PlanetCNC

May 25, 2013

anderswallin.net

Länsirastit, Kaitakorpi

2013_05_23_kaitakorpi

Very long #2->#3 and #4->5 legs on this course. No major mistakes but not that fast going either..

by admin at May 25, 2013 07:29 AM

May 24, 2013

RepRap

Like a glue gun on a robot arm...

We've always described the RepRap in simplistic terms as being like a glue gun on a robot arm. Well, someone has taken this rather literally. It's actually quite invigorating to see people attempting to make more challenging structures than stacks of 2D planar laminations, and we've seen people using repraps to do this before, but the Mataerial people seem to have it worked out pretty well.


by noreply@blogger.com (Vik Olliver) at May 24, 2013 11:24 PM

Freesteel

The Queue of Queues Fallacy

Believe it or not, I’ve been working on the Adaptive Clearing strategy recently, attempting to upgrade it to have multi-core capabilities. As you know, the free lunch was declared over 2005 when CPU clock-cycles stopped increasing exponentially. Now, instead, the numbers of cores are increasing. I have 8 cores on my current laptop, and when [...]

by Julian at May 24, 2013 04:56 PM

May 22, 2013

anderswallin.net

Orienteering 8-21.5.2013

2013_05_08_ar_reuna
8.5.2013 Reuna.
#4 veered off course and came close to #9. Should have taken the route shown as the blue line.
#5 too high up the hill close to the control
#12 running along the highest point of the hill would probably have been better

2013_05_14_fl_salmi
14.5.2013 Firmaliiga, Salmi
#1 when initially lost, should have continued to the road, re-located on map, and would have found control much quicker.
#6 approaching the control from above would have been better.

2013_05_21_firmaliiga_laakso
21.5.2013 Firmaliiga, Laakso
#6 the organizers had placed this control incorrectly - more than half of the field did not find it.
#9 only major orienteering mistake here - looking for the control on the wrong hill for about 3 minutes before re-locating using the road.
#12 someone had stolen the control flag! By itself the small EMIT-control taped to a tree was hard to find.
#13 should have approached control from above, not below.

by admin at May 22, 2013 03:42 PM

May 20, 2013

Emergent Properties of Meat

tardiff: diff two (compressed) tar files without extracting

Recently I was googling for a script to compare tar files, and found references to a perl script (which I did not read) which reportedly did this by expanding both tar files and then diffing the trees. This would actually have been fine for my case, but some people noted that their use case involved tarfiles that were too big to extract comfortably. I assume that this is due to space considerations, but doubtless there are time considerations too.

May 20, 2013 09:37 PM

May 16, 2013

lazzzor.soup.io (MetaLab)

[kallaballa] Hab mir wieder einmal eine Nacht im @metalab um die Ohren geschlagen und dies...

1326_11ba_400

Hab mir wieder einmal eine Nacht im @metalab um die Ohren geschlagen und diesmal eine 65x30cm große Wandlampe für Imperielle Discozwecke gemacht...

[Reposted from unique-entity]

May 16, 2013 11:00 AM

May 12, 2013

RepRap

3D Printing Where It Needs To Be






Here is a remarkable achievement  Follow this link for details.

To quote Vik Olliver: "3D Printing Where It Needs To Be."

If the thousands of people involved in RepRap each contributed a few dollars, or twenty minutes of their expertise, think what this would become...

by noreply@blogger.com (Adrian Bowyer) at May 12, 2013 11:54 PM

May 10, 2013

anderswallin.net

Equatorial Wedge - Drawings

By popular demand, drawings for the iOptron MiniTower Equatorial Wedge project I completed in 2010 August-September (see old blog posts: base, top, side, knobs)

Here's how the wedge looks like. It consists of a fixed plate that attaches to the tripod, two fixed side plates that bolt to the bottom plate, and a moving plate that tilts about 10 degrees. The wedge is designed so that the centre of gravity of the MiniTower is positioned straight over the middle of the tripod.

The extra 6mm hole in the side-plates is for an M6 threaded rod through the mount which should provide precise azimuth-adjustment. I did not complete this feature (for example a rotating nut in the fixed plate would be needed).

minitower_wedge

PDF drawings:

by admin at May 10, 2013 09:26 AM

May 09, 2013

Emergent Properties of Meat

I hope my kfreebsd box is still bootable...

Preserving the upgrade messages for posterity, will try rebooting it later...

Setting up grub-pc (1.99-27+deb7u1) ...
(pass0:ahcich0:0:0:0): READ CAPACITY(10). CDB: 25 0 0 0 0 0 0 0 0 0 
(pass0:ahcich0:0:0:0): CAM status: CCB request was invalid
(pass1:ahcich1:0:0:0): READ CAPACITY(10). CDB: 25 0 0 0 0 0 0 0 0 0 
(pass1:ahcich1:0:0:0): CAM status: CCB request was invalid
(pass2:ahcich2:0:0:0): READ CAPACITY(10). CDB: 25 0 0 0 0 0 0 0 0 0 
(pass2:ahcich2:0:0:0): CAM status: CCB request was invalid
(pass3:ahcich3:0:0:0): READ CAPACITY(10). CDB: 25 0 0 0 0 0 0 0 0 0 
(pass3:ahcich3:0:0:0): CAM status: CCB request was invalid
(pass4:ahcich4:0:0:0): READ CAPACITY(10). CDB: 25 0 0 0 0 0 0 0 0 0 
(pass4:ahcich4:0:0:0): CAM status: CCB request was invalid
camcontrol: cam_lookup_pass: CAMGETPASSTHRU ioctl failed
cam_lookup_pass: No such file or directory
cam_lookup_pass: either the pass driver isn't in your kernel
cam_lookup_pass: or ada0p1 doesn't exist
camcontrol: cam_lookup_pass: CAMGETPASSTHRU ioctl failed
cam_lookup_pass: No such file or directory
cam_lookup_pass: either the pass driver isn't in your kernel
cam_lookup_pass: or ada0p1 doesn't exist
Generating grub.cfg ...
Found background image: /usr/share/images/desktop-base/desktop-grub.png
Found kernel of FreeBSD: /boot/kfreebsd-9.0-2-amd64.gz
Found kernel module directory: /lib/modules/9.0-2-amd64
done

Related?

