Category Archives: Uncategorized

Building a Desktop Scanner part 2

drywall-screw-macro

I used an arduino mega, but any micro controller will do.  The mega has the advantage that it can take an inexpensive lcd display shield and still have lots of i/o pins easily accessible.  The arduino can’t safely drive a stepper motor directly so we connect it to a stepper motor driver.  I used an EasyDriver board which is inexpensive and lives up to its name.  The chip at the heart of the EasyDriver needs a heat sink to reach its maximum output, but in this application you probably don’t need one.  You won’t be running it very hard.  I run the arduino, the lcd and the EasyDriver all off a 9V battery.  This power supply somewhat limits the torque that the stepper will produce so if you are planning to turn a large turntable you might need a larger power supply and a heat sink on the driver.

The firmware is pretty simple.  One set of buttons allows you to select the number of exposures to make per revolution. One button starts and stops the scanner.  One button takes a single exposure and then rotates the stepper one increment.  This manual mode is handy with subjects which require each shot to be manually focused.

When I use the scanner I place it on a work table in my shop and mount the camera on a tripod next to it on the floor.  I use a cheap macro rail ($25 on amazon) to help position the camera.  The rail has more flex than is desirable, but it works okay since you aren’t actually touching the camera to trigger the exposure.  I use https://www.thingiverse.com/thing:548006 to hold a sheet of paper as a seamless background.  I also sometimes punch a hole in a sheet of paper and thread it on the stepper shaft to mask out the motor.  This approach might work well for you guys because you can cheaply replace the background if anything drips on it.

As you know lighting is critical for photogrammetry.  I use 3-4 JANSJÖ led desk lamps from Ikea to light the subject.  These lamps are very easy to position, and put out a lot of light.  They have small heads which makes it easy to light small subjects.  They are LEDs so they put out very little heat.  You can improvise diffusers with regular paper and tape.  Plus they are $10 each!  I also sometimes use a cheap LED ring light on the camera lens which provides nice diffuse light, but since it is attached to the filter ring of the lens it tends to get in the way with macro shots where the subject is almost touching the lens.

Another approach to lighting is to put the scanner inside a light tent.  This gives you a lot of diffuse even light and a clean background.  They sell small kits for photographing jewelry which are designed to minimize reflections and glare when shooting shiny things, so they might help with your stuff.  Also a circular polarizer filter would be a good thing to have on hand.  It can be helpful reducing glare.

 

Building a desktop 3d scanner part 1

We have talked about many different options for 3d scanning over the years, but we always come back to photogrammetry.  The process involves taking photographs of an object from all angles and then using software to identify and triangulate the location of parts of the object.  After a lot of number crunching you end up with a 3d scan of the object in the photographs.  The quality of the output is entirely dependent on the quality of the set of photos you start with, and that is where the skill comes in.  The software is pretty easy to run and there aren’t that many options on how to process your data.  The big learning curve happens with the camera.  This simple scanner makes it relatively easy to capture high quality photo sets which will produce high quality scans.

The basic setup is simple: An arduino controls a stepper motor and an infrared LED.  Using the multi camera control library from Sebastian Setz  and the IR LED the arduino emulates a wireless remote for almost any DSLR camera.  It fires off an exposure then rotates the stepper motor to the next position and repeats.  The result is an evenly spaced set of photos ready to feed to your photogrammetry software .

screw scan

By automating the movement of the camera you are guaranteed sufficient overlap between the shots and complete coverage.  So you can concentrate on the quality of the exposure.

Properly exposed razor sharp images are critical for photogrammetry so it is worth talking a bit about the basics of photography.  The two most basic exposure adjustments are aperture (also called f-stop) and shutter speed.  No lens can keep the entire image in focus at one time.  There is always a limited depth of field, the range of distances from the camera through which the image is in focus.  Objects closer or farther away than this focal range are blurred.  Blurring introduces noise and errors into photogrammetry so we want the greatest depth of field possible.  On most cameras this comes about f/11.  Lower f-stops have lower depth of field.  Higher f-stops introduce diffraction errors which can be just as bad.  Shutter speed is critical if you are holding the camera in your hand, but in this case it is on a tripod so it is less important.

The drywall screw example here uses a macro lens to fill the frame with the relatively small subject.   Autofocus generally doesn’t work well with macro photography so you will probably need to focus manually.  An object like this drywall screw is predominantly cylindrical so if it is centered on the axis of the stepper it will stay at the same distance from the camera throughout the revolution.  That means you can set the focus and exposure once and it will work for the entire revolution.  Other shapes of object may require you to focus each shot individually.  If you scan a larger object you may be able to use autofocus to keep the images crisp.

