obligatory obscure reference

Some notes from today’s ride

1. Before you start cycling here, and especially before you move here or look for a place to live, go over to BikePGH and read up on the city. Get their fine cycling map and your riding will go much more smoothly.
2. There’s a popular belief that Pittsburgh drivers are some of the most polite in the US. While this may be true, they also get into dangerous, passive-aggressive games of “no, you first” that block traffic and cause other people to do stupid things.
3. The Pittsburgh Left is as real and as dangerous as it seems.
4. If you see a motorist doing something rude or dangerous don’t assume they’re a jerk. It’s quite likely that they’re probably just incompetent, elderly, or both. The state driver’s exam is a joke — you just drive a bit in a parking lot — and there’s also no mandatory retest as you get older.
5. If elderly, incompetent drivers annoy you then avoid Squirrel Hill.
6. There’s a reason there are sharrows on one side and a bike lane on the other. Trust me.
7. If you’re in Oakland and almost collide with an oblivious college student, thank Pitt.
8. If you’re in the South Side and almost collide with an oblivious hipster, thank PBR.
9. Negley is not nearly as fun as you think it will be.
10. Yes, you broke 35mph without trying. We all have.
11. Cycling here has improved several orders of magnitude in the four years I’ve lived here. There are bike lanes, sharrows, a pro-bike org, and city support for cycling.
12. Tuesday night is Bacon Night at the Harris Grill.

In the middle of dealing with the permit process to build a deck off of our house, I read about the little oopsie Google had with collecting network data while running Street View.

It took me less than one minute to come up with some great ways to “monetize” Google Street View data by selling it to:

• local government code-enforcement units so they can issue fines for building without a permit
• repair/building contractors buying images of “all houses with old gutters” or “all houses with peeling paint”
• law enforcement agencies looking for pot growers (cf. electric bills triggering search warrants)
• security consultants / network security software firms selling fixes for things like unpatched software or open networks

You now have one minute to come up with other ideas, GO!

Building the Makerbot Cupcake was pretty straightforward and it’s been a lot of fun playing with it. My biggest problem right now is the print envelope — 80mmx80mm is all you can realistically hope for, and that’s with a heated platform to control warpage. I’ve made some useful bits for my bike computer project and cranked out a bunch of new year’s ornaments, but other than that I haven’t been using it much. Everything I want to print is too big, either in terms of warpage or in terms of x/y size.

Since I’m interested in bigger things, so I’m looking into building bigger printers. (Anyone who wants to buy me a Stratasys can ask and I’ll give them the delivery address…) One option is to build a Mendel which has an envelope of 200mmx200mm. Another is to figure out how to put a print head on something really big, like a knee mill or a large CNC plasma table.

More platforms back in the store and I dropped the price by $10. Now you have an option of a plate with no peripheral holes as well as an option for the nicrhome kit.

Here’s how I set it up: using Kapton tape, I attached a loop of nichrome wire to the underside of the platform. I also put the thermistor in an “average” spot away from the wire:

This connects using the A6 pin on the extruder, same as other boards, all of which are basically doing what Eberhard documented on his blog. For software, you’ll need to download and build the latest ReplicatorG and firmware from the makerbot github.

[tags]makerbot[/tags]

I do privacy and security stuff for a living, so I can honestly say that Facebook doesn’t have to make everything opt-in by default. They could just as easily do opt-neutral or even opt-out by default, but they’ve decided to err in favor of stalkers and data miners.

Facebook has added a new privacy setting called “Instant Personalization” that shares data with non-Facebook websites BY DEFAULT. You have to manually go and turn it off you don’t want Facebook to share your data with non-Facebook websites.

On top of that, Facebook will still let your friends share information about you on other sites unless you block the individual applications.