May 09, 2013 06:43 PM

May 08, 2013

anderswallin.net

Orienteering 1-6.5.2013

Some orienteering maps I haven't had time to post before now.

2013_05_01_myrbacka
1.5.2013 Myrbacka. Overall very good orienteering on a fairly easy course.
#3 lost a few seconds looking for the control at a big stone when in fact it was a hill
#9 should have found a quicker/better route on top of the hill at #5
#11 slow out of #10 since I did not find the path immediately

2013_05_02_olars
2.5.2013 Olars. Again quite good! Maybe slightly harder course.
#1 maybe a bit too careful at the start
#3 very slow close to the control - went for the wrong feature inside the control-circle
#7 did not have very good control/feel for the distance along the #6-#7 path. should have kept up speed better along the path.
#10 amazingly, the huge detour right around the hill resulted in the best leg on this course! Fast running on the road/path, then very carefully into the control which looked hard to find on the map.

2013_05_04_salmenkallio
4.5.2013 Salmenkallio. Ugh - many mistakes (five out of twelve legs) - and they were out of maps so had to use a hand-drawn map.
#3 circling around as I was looking for the control on top of a ridge or at a saddle, when in fact it was much lower down. Wrong interpretation of height contours..
#5 BIG problems. It should have been easy to run along the path and look for the right cliff features on the right and find the control 50m from the path. I managed to climb the hill much too soon and circle around on top of it. Dead last in the split-times! :)
#6 veering off compass course to the right, which resulted in unnecessary distance. Blue line shows a better direction.
#11 somehow I was afraid of the green area and decided to run around it, but made a much bigger loop than necessary. Should have run right through(blue line) the green thick area!

2013_05_06_pirttibacka
6.5.2013, Pirttibacka. This should have been a familiar map... but made bigger mistakes on three out of twelve legs. (numbers refer to the control-codes on the map)
#30 Aaargh! How is it possible to start towards the first control at 90-degrees to the right direction??
#6 wanted to run along the path and find the less steep opening in the hill (blue-line). Didn't run far enough and instead circled around #19
#14 my route is direct but the second half is slow going through an area with many details. The blue line probably shows a route which is easier and more fool-proof to implement.

by admin at May 08, 2013 07:02 PM

MetaRepRap Soup

April 30, 2013

anderswallin.net

Crimp Clamp Tool

I've been cranking out parts for this Crimp-Clamp-Tool over the past few days:
(design inspired by Lindsay Wilson's site, which has more information on the seal-off technique)

crimp_clamp

It's used to permanently seal vacuum-systems that are pumped through a ~10 mm diameter copper tube. The jaws of the tool compress the tube and "cold-weld" the tube walls together which seals the tube.

13040021

The top and bottom clamps are milled from 20x40 mm steel bar. The bottom clamp has slots that secure two M12x100 bolts in place, and 6mm holes for M6 screws that hold half inch Thorlabs rods that guide the top and bottom clamps. The top clamp has 12mm holes for the bolts, and half inch holes that I opened up with a boring head so the Thorlabs rods (about 12.66 mm diameter) fit accurately.
13040014

The jaws are 3.125 mm diameter carbide rods (the shaft from old used PCB milling bits). They are held in a V-groove on a rod-holder part that bolts to the top/bottom clamps with M5 screws. I glued the rods to the V-groove with Loctite Hysol.

13040015

Here's how the crimped tubes look like. The first test resulted in a jagged edge, while the second test produced a nice straight cut. We will test how vacuum-tight these are with a Helium sniffer later.

13040022

PDF drawings:

by admin at April 30, 2013 02:31 PM

Iltarastit, Luk

#15-#16 a long pause to read the map on top of the first hill
#16-#17 a small correction to the south just before the control
#18 had a reasonable plan and executed it OK.
#19 again a long pause to read the map
#20 found the swamp instead of the lake :(   didn't have a good plan when leaving #19
#21 again poor planning running up/down hills instead of around them.

2013_04_29_luk

by admin at April 30, 2013 10:17 AM

April 28, 2013

MetaRepRap Soup

[unique-entity] LockholderPrevents your u-lock from being stolen while you are riding.

1893_a555_400

Lockholder

Prevents your u-lock from being stolen while you are riding.
Designed and Printed by Marcel @Metalab

http://www.thingiverse.com/thing:81063

[Reposted from unique-entity]

April 28, 2013 04:54 PM

anderswallin.net

Itärastit, Nybondas, Nordsjö

Out of 12 controls I did OK on five: #1, #5,#6,#7 and #11. All of the rest were a struggle.

Uutela on wikipedia.

2013_04_27_nybondas

by admin at April 28, 2013 07:45 AM

April 24, 2013

RepRap

BotQueue v0.3 - Now with Webcams, Pausing, and More!



Coming quickly on the heels of the last release, the latest v0.3 release of BotQueue adds some really exciting new features that make it much nicer to use.  The coolest new feature is webcam support.  The client can now upload pictures of your machine while it is printing and show it on the BotQueue.com website.  This means you can watch and control your bot from anywhere you have an internet connection using any device you want - computer, laptop, smartphone, or tablet.

Read more about it on the release post or head over to BotQueue.com to try it out.  Works great with RepRap printers.  100% open source guaranteed.

by noreply@blogger.com (Zach Smith) at April 24, 2013 02:42 PM

Emergent Properties of Meat

Dropping Amazon Prime...

Reports are that Amazon has broken Amazon Instant Videos on Linux, Android, and XMBC.

I have no time for this kind of jackassery and have marked my Prime membership to not renew.

Honestly, their "free" video selection was pretty poor anyway, and I rarely watched it, but it was one of the items that made a Prime membership feel like it was worth more to me.

April 24, 2013 02:51 AM

RepRap Builders

CadQuery is OpenSource!

We're pleased to announce that CadQuery is now available under the LGPL license.:  https://github.com/dcowden/cadquery


Enjoy powerful scripting on your own box!

by noreply@blogger.com (Dave) at April 24, 2013 02:04 AM

April 23, 2013

anderswallin.net

Iltarastit, Svedängen

Very straightforward running along roads and paths. Still some snow on the ground which makes direct routes or cutting corners through the woods slow.

