industry, but along with others here I have a hard time believing that any of the major mattress manufacturers try to build to within 1mm of the final dimensions.
That said... what about using rails or rollers to square the mattress up on the conveyor before measuring it? That would be simple to rig up. In fact, if they were spring loaded or pneumatic so that they snugged up to the mattress they could even have provisions for taking the measurements.
Being the obsessive compulsive type, I was curious what the industry does about tolerances and measuring. I found the following quote on several sites relating to Simmons mattresses:
Quote:
Like all other bedding manufacturers, Simmons subscribes to the International Sleep Products Association standard for bedding products. Dimension sizes are allowed ± ½" tolerance. If a "bunkie" foundation is used, it shall have the same width, length and tolerances as the finished twin size box spring. Finished sizes are measured from seam to seam on the binding tape at the centerlines of the width and length.
I get the impression this only refers to the length and width and is for the purposes of fitting sheets and frames rather than calculating volume. |
|
|
| |
|
|
|
|
|
|
Posted: Feb 22, 2012 - 08:21 AM |
|
Joined: Dec 01, 2003
Posts: 2502
|
|
A single camera mounted above might not have enough pixels for the desired resolution, but a pair of cameras mounted above and a known distance apart could sure do it.
Also, one could consider laser scanners such as made by Keyence Corp. |
_________________
Tom Pappano
Tulsa, Oklahoma
|
| |
|
|
|
|
|
|
Posted: Feb 22, 2012 - 01:10 PM |
|
Joined: Dec 30, 2004
Posts: 8732
Location: Melbourne,Australia
|
|
| Bosch have some economical laser distance measuring devices with serial output. These have mm resolution. |
|
|
| |
|
|
|
|
|
|
Posted: Feb 22, 2012 - 01:18 PM |
|
Joined: Mar 27, 2002
Posts: 18531
Location: Lund, Sweden
|
|
Let the matress come to stop at the end of the conveyor.
Use a moving photo detector running along the mattress, driven by a stepper motor and either a wire-wheel or a threaded-rod arrangement, to determine the length. A similar arrangement but running across determines the width.
Start outside the mattress. Run until light intensity falls. You are now at one endpoint. Keep running, ounting the number of steps the motor takes, until you see the light again. The measurement is the number of steps times the length of one step. |
|
|
| |
|
|
|
|
|
|
Posted: Feb 22, 2012 - 02:33 PM |
|
Joined: May 03, 2011
Posts: 169
Location: Sri Lanka
|
|
|
Quote:
Use a moving photo detector running along the mattress
mattress it not parallel to bed. |
_________________
~ Chandana ~
a self learner
|
| |
|
|
|
|
|
|
Posted: Feb 22, 2012 - 02:50 PM |
|
Joined: Dec 11, 2007
Posts: 6843
Location: Cleveland, OH
|
|
You were given several options, some which require the mattress to be squared up, (parallel to the wall), for measurement, and at least one method which doesn't care what the orientation of the mattress is.
Both have trade offs, your choice.
If you don't like either of those options, then you have another one to consider:
Put the mattress in a large plastic bag, (which you probably do for storage and shipping anyway), and submerge it in a tank of water.
Measure how high the water mark moves up the side of the tank, which tells you how much water was displaced, which tells you the volume of the mattress.
As you have already weighed the mattress, you can now calculate its density.
This method, by the way, totally eliminates all of the "where, exactly, does the edge of a mattress begin?" issues.
JC |
|
|
| |
|
|
|
|
|
|
Posted: Feb 24, 2012 - 01:50 AM |
|
Joined: May 28, 2006
Posts: 716
Location: Toronto, Canada
|
|
I would install a row of light sensors each millimeter right under the path the mattress passes perpendicular to the direction. Put a laser (or two) on the ceiling that output a line (not a point) and which points to the sensors. Watch out when the mattress start to shadow the sensors and monitor the movement with a rotary encoder. Take many readings and do the math. Same you can do for the height - put the sensors on the wall.
No camera, and it is doable with AVR. You even can push the mattress by hand, no need for motor.
Personally I would use a small notebook to process the data or a tablet. All what the avr has to do is to scan many digital inputs (lets say 1000 times per second),read the encoder and to send serially to PC. One sensor could be one bit in a byte. If you can afford to read through an ADC, you can increase the resolution through interpolation.
If the mattress has to be fixed, then install the laser and sensors in a mobile device as in your scanner.
George. |
_________________
www.sofgel.ro bootloader for mega and xmega
www.elsofgel.com XME development board
|
| |
|
|
|
|
|
FAQ
Search
Register
Log in to check your private messages
Log in
Maximize
RSS