You can turn off the data sharing by Facebook within Facebook settings: Account > Privacy Settings > Applications and Websites -> Instant Personalization -> Edit Setting

To block the Applications, you have to go to each and every Application within Facebook and individually block it:

Pandora: http://www.facebook.com/apps/application.php?id=139475280761

Yelp: http://www.facebook.com/apps/application.php?id=97534753161

docs.com: I haven’t found the app yet.

I pretty much agree with the entire daring fireball writeup except for one bit:

Admittedly, it would be very hard to get someone on the phone at Apple who would know what a device such as this one is. Apple, like most large companies, deliberately makes it difficult for consumers to reach (non-retail) employees. There is no lost prototype hotline.

True, there’s no “lost prototype hotline”, but it’s pretty easy to get ahold of Apple. I bet any one of these would have worked just fine:

• Walk into any Apple store and ask the manager how to get a lost prototype back to Cupertino.
• Post to twitter: “Hey Apple, I think I found a lost prototype. How do I return it to Cupertino?”
• Go to Apple’s website, click on the “Contact Us” link, scroll down to “Apple Public Relations”, dial the toll-free number and explain what you found.

It’s not rocket surgery, people.

Today I got an interesting screen on twitter:

Now stop for a second and think about this. Twitter won’t reveal my phone number, but they will let people search for me by my phone number.

So if I just search for all permutations of phone numbers for a given NPA (area code) and NXX (the first three digits of a phone number in the USA), I can make a list of twitter users in a given geographic area or at a specific business. NPA is often a geographically large area, but a given NPA/NXX pair can be very small — as small as a single company or small town.

Obviously you’d get caught trying to search for a bajillion contacts at once, but if I opened ~50 twitter accounts and added 10-20 numbers to each account per day, I could do 500-1000 lookups and cover a given NPA/NXX pair within a week or so.

Before you assemble your extruder, check to see how big the thermistor head is. If it’s around 1mm and not around 3mm, then you might want to use a different set of values in the thermistor lookup table, as the resistance is different at various temperatures.

The reason this matters is that it’s how the Cupcake monitors the temperature of the extruder. You want to be printing ABS at around 220C, but the smaller thermistor will “read low”, so the temperature reported back to the software is off. To get to the right temp, you have to fudge it and set it at 240, then make sure you change it to 240 anywhere in g code generated by software.

It’s easier, in my opinion, to just make/use a new ThermistorTable.cpp:

1. if you have access to a temperature probe that’s good up to around 260C, use the reprap thermistor page as a guide to making your own table.
2. follow the makerbot wiki instructions on upgrading your firmware to verify that the default software will build/install. If anything goes wrong, or this table doesn’t work for you, you need to be able to revert.
3. make a backup of the ThermistorTable.cpp file
4. copy the new table (found below) into ThermistorTable.cpp
5. rebuild and install just like you did with the default software

This is the table I’m using with a 1mm thermistor, I’m able to set the temp to 220C and print quite nicely.

#include "ThermistorTable.h"
// Thermistor
 lookup table for RepRap Temperature Sensor Boards (http://make.rrrf.org/ts)
// Made with createTemperatureLookup.py (http://svn.reprap.org/trunk/reprap/firmware/Arduino/utilities/createTemperatureLookup.py)
// ./createTemperatureLookup.py --r0=93700 --t0=24 --r1=0 --r2=4700 --beta=4881 --max-adc=1023
// r0: 93700
// t0: 24
// r1: 0
// r2: 4700
// beta: 4881
// max adc: 1023
#define NUMTEMPS 20
short temptable[NUMTEMPS][2] = {
   {1, 477},
   {54, 189},
   {107, 159},
   {160, 142},
   {213, 130},
   {266, 120},
   {319, 112},
   {372, 106},
   {425, 99},
   {478, 93},
   {531, 88},
   {584, 82},
   {637, 77},
   {690, 71},
   {743, 65},
   {796, 59},
   {849, 51},
   {902, 43},
   {955, 30},
   {1008, 4}
};

New in the store: a nichrome kit option for heating the Al print platform and international shipping options.