2013_04_22_svedangen

by admin at April 23, 2013 05:10 AM

Raumfahrtagentur

Rostock 3D Printer - Test Assembly

This is our first test assembly of the parts of our Rostock 3D/Delta printer:

https://trac.raumfahrtagentur.org/raw-attachment/blog/RostockTest01/IMG_0077.jpg

by fightling at April 23, 2013 01:25 AM

April 20, 2013

anderswallin.net

Itärastit, Degerö

2013_04_20_degero_qr_splits

A fairly easy course with lots of running along roads and paths.
Right at the beginning on #2 I searched for it on the wrong hill - on the wrong side of the road/path ?!?
#3-#4-#5-#6-#7 nothing to report. Running speed is enough for top-10 placings :)
#8 the GPS-path looks ok but speed was slow.
#9 right after #8 the compass seemed to just rotate around and I wasn't confident enough to run by the map alone. Very slow and shaky going to #9.
#10-#11-#12 more fitness required to keep up speed in the forest and uphills
#13 again an easier control and better speed
#14 lost concentration and headed in the wrong direction. Lots of open areas with freshly cut trees (compare to 2012 map)- hard to tell how well the map corresponded to reality here.

by admin at April 20, 2013 07:19 PM

April 18, 2013

anderswallin.net

A White Rabbit test

Update3: Here's what happens if you disconnect the master from the switch. The slave clock runs off on its own, with about 5ppm drift compared to the reference clock. Once the fiber is connected again it takes a few seconds to re-sync and lock on to the master clock.

wr_master_kuitu_irti

Update2: two different measurements, on the left with a short 2m fiber, and on the right with a few hundred meters of fiber to a WR-Switch, and a few hundred meters back.

wr_gm_test_csc_2013apr19

Update: an improved measurement now shows some promise:

wr_gm_test_2013apr19

Testing White Rabbit at work. These are fancy network-cards connected by optical fiber which allow synchronization between the cards at better than 1 nanosecond level. My first results are a bit strange:

wr_grandmaster_short_fiber_slave-pps_stats

This is in "grandmaster" mode where we input a 1 PPS and a 10 MHz signal to one of the cards:

13040007

A second result in "free-running" master mode:

WR_freemaster_pps_stats

 

by admin at April 18, 2013 11:44 AM

April 17, 2013

pycam

Minor fixes and a first approach to testing code

Just in time with the start of spring in northern Germany I happened to take another week of holiday for working on PyCAM again.

I started on Monday with some previously reported issues (handling of special characters and whitespace in the “recent files” list) and some involuntary easter egg process settings that were revealed only ofter some specific activities.

Weiterlesen

by lars at April 17, 2013 11:19 AM

April 15, 2013

anderswallin.net

April 14, 2013

sliptonic

FreeCAD WebGL Export.

This is still early but it's too cool not to share.  Yorik has added a WebGL exporter to the FreeCAD arch module (but it seems to work everywhere in FreeCAD)

Open a model in FreeCAD and select the objects in the tree

Select objects in the tree

 

Export the objcts (File -> Export) and select WebGL


 

 

Save the file and open it in a browser:  WebGL export (will open in a new window)

(The default view is zoomed up close but clicking and dragging with the mouse buttons will zoom/pan/rotate the object.  There's still plenty to be done with materials and lighting but being able to share FreeCAD models through a browser is very cool.)

by Sliptonic at April 14, 2013 04:28 PM

April 13, 2013

Freesteel

World changing at a fast pace

In two entirely different places this week I have seen the world change. With the invention of a new machine tool architecture not based on the floppy cubical structure of all current machine tools that therefore need to be over-engineered to keep them together; and with the witnessing of a hand-held 50kHz distance measuring laser [...]

by Julian at April 13, 2013 10:57 AM

April 08, 2013

anderswallin.net

Iltarastit, Tali

2013_04_08_tali_qr_splits

Still lots of snow on the ground, and a temperature just barely above freezing this evening.

The first red (slow) bit between #19 and #20 could not be avoided - just too much snow for running. A bigger mistake on the #11-#12 leg where clearly the better choice after the bridge would have been to run up the hill. Instead I continued north along the stream looking for the small and steep trail up to the control - which was of course completely covered in snow and invisible. Having not learnt much from this I then sort of repeated the same mistake on #25-#24 where my route is direct, but very slow because of snow up to knee-level or above. A small U-turn on #23-#15, but it probably did not cost much in terms of time lost.

My timing-receipt from the EMIT-system shows strange split-times. We'll see if those are corrected in the final results.

by admin at April 08, 2013 06:51 PM

Emergent Properties of Meat

Just bottled

Based on Austin Homebrew's Apple Peeler recipe kit (2gal wort + 3gal apple juice)

April 08, 2013 02:50 AM

April 05, 2013

anderswallin.net

Strontium Blues

We've been playing with a blue laser at 461 nm in the lab lately. If tuned to just the right frequency (wavelength) neutral Strontium atoms will strongly absorb the laser light. Shortly (5 nanoseconds) after that the atoms emit at 461nm also, allowing us to see them:

strontium_461

The atoms originate from a hot "oven" at the right. It glows dark red because it's heated by driving a 5 A to 7 A current through it. The cloud of absorbing atoms glows at 461nm in the centre of the picture.

We can scan the laser frequency by adjusting the current through the diode-laser that produces the light. If the frequency is too low or too high we'll see nothing as the light will just pass through the cloud of atoms without interacting. On each side of the correct absorption frequency we'll see different parts of the atom cloud light up. This happens because the atoms stream out of the oven in slightly different directions, so they experience a different Doppler shift and will react to light with a wavelength slightly to the blue or red from the centre of the absorption-line at 461nm.

When slowly scanning the laser frequency over the absorption-line we got these nice videos. One with a narrow beam and one where the laser beam was expanded.

These were shot with a Canon DSLR so be sure to view them in HD on youtube!

by admin at April 05, 2013 05:50 PM

April 04, 2013

RepRap

Inside 3D Printing Conference & Expo

The Inside 3D Printing Conference & Expo, April 22-23 in NYC, has attracted 3D printing companies, professionals, industry leaders, and hobbyists who will meet to discuss the latest topics and advancements in the ever-evolving 3D printing field.

You’ll hear presentations by leaders in the field—Avi Reichental, President and CEO of 3D Systems, Hod Lipson, associate professor at Cornell University and coauthor of Fabricated: The World of 3D Printing, and Ofer Shochet, Executive VP of Products at Statasys. View the full agenda here.