Focus tip: Many DSLR cameras allow you to zoom in on the viewfinder preview image which will allow you to focus even more precisely.

Jpeg compression is another source of noise in your images so you will want to shoot at the highest image quality your camera will allow.  You can shoot RAW and develop as uncompressed TIFFs, but for most scans I just use the highest quality JPEG copmression.

MakerFaire 2015 Part 2

DSC_0079

The new printrbot Play: all metal construction and printrbot quality in a smaller package.  The shielded extruder makes it ideal for kids.  For $399 the price can’t be beat.

 

DSC_0080

Printrbot Plus: a massive 10″ cube build volume with heated bed.  An amazing value for an all metal machine.

 

DSC_0082

Printrbot goes subtractive!  Their new CNC router features printrbot’s usual formula of amazing engineering quality at ridiculously low prices.

 

DSC_0083

This innovative CNC router from printrbot rolls directly on the spoilboard.  This machine can be set up on saw horses when needed and then stores compactly.

 

DSC_0122

Andy talks with Filippo Moroni of Fonderie Digitali, one of several Italian companies represented in a special section.

 

DSC_0119

From the country that brought us Ferrari comes the Wasp, a beautifully made delta that they claim is the world’s fastest FDM machine.

 

DSC_0120

The Wasp features an odd hybrid Bowden system.  The extruder is hung from the carriages using 3 rubber connectors and attached to the hotend via a short Bowden tube.  This allows the hotend to travel amazingly fast while the extruder sort of bounces along after it, loosely coupled via the Bowden tube.  They get the reduced moving mass of a Bowden with the shorter filament path and quick retraction of a direct extruder.

 

DSC_0130

Andy talks with Sheau-Lan Reed, head of HP’s new Sprout project.

 

DSC_0139

The Sprout combines a touch screen computer with a touch pad, a projector and a 2d/3d scanner all in one slick package.

 

DSC_0136

The longer we talked with the HP crew the more people they pulled in to answer our questions.

 

DSC_0134

Here is a print of the shell they scanned.

 

DSC_0147

The package is sweet, the interface is very slick, but the scans all showed some serious artifacts.  If they can clean this up it would be a must-have machine.

 

DSC_0172

Dennon Oosterman of ReDeTec during a quiet moment of Friday afternoon.  Could this finally be a filament recycler that really works?

 

DSC_0175

The ptototype ReDeTec filament extruder.

 

DSC_0176

These rollers pull the freshly extruded filament to stretch it to precisely the right diameter.  The whole system is close loop controlled.

 

DSC_0098

Here is the machine actually extruding pretty good looking filament from virgin pellets.

 

DSC_0174

The extruder was paired with a nice looking print grinder.  The only thing odd was that it was operated by a hand crank.  I guess you are unlikely to get your hand pulled into the machine if you are cranking it with your other hand.  Still it looked a bit awkward.

 

DSC_0094

On Saturday morning he drew such a crowd we couldn’t get near him.  Could it be the “Free Filament” sign?

 

DSC_0078

Andy talks with Patrick Lie founder of PolyForge, one of the first low cost selective laser sintering printers we have seen.

 

DSC_0079

Polyforge uses inexpensive stock laser cutter parts to fuse plastic powder.

 

DSC_0083

The results aren’t yet equal to what can be achieved with other, cheaper technologies, but it is a great start.  Now that the key patents have started to expire we look forward to a large open source community taking on this technology and bringing SLS to the masses.

 

DSC_0026

Andy interviews Hans from Cubicity, bringing quality European filaments to American market.

 

DSC_0044

Boris from Open Electronics talking to Andy about his Chocolate printer.

 

DSC_0040

 

The heated syringe  extruder was printing nicely at the show.

DSC_0041

An optional heated stand keeps two more syringes perfectly heated and ready to swap in for continuous chocolate printing.

 

DSC_0043

This mask was their coolest print, but it was made with regular chocolate that wasn’t tempered properly so the cocoa butter “bloomed” giving it a chalky grey finish.

 

DSC_0038

They switched to a more forgiving coating chocolate and the results were beautiful.  The good news is that the machine is all open source.  The bad news. . . they weren’t giving out samples.

 

DSC_0059

Andy talks with Deanne Bell from Future Engineers.  They sponsor contests for students to design 3d printable objects for the space station.  The winner’s designs are actually printed in space.