Here’s how I set it up: using Kapton tape, I attached a loop of nichrome wire to the underside of the platform. I also put the thermistor in an “average” spot away from the wire:

The big problem here is that the harness is not attached, so there’s no strain relief for where the wires are soldered to the thermistor and nichrome. Industrial hot glue doesn’t work, so I’m going to give heat-resistant epoxy a try next.

EDIT: Oops, completely forgot about how to hook it up! I’m using the A6 pin on the extruder, basically copying what Eberhard documented on his blog. For software, you’ll need to download and build the latest ReplicatorG and firmware from the makerbot github.

[tags]makerbot[/tags]

Take THREE at writing this up. (Ecto, you are dead to me. It is not
worth my time to ask for a refund, that’s just how dead to me you are.)

If you’re considering a MakerBot Cupcake or other scratchbuilt,
open-source 3D printer for your home, read on. I’ve had one for several
weeks now and this is yet another entry about life with a first-gen,
home-scale 3D printer.

Location

It’s noisy. It smells. It’s like having a
mimeograph in your house. Yes, you can do a lot of useful things with
it and yes, it will generate a number of new and interesting smells and
sounds.

When I first set mine up, I had it on a hardwood floor in my
second-floor studio. While it was printing, I walked down stairs and
discovered it was about as loud downstairs as upstairs thanks to all the
vibrations being transmitted through the floor. I’ve since moved it to
the top of some shelves and will also add a rubber sheet under it to see
how that helps with the noise.

The steppers are noisy. Printing means that at least one, and often two going at the same time. How noisy are steppers? Well, people have performed songs using steppers, that’s how noisy they are.

Finally there’s the lovely smell of melting ABS. The MSDS for ABS isn’t
too terrifying, but I get tired of the smell after awhile. Plan on
having your MakerBot near a source of fresh air or other ventilation.

Oh, and solve all these location issues while keeping it next to the
computer you’re using to drive it, as you’ll be going between the two
quite a bit for the first few weeks.

Tools

There are a few tools that I’ve found handy to keep near the MakerBot. Handy enough that I’m buying “replacements” for where they used to live, because I’m tried of moving them back and
forth.

• dykes or wire cutters: useful for getting a nice clean cut on the ABS filament single-edge
• razor scraper: if you’re using acrylic platforms, this makes it much easier to get the raft off.
• small (~15cm) ruler for adjusting/aligning the Z-axis after you crash the head.

Software

I’m focused on OSX right now, but some of these packages are available on those platforms and may have different issues.

The biggest issue I’m facing on OSX is Intel vs. PowerPC. It seems that the python builds for these two platforms aren’t “bug compatible” across the two different architectures. Skeinforge, the primary tool used by the greater reprap community for converting STL to g code functions differently on the different architectures. My plan had been to dedicate my old PowerPC G5 to running the MakerBot and some scanners, but currently I have to keep my Intel MacBook nearby in order to run skeinforge.

One of the handier tools if you’re using OSX is
Other than that, things have been going fairly well. Blender turns out to be very powerful, but it’s not only non-intuitive, it’s counter-intuitive in places. Do a bunch of the tutorials and get used to the idea that a “unit” in Blender is “1mm” on the printer.

Printing

Almost every problem I had was due to not getting the extruder to the right temperature for ABS. The supplier changed parts on the MakerBot crew and nobody noticed until too late, so some of us got “the tiny thermistor” (about 1mm wide) that reads higher than the normal thermistor people were using. After some fiddling around with a temperature probe, I made a new source file for the build, you can find it on the makerbot group.

Once I nailed the temperature, it was time to do something about alignment/adjustment. I tightened the belts as snug as possible then trammed my build platform (more on that in a future post). The final step will be to go to a heated platform, as this seems to yield large prints that don’t warp.

[tags]makerbot,reprap[/tags]