Featured Session:

How Professional Investors Are Playing the 3D Printing Boom
A panel of venture capitalists, including professionals from T. Rowe Price Associates, Lux Capital, RRE Ventures, and Piper Jaffray, will explore where investors are placing their bets. You’ll learn what types of startups VCs are interested in funding and where to invest your own money in this emerging industry.

The event’s exhibit hall and networking reception will provide attendants with an exciting opportunity to meet face-to-face with companies in the space.
Reprapers will save 15% off gold passports to the event with the code: RRP15. For the best rates, register today: Thursday, April 4.





by noreply@blogger.com (Adrian Bowyer) at April 04, 2013 08:07 PM

Emergent Properties of Meat

More new hardware: Lenovo Thinkpad T530

My old laptop, a Dell Latitude D830, was just shy of 5 years old, and I decided the time was right to buy a new laptop. So far, so good.

April 04, 2013 12:50 PM

April 02, 2013

anderswallin.net

Current sense circuit

A quick simulation of a current-sense circuit (link via the EEVblog forum)

current_sense_circuit

by admin at April 02, 2013 05:25 PM

Emergent Properties of Meat

GPG Key

I've been spending some time working on Debian stuff, particularly packaging and porting for Debian kFreeBSD. Some time in the future I might wish to become a Debian Maintainer, and a step along the way is to begin using a GPG key.

To that end, here's the fingerprint of my key, which is also uploaded to sks-keyservers.net:

April 02, 2013 02:15 PM

April 01, 2013

anderswallin.net

Sprint orienteering, Ågeli

2013_04_01_ogeli_qr_splits

Orienteering again! All of the snow isn't really gone yet, but the orienteering season kicks in anyway.

This was a 3km easy sprint course where the opportunity for making large errors was quite small. In sprint-O keeping out of the prohibited areas (e.g. back-yards, in green on the map) of the map is a challenge - there are lots of DQs for this in competitions.

I'm not sure how bad going off the map is considered. At the top of the map between #9 and #10 there was an open path where I, and everyone else, ran, but according to the GPS-trace it might be just outside the printed map.

by admin at April 01, 2013 04:24 PM

March 26, 2013

Freesteel

Perpendicular unit vector frame in 3D

Let’s begin with what a unit vector is, and let’s not get sloppy. If we can’t be bothered to do this right, then what does it say about our other more advanced geometric algorithms? I’m a computational geometry programmer, and I don’t like to type, so my 3D point class is defined like so: class [...]

by Julian at March 26, 2013 09:44 PM

March 25, 2013

Raumfahrtagentur

Dress pattern projector

One of the most productive areas at the Raumfahrtagentur is the textile workshop. As we strive to get as close to the bits as possible in our production methods, a longtime goal was to get dress patterns directly from the digital file to the fabric.

A projector at the ceiling with a mirror projects the CAD drawing made in QCad onto the table. That makes it easy to retrace the cutting lines with chalk directly on the fabric.

by frank at March 25, 2013 09:56 PM

March 24, 2013

RepRap

Stop bad 3D printing patents

The EFF and Ask Patents are organising the submission of prior-art to stop 3D printing patents that shouldn't be awarded.  Details are here:

https://www.eff.org/deeplinks/2013/03/effs-fight-open-3d-printing-continues-askpatentscom

There is a vast wealth of research and prior art in the RepRap community, on its Wiki, and in its blogs.  All this material is in the public domain, and any attempt to patent any of it should not, therefore, be allowed.

Please take a minute every now and then to visit the site and see if some company is trying to patent something that you know is already public.  And fill in the form with a reference (or better a link) to any prior art that you know. 


by noreply@blogger.com (Adrian Bowyer) at March 24, 2013 09:04 PM

March 18, 2013

sliptonic

Vendor provided CAD data.

I'm going to build an enclosure for my CNC mill to keep coolant and chips from going all over the floor. It took about ten minutes to model the mill table in FreeCAD but modeling all the aluminum extrusions was looking like a lot of work.  Fortunately it isn't necessary

More and more vendors are providing CAD data in their online catalog.  As long as they provide data in one of the non-proprietary formats, it should import very nicely into FreeCAD.

McMaster-Carr's catalog is legendary and many of their products have CAD data associated.  You can download in a bunch of different formats that are compatible with FreeCAD, HeeksCAD, or probably any other CAD system on the planet.

Just click on the part number . In the item detail pop-up there's a CAD link that will take you to a page where you can get 2D and 3D CAD models and also see some dimension data online.

 

Misumi's site is maybe even better.  Misumi will custom cut aluminum extrusions without a setup fee.  The nice thing is they also provide custom CAD data for the parts you specify.  For example, if you want a 330 mm extrusion, they'll cut it, but you can also download a 330mm model to use in your design.

In the design at the top of the page, I used three different length pieces and played with them in FreeCAD to verify that things would line up on the table the way I wanted.

 

I wish all vendors provided this, along with detailed specs, schematics, and illustrated parts lists.  If you know other noteworthy vendors, drop a comment.

by Sliptonic at March 18, 2013 03:45 PM

March 16, 2013

Emergent Properties of Meat

New thing: BlurBlog

On my front page sidebar, you'll see a new item labeled "BlurBlog". These are links to interesting articles from sites I read and which I resyndicate via the rss reader newsblur. You can click through individual links to visit the original pages, or the "BlurBlog" heading to see larger extracts from the articles and subscribe to the BlurBlog as an rss feed.

March 16, 2013 02:32 PM

March 15, 2013

anderswallin.net

TEC mount for laser-module

tec_adapter_1

tec_adapter_2

I made this aluminium bit on the lathe/mill today. It holds a blue laser-module from dealextreme. The brass barrel measured about 11.81 to 11.84 mm in diameter so I first drilled a 10mm hole, then opened it up slowly on the lathe until the module just fit the hole. There is an M3 set-screw to hold the laser module in place. Four long M2.5 screws clamp the aluminium part into contact with a peltier-element and the copper heatsink. A thermistor for temperature measurement and feedback control will be glued to the aluminium part as close as possible to the peltier.

Temperature control of the laser diode should provide for rough tuning of the laser wavelength. We want the wavelength to be about 405.2 nm, to be used for photoionization of Strontium.