 

DSC_0069

This multitool won the contest to design a space tool.  The next contest is to design a space container.  Details at http://www.futureengineers.org/

 

DSC_0064

Andy talks with Niki Werkheiser, the NASA project manager in charge of the space manufacturing program.  We got our first look inside the space printer, but no photos allowed.

 

DSC_0068

An overhang printing test similar to test prints made on the space station.  Can you do without support when printing in micro gravity?  We eagerly await the results.

 

DSC_0070

This simple 3d printable igloo like structure may someday be printed on the moon by fusing moon dust using concentrated sunlight.  This sort of technology could be used to build a moon base quickly and cheaply.  It could perhaps be automated to the extent that humans could arrive with their base already mostly built.

 

DSC_0077

We caught up with our old friend Diego Porqueras from Deezmaker in Pasadena.

 

DSC_0076

He still had the only printer at the show that you could drive around while it prints.  He has flown it on a quadcopter while printing as well.

 

DSC_0116

Andy talks with Lucas Dennison and his dad Greg from e-Nable.

 

DSC_0117

Before his dad started 3dprinting them Lucas had never had a prosthesis.  E-nable connects people with printers with people who need prosthetics, and provides support and know how.  Conventional prosthetics are extremely expensive and kids like Lucas outgrow them very quickly.  3d printing is a real game changer by bringing the cost within reach of anyone.  Lucas can have different hands for different uses.  He can have a new one whenever he needs it so he will never outgrow it.

 

DSC_0130

Lucas was very comfortable clowning around with his 3dprinted prosthetic hand.

 

DSC_0134

Visit enablingthefuture.org for more information or to volunteer.

Makerfaire 2015 Part 1

DSC_0012

Andy talks with Claudio Donndelinger about the latest from Lulzbot.

DSC_0014

No more Buddaschnozzle!  Lulzbots now feature the improved hexagon hot end.

DSC_0018

Brandon Climson with his proud teacher.  This high school freshman completely customized and upgraded his Robo3d.

DSC_0024

This is Brandon’s tricked out Robo with dual ezstruders and led lighting.

DSC_0027

This is Brandon’s liquid cooled computer.  This is a young man to watch.

DSC_0035

Andrew Boggeri of FSL3D gives Andy the run down on the Phoenix their new super DLP printer.  It overcomes the resolution limitations of conventional DLP by automatically moving the projector to 3 different positions per layer.  By using an industrial UV projector they are able to achieve 5 second layer cycles at triple the standard resolution.


DSC_0043Whitney talking with David Rorex of Made Solid.  The only company out there making both resin and filament.

DSC_0021

Made Solid was showing off a Gigabot.  This beast makes my huge printer look small.  Look at the drill bit to the left of the machine.

DSC_0023

Now look at Andy holding the same drill bit print.  Look at the size of that thing.

DSC_0024

Shhhhh!  Top Secret.

DSC_0047Andy talks with Frank Peng of XYZPrinting.

DSC_0049XYZPrinting breaks through the price floor with their new $1500 laser SLA machine.

DSC_0052The first prints look great.


DSC_0065

Patrick Degrendele, CEO of Velleman, a large electronic kit manufacturer now making forays into 3dprinting.

DSC_0060

The Velleman K8200 is sturdy and precisely made of aluminum extrusions.  It features an unusual design where the bed moves in both X and Y and the extruder moves only in the Z axis.  This makes it easy to add all kinds of different print heads.  Next week we look at one modded to print Chocolate!

DSC_0073Andy talks with Ford Fraker of Formlabs.

DSC_0068Formlabs is amazing as always

DSC_0078Their silicone coated tilt vat seems to do the trick nicely.

DSC_0097

 

Andy chats with Fred Kahl aka The Great Fredini.  Fred is a pioneer of 3d portraiture.

DSC_0096

 

This is Fredini’s home built kinect based full body turntable scanner.  He ran a scanning booth at Coney island for several years.

DSC_0109

 

Aaron Jennings from polymaker describes their product line of unique filaments.

DSC_0111

PolyMax, the PLA that’s stronger than ABS.  This stuff is tough!  I bent this sample back and forth like this and I couldn’t break it.  It’s not cheap, but its practically indestructible.

DSC_0156

Brook Drumm, the proud daddy of printrbot, always has a smile when he’s describing his new creations.

 

 

 

 

 

 

 

 

 

 

 

 

DSC_0129A few of my big prints on display at Chimera Art’s booth.

We will see you all next week for the rest of our report from Makerfaire 2015