Makers are serial novices

July 8th, 2016

A maker is a serial novice. I’ve built several robots. Each time I build a new robot, I learn something new–either a new skill, something new about electronics, or something new about programming.

Every project we do as makers has at least one new thing for us to learn. Great projects have more than one thing to learn, as well as using skills we already have.

We should embrace learning–that’s how we grow.

Adding an aluminum band to BB-8

June 25th, 2016

For my BB-8, I’m doing mixed materials. The dome and body are both Styrofoam, with additional materials added as necessary. One of the pieces I’ve added is an aluminum band around the bottom of the dome.

I managed to find a strip of aluminum at Ace Hardware that’s 1/16″ thick, 3/4″x48″. The band only needed to be 37″, so I cut it off with a rotary tool. I needed to get the correct bend, and I wasn’t sure that this particular strip of aluminum would bend okay. I measured and found that the rings on an orange Home Depot bucket are 37″, so I clamped the aluminum to one of the buckets.

Aluminum strip clamped to bucket

This gave it a nice bend, but it didn’t stay at this curvature. Next, I glued it to the dome and clamped it in place while the glue dried.

Aluminum strip clamped to BB-8

I did some spot gluing at the very ends. The result came out nice. I guess I’m ready to start as an apprentice cooper!

Dome with aluminum band

3D printing is one tool

June 20th, 2016

3D printing is only one tool in making. Saying “I only do 3D printing” is like a carpenter saying “I only use a saw”. We use 3D printing for a variety of purposes:

  • Calibrating settings (e.g. layers, infill, print speed, overhangs, rafts, etc.)
  • Test prints (checking sizes and fit, overall look, supports)
  • Internal parts
  • Parts to be combined with other 3D printed parts or with other types of objects
  • Complete pieces

The type of finishing needed varies depending on the purpose. For calibration, finishing would obscure the results. Internal parts might need only to have rafts and supports removed, or possibly some sanding or filing for fit. Visible parts or complete objects should be finished to an appropriate look