Aside: A few years ago I tried to order some of these 405nm laser-pointers to the university. It was impossibly difficult because the shipments were stopped by the customs. Negotiations with the radiation-safety authorities did not help. It's simply forbidden to import non CE-approved laser-pointers - it doesn't matter if you are a researcher or work at a research institution. The story is completely different for laser modules (this is exactly the same product as the laser-pointer, but without the pen-like shape and the battery holder). Apparently these are classified just as "diodes" or "electronic components" and there are no problems getting them through customs.

by admin at March 15, 2013 04:50 PM

March 10, 2013

RepRap Builders

STEP Mashups..

ParametricParts.com can now do STEP mashups!


A STEP mashup is ModelScript that loads a STEP file, and the applies parametric modifications to the original, producing a new, configurable object even though the original was created in an advanced CAD system.

This example started out as a pulley on thingiverse: the ModelScript modifies the diameter from its original value.


https://parametricparts.com/parts/m6gm8qy6/

We are working on STL import, but truly parametric designs need to have representations more precise than triangluated meshes.  

Enjoy!

by noreply@blogger.com (Dave) at March 10, 2013 05:47 PM

March 07, 2013

RepRap

Monsanto's Bean Counters

Thanks to Melba Kurman for bringing the following writ to the US Supreme Court to my attention:

http://sblog.s3.amazonaws.com/wp-content/uploads/2013/01/WARF-McBride-Amicus-January-24-2013.pdf

As she says, the analogy struck on the bottom of Page 15 is essentially using RepRap as a model for the behaviour of a living system for the purposes of "intellectual property" law.  The wheel has definitely turned full circle...

I wonder, if that argument holds, how far you would get arguing that, as a living thing is deemed to be a type of RepRap machine, then, ipso facto, all living things must fall under the RepRap open licence...

by noreply@blogger.com (Adrian Bowyer) at March 07, 2013 09:14 PM

Raumfahrtagentur

Acetone vapor finishing for 3D printed ABS – getting there...

3D printed parts always have this rough, structured finish where you can see and feel the printed layers very clearly. Various methods have been tried out to get to a nice polished finish. The most promising so far has been treatment with a SMD hot air desoldering station, but thats a lot of manual work and does not always give really nice results.

So a few days ago at  http://blog.reprap.org/2013/02/vapor-treating-abs-rp-parts.html came along an interesting description for using acetone vapor to achieve a nice and smooth surface. Initial trials using a small glass and a minor amount of acetone looked promising, so we ordered some labware and raided the Raumfahrtagentur Biolab for a heatplate with precise temperature control.

Safety warning: acetone and especially acetone vapor is combustive and a fire risk. Only work in a well ventilated place and have a fire extinguisher at hand. Do not heat on an gas stove. Read the safety warnings regarding health risks for acetone. Don´t Panic.

This is our current process description, to be changed and updated as we find out more.

  1. Pour about 2-3mm of acetone into the cylinder
  2. Set it onto the electric heatplate, turn temperature to ca. 110°C

Setup for acetone vapor treatment

  1. Watch as the layer of recondensation of the vapor creeps up on the glass wall. Turn down temperature way before the vapor condensation line raises to the rim of the glass cylinder.

Acetone vapor rising

You can see clearly how high the vapor has risen

  1. Insert your objects. We suspended them on metal wire hanging from the aluminium lid by means of an magnet on the outer side. Not sure if that is the optimum method, but it works for now. It is useful to have a second identical glass cylinder to try out placement of objects and see how high the vapor must rise before the objects are covered.

Objects in acetone vapor

  1. Watch carefully how the objects smooth out, remove when you feel it is enough smoothing. Usually it is just a few minutes. You can see the acetone vapor condensing on the objects that are colder then the vapor as well as on the wires. Maybe one optimization is to pre-heat the objects with a warm air, so less condensation occurs.

Apparently the smoothing continues for a while after removal, until the acetone vapor has vanished. Cover acetone cylinder again and wait a couple of hours for your objects to become hard again.

Update:

First series of controlled experiments with test bodies. 5 minutes is sufficient for proper smoothing. Touch-hard after about 30 minutes sitting. Apparently a little bit of shrinking occurs (less then 0.5mm on 20 mm diameter / width). The test bodies were printed with 3 outer layers and 40% infill, the print was rather sloppy and imperfect. Next series with more infill and / or more outer layers.

OpenScad file with the test bodies attached.

by frank at March 07, 2013 07:18 PM

March 06, 2013

Emergent Properties of Meat

Adventures in localization

When a linuxcnc developer reported testsuite failures, a fellow developer discovered that our tests don't run right in non-English locales—in particular, locales like de_DE where the decimal separator is "," instead of ".". But I'm not here to talk about how to fix the testsuite. Instead, get a load of this behavior inside a bash that was started with LC_ALL=C:
$ printf "%f\n" 1.23
1.230000
$ LC_ALL=de_DE.UTF-8 printf "%f\n" 1.23
1.230000
$ env LC_ALL=de_DE.UTF-8 printf "%f\n" 1.23
1,230000

March 06, 2013 01:59 PM

March 05, 2013

anderswallin.net

Noise equivalent temperature in an RTD/Thermistor

How accurately can you in principle measure temperature with an RTD or thermistor?

If we push a current I through the resistor we'll get a voltage of U=RI across it. Now as the temperature changes the resistance will change by \Delta R = \alpha R \Delta T where \alpha is the temperature coefficient of the sensor. This will give us a signal

\Delta U = I \Delta R = I \alpha R \Delta T


On the other hand the Johnson noise across the resistor will be U_n = \sqrt{4 k_b T R B} where B is the bandwidth, and we get a signal-to-noise ratio of

 \mathrm{SNR} = { I \alpha R \Delta T \over \sqrt{4 k_b T R B} }


The noise-quivalent-temperature (NET) can be defined as  \mathrm{SNR} = 1 or

 \Delta T_{NET}= \sqrt{ {4 k_b T R B \over R^2 I^2 \alpha^2 } }


Here we can identify P=UI=R I^2 as the power dissipated in the resistor and simplify to

 \Delta T_{NET}= \sqrt{ {4 k_b T B \over P \alpha^2 } }

Here's a table with some common values for pt100 and 10k NTC thermistors. The sensitivity \alpha is determined by the sensor type. What limits P is self-heating of the sensor which probably should be kept to a few milli-Kelvins in most precision applications. Thermistors with their higher sensitivity are an obvious choice for high-resolution applications, but the lower \alpha of a pt100 sensor can be compensated with a larger P since most pt100 sensors are physically larger and thus have lower self-heating. pt100 sensors require 4-wire sensing, slightly more complex than a 2-wire measurement which is OK for a thermistor.

Sensor Resistance Sensitivity (divide by R to get alpha!) Dissipated Power P Noise-Equivalent-Temperature
(1Hz bandwidth)
pt100 100 Ohms 0.391 Ohms/C 100 uW (I=1mA) 3 uK
NTC Thermistor 10 kOhms -500 Ohms/C 9 uW (I=30uA) 0.9 uK

I conclude that it is not entirely obvious how to choose between a pt100 and a 10k thermistor. The thermistor is intrinsically more sensitive, but with good thermal contact to its surroundings self-heating in a pt100 sensor can be minimized and the same noise-requivalent-temperature achieved. In any case it looks like Johnson noise limits resolution to 1 uK or so in a 1 Hz bandwidth. If we AD-convert the voltage at 24-bit resolution (16M states) we can get a reasonable measurement range of ~32 K by matching 1 LSB = 2 uK.

Does anyone know of similar back-of-the-envelope calculations for other sensors (Thermocouples, AD590)?

by admin at March 05, 2013 07:23 PM

Measuring the thermal expansion of ULE glass

Here's an experiment I've done recently:


(Time-lapse of ca 18 hour experiment. Bottom left is a spectrum-analyzer view of the beat-note signal. Top left is a frequency counter reading of the beat-note. Bottom right is a screen showing the a camera-view of the output-beam from the resonator)

This is a measurement of the thermal expansion of a fancy optical resonator made from Corning "Ultra Low Expansion" (ULE) glass. This material has a specified thermal expansion of 0.03 ppm/K around room temperature. This thermal expansion is roughly 800-times smaller than Aluminium, around 400-times smaller than Steel, and 40-times better than Invar - a steel grade specifically designed for low thermal expansion.

Can we do even better? Yes! Because ULE glass has a coefficient of thermal expansion (CTE) that crosses zero. Below a certain temperature it shrinks when heated, and above the zero-crossing temperature it expands when heated (like most materials do). This kind of behavior sounds exotic, but is found is something as common as water! (water is heaviest at around 4 C). If we can use the ULE resonator at or very close to this magic zero-crossing temperature it will be very very insensitive to small temperature fluctuations.

So in the experiment I am changing the temperature of the ULE glass and looking for the temperature where the CTE crosses zero (let's call this temperature T_ZCTE). The effect is fairly small: if we are 1 degree C off from T_ZCTE we would expect the 300 mm long piece of ULE glass to be 200 pm (picometers) longer than at T_ZCTE. That's about the size of a single water-molecule, so this length change isn't exactly something you can go and measure with your digital calipers!

Here's how it's done (this drawing is simplified, but shows the essential parts of the experiment):

ule_resonator_drawing

We take a tuneable HeNe laser and lock the frequency of the laser to the ULE-cavity. The optical cavity/resonator is formed between mirrors that are bonded to the ends of the piece of ULE glass. We can lock the laser to one of the modes of the cavity, corresponding to a situation where (twice) the length of the cavity is an integer number of wavelenghts. Now as we change the temperature of the ULE-glass the laser will stay locked, and as the glass shrinks/expands the wavelength (or frequency/color) of the laser will change slightly.

Directly measuring the frequency of laser light isn't possible. Instead we take second HeNe laser, which is stabilized to have a fixed frequency, and detect a beat-note between the stabilized laser and the tuneable laser. The beat-note will have a frequency corresponding to the (absolute value of the) difference in frequency between the two lasers. Now measuring a length-change corresponding to the size of a single water-molecule (200 pm) shouldn't be that hard anymore!

Let's say the stabilized laser has a wavelength of \lambda_1 = 632.8 \,\mathrm{nm} (red light). Its frequency will be \nu_1 = {c \over \lambda_1} =  474083438685209 \,\mathrm{Hz} (that's around 474 THz). When the tuneable laser is locked to the cavity we force its wavelength to agree with \lambda_2 = {2L\over m} where m is an integer and L is the length of the cavity. I've drawn only a small number of wavelengths in the figure, but a realistic integer is m=948167. We get \lambda_2 = 632.7999181579 \,\mathrm{nm} and \nu_2 = {c \over \lambda_2} =   474083500000000 \,\mathrm{Hz}, very nearly but not quite the same wavelength/frequency as the stabilized laser. Now our photodiode which measures the beat-note will measure a frequency of \nu_{beat} = | \nu_1-\nu_2 | = 61.314 \,\mathrm{ MHz}.

How does this change when the ULE glass expands by 200 pm? When we heat or cool the cavity by 1 degree C the length changes to 300 mm + 200 pm, and the wavelength of the tuneable laser will change to
\lambda_3 = 632.7999185797\,\mathrm{nm}. Now our beat-note detector will show \nu_{beat} = | \nu_1-\nu_3 | = 60.998 \,\mathrm{ MHz}. That's a change in the beat-note of more than 300 kHz - easily measurable!

That's how you measure a length-change corresponding to the diameter of a water molecule!

Why do this? Some of the best ultra-stable lasers known are made by locking the laser to this kind of ULE-resonator. Narrow linewidth ultra-stable lasers are interesting for a host of atomic physics and other fundamental physics experiments.

See also: Janis Alnis playing with two ultra-stable lasers.

by admin at March 05, 2013 06:15 PM

March 04, 2013

RepRap

Inside 3D Printing

3D Hackers, Industry experts, venture capitalists, RepRap geeks and people in the engineering, technology, manufacturing, culinary, finance, architecture, medical, and fashion industries will meet at Inside 3D Printing Conference & Expo, April 22-23 in NYC. The two-day event is the first U.S. east coast expo that is fully focused on 3D printing, its applications, and services.

Attendants will hear from notable thought leaders and explore how 3D printing will affect their lives and businesses. The event will feature more than thirty speakers, including people from Solid Concepts Inc, Autodesk, Inc., 3D Systems, Estee Lauder, Stratasys, Authentise, MGX by Materialise, and more.

Keynote presentations will be given by Terry Wohlers, Principal Consultant and President, Wohlers Associates, Inc. (and a sometime critic of aspects of RepRap - go and discuss!) and Peter Weijmarshausen, CEO and Co-Founder of Shapeways.

Featured sessions will include Digital Materials, Spotlight on Fashion, Design Tools in the Age of 3D Printing, Transforming Education Through 3D Printing, Art & Architecture: Redefining the Future of Design, How Professional Investors are Playing the 3D Printing Boom, and 3D Printing Firearms: The End of Gun Control? View the full agenda here.

The conference will also feature an expo hall filled with 3D printing, with companies like 3D Systems and MakerBot to provide opportunities for attendants to talk, to see demonstrations and to make contacts.

Reprapers (that's you!) will get 15% off admission and gold passports with the promo-code: RRP15.  For more information, or to register, click here.

by noreply@blogger.com (Adrian Bowyer) at March 04, 2013 05:55 PM

February 28, 2013

Freesteel

February 27, 2013

RepRap Builders

Introducing Parametric Parts, Productivity for 3D


Content is king, and it's especially true for 3d printing.

That's why I'm proud and excited to introduce Parametric Parts, an alpha product we've been working on that aims to make it easier than ever to create 3d models.

Parametric Parts allows customizing, previewing, downloading, and printing 3d models with your browser. Every model is parametric!

We have an alpha product up and running-- you can give it a try for free with no signup: http://www.parametricparts.com/parts/6m3vp9jd/

We'd love to know what you think!

We're excited because we think this tool will change the way people approach 3d.  We need to stop searching for pre-built models and start making them based on the task at hand.  

2d printers showed up at home when Microsoft Office made it easy to create documents.  And we think 3d printers needs the same thing --  Productivity for 3D.

Make sure to check out the ModelScript tab. If you are a hacker, you'll appreciate the cool, fluent API for creating objects.   The sample is a pillow block with counterbored holes-- outside of definition of user parameters, its implemented in 4 lines of code.  

If you'd like to see lots of samples, check out the Examples

Give it a try! Just go easy on us, its just an alpha!

Let us know what you think! 


by noreply@blogger.com (Dave) at February 27, 2013 12:35 AM

February 26, 2013

RepRap

Vapor Treating ABS RP parts




Treating ABS parts with acetone is almost as old as RepRap itself, but usually this has involved either dipping the part into liquid acetone, which causes white streaks in the parts, or brushing the acetone onto the part with a slurry mix, which can work very well but tends to be a messy process.

I have seen several setups out there, one by the Solidoodle Folks that involved a deep fryer, ice, tubing, and a candy thermometer, or completely passive systems that just used unheated acetone like TBuser of Makerbot did.

Unforgettably I am a horrible mixture of cheap and impatient, so I had to figure out a way to do this for little or no money out of pocket. To do this process you will need your RepRap's Heated Build Plate (must be able to reach 110C), a Glass Jar, Some Aluminum Foil, and a hanger to bend into a hook to get the parts out with.



First place your glass jar on the heated build plate and put a liberal amount of Acetone into the bottom of the jar (3-4mm deep). Initially you need to ramp up to 120C, especially if you have a heavy jar.  As the jar comes up to temp you will see the meniscus from the edge of the vapor cloud slowly creeping up the jar.  Once the vapor is to the top of the jar, turn the plate back down to 90C for the treatment.

Place your sheet of aluminum on your table, and your part on the sheet.  Lower the object into the vapor bath (very carefully, you don't want it falling off).  Leave the object in the acetone until you are happy with the amount of smoothing (the object continues to smooth out over the next few hours).

Once the parts are in process you can not touch them at all, the easiest way we have found to get the parts in and out of the jar is to fold aluminum foil  into a make shift table and use another smaller sheet of aluminum to act as a base for the part.  You can fish the parts out of the jar using a wire coat hanger bent into a make shift flat hook.



When done, carefully remove the object from the bath.  If you're done processing put a lid on the jar loosely and as the vapor cools it will condence back into liquid to be stored in your acetone jar again. Allow the part to sit for another ten minutes, the surface will be very squishy while the residual acetone dries off.

After some concerns were brought up regarding Acetone Vapor on heated surfaces in the home we decided to make the following video for reference:



This was done at Fablocker in NC, USA. By Austin Wilson and Neil Underwood (Spacexula)





by noreply@blogger.com (Neil Underwood) at February 26, 2013 03:55 AM

February 22, 2013

BodgeItQuick Rep Strap Bertha Project

before and after pictures

Work area before importing big box from China !

After unloading the Big box from China unpacking disassembling using video sent from China then after removing the front door and door frame then lifting part by part into the house re-fitting door frame and front door then resembling the machine here is the resulting photos!!

Extra insulation stage 1 and solar power system re-mounting.



Same space just a little bigger machine in the space!





or from the the angle :-


So here is the cutting bed its three times bigger than the original machine!



its had to get good pictures in such close proximity installed and working with 11lts of cooling fluid imagine my supprise at seeing where the water goes in the tube you can see from the picture below.. why I was so supprised.

Yes it is not in the outside of the laser tube but in the inside of the tube its green as it has 25% antifreeze to stop algae growth and improve cooling the laze passes thru the coolant!! it has a 6" extractor tube compared to the 4" of the previous laser cutter all of the works are contained within the case I have added my own extra control circuity for the extractor fan and air compressor as in the original configuration these were on all the time they are now switched on by the controller as and when they are needed thus making this much more energy efficient my next task is to implement another idea buy removing the cooling system and changing it for a ground source cooling eg ground source heating is created from the 8C temperature of the earth 1m down now that could be used equally as well for cooling the tube instead of its radiator cooling system that will only regulate to ambient temperature. I read some place 8C was the optimum temperature to get 50% better cutting efficiency from the tube.

by noreply@blogger.com (BodgeIt) at February 22, 2013 12:53 PM

February 20, 2013

lazzzor.soup.io (MetaLab)

February 19, 2013

Emergent Properties of Meat

Online Anagrammer with AJAX

At the office, we frequently do a scrambled word puzzle from the newspaper. Occasionally I overlook the answer for minutes at a time. In the past I've used various websites or programs to find solutions to these problems, but now I've written my own very fast one from scratch. It includes commandline and web interfaces (including ajax for lightning-fast updates).

You can try it or get the source.

February 19, 2013 10:42 PM

February 17, 2013

lazzzor.soup.io (MetaLab)

February 14, 2013

anderswallin.net

Site of the day on EEWeb.com

EEWeb.com will feature this site as the site-of-the-day tomorrow Thursday! Their circuit simulator at www.partsim.com looks interesting:

PartSim Online Circuit Simulator

by admin at February 14, 2013 12:14 AM

February 12, 2013

anderswallin.net

PD-Amps compared

pd_amp_1 pd_amp_v2

The first design is a single transimpedance-amplifier (TIA) using an ADA4817 and a 1 MOhm resistor. This isn't a great design, since the op-amp is much too fast compared to what is needed/required here. The second design is a 7 kOhm TIA (AD8597) followed by a ~140 V/V gain non-inverting amp (ADA4817). This gives the same total effective gain of ~1 MOhm.

These circuits were designed for a 2 V output with a 2 uA photocurrent produced by about 5 uW of HeNe laser light at 633 nm. The output will hit the "roof" (the positive rail) at about 12 uW of optical power.

The agreement between simulation and experiment is not very good. I suspect my extremely simple LED-test is to blame. I should build a VCSEL circuit which allows testing these and other photodiode receivers to much higher frequencies.

pd_amp_comparison

 

by admin at February 12, 2013 08:01 PM

February 11, 2013

anderswallin.net

PD-Amp v.2 assembled and tested

pd_amp_smd-side_2013feb11 pd_amp_thruhole-side_2013feb11

I assembled and tested the latest photodiode-amp today. I tested the frequency response using a red LED driven directly by an Agilent function-generator with an offset of 1.2 V and a 600 mVpp sine-wave. The LED datasheet doesn't specify a rise-time or bandwidth, but I'm hoping it is fast enough to test this 2-3 MHz receiver. I do have some small VCSELs that should be very fast and suitable for testing photodiode receivers up to 500 MHz and beyond.

The signal from the LED caused a 3 V output swing, which explains the slightly lower observed (large-signal) bandwidth compared to the simulated (small-signal) bandwidth. Some of the difference between the simulated frequency-response and the measured one is probably explained by stray capacitance which slightly lowers the bandwidth.

pd_amp_f-response_2013feb11_withcircuit_x

 

by admin at February 11, 2013 03:31 PM

February 10, 2013

Freesteel

Forces of Production

A tip-off from a Noam Chomsky interview lead me to the book Forces of Production A social history of industrial automation by David F Noble. The core of the book is a history of N/C (Numerical Control) Machining from its development at M.I.T. in the 50′s and the almost total funding of it by the [...]

by Julian at February 10, 2013 04:54 PM

February 08, 2013

anderswallin.net

Photodiode amplifier - version 2

A revised version of the circuit and PCB for a photodiode amplifier, to be used in PDH-locking (Pound-Drever-Hall) as well as RAM-nulling (residual amplitude modulation) in a laser experiment I am doing. The changes compared to the first prototype are:

  • The required bandwidth and gain is not easy to achieve in one stage, so there's a second stage of amplification after the transimpedance amplifier.
  • I'm suspicious of the noise caused by the switched-mode powersupply, as well as the DC2DC converter, of the previous design. So this circuit has just +/-5 V regulators and can be driven from a regular (known good) +/-12 V lab powersupply (or even two 9 V batteries).

Here is a schematic and simulation results produced with the free version of NI Multisim from Analog Devices. The design is for roughly 1 MOhm of transimpedance gain in total, here split between 7 kV/A transimpedance gain, and 144 V/V for the non-inverting second op-amp. At 1 kV/A of transimpedance gain a 5 uW optical signal at 633 nm (HeNe laser!) that produces a 2 uA photocurrent will result in a 2 V output signal. The AC analysis shows very slight gain-peaking for the transimpedance-stage (red trace) and a -3 dB bandwidth of >3 MHz overall (green trace).

pd_amp_2013feb8 pd_amp_2013feb8_ac_sim

The first op-amp used in the transimpedance stage only needs to have a bandwidth slightly exceeding the transimpedance gain bandwidth (the feedback resistor R1 together with the compensating cap C1, the capacitance of the photodiode C2, and the input-capacitance (not shown) of the op-amp form an RC low-pass filter). The AD8597 is marketed as "ultralow distortion/noise" and is fast enough (10 MHz). The second non-inverting op-amp needs a high gain-bandwidth-product (GBP) since we are amplifying ~100-fold here. The ADA4817 has a small-signal bandwidth of 1 GHz and GBP~400 MHz, so should work OK here.

A voltage of only 14 mV over the transimpedance-resistor is not ideal. The Johnson noise (which in principle a good designer can control/minimize) in the resistor will dominate over the shot noise (which we cannot avoid) in the optical signal. For shot-noise limited performance the rule of thumb is to make the voltage drop at least 51 mV (which will make Johnson and shot noise equal). Without tricks however that is not possible as here we have both a weak signal (2 uA of photocurrent), we want a high gain (1 kV/A in total), and we want to go fast (~3 MHz bandwidth)! If you relax any of those requirements (more power, less gain, slower response) it is straightforward to build a shot-noise limited amplifier in one or two stages.

The PCB, fresh from the mill:

pd_amp_pcb_2013feb8

Far right is a 3-pin TO-18 socket for the photodiode. Right-middle are the two op-amps with their feedback-resistors/caps, as well as two de-coupling caps for both +5V and -5V. Left-middle are 7805 and 7905 voltage regulators, and the BNC output-connector is far left. All the surface mount components are mounted on the top layer of the board, while the through-hole components are bottom-mounted. Resistors and caps are 1206-size. This PCB should fit the earlier enclosures I turned on the lathe.

Hopefully I will have time to assemble and test one or two of these next week. I should measure the actual frequency-response and compare it with the simulated one.

by admin at February 08, 2013 09:52 PM

February 06, 2013

Emergent Properties of Meat

The growth of Unicode over time

This graph shows the number of defined code points in unicode from its first release in 1991 to the preset; the last data point is the number of code points in Unicode 6.2 plus all characters from the "pipeline table" of proposed new characters (retrieved January 2013). However, it is likely that only a subset of those characters will be in the next unicode standard.

February 06, 2013 02:59 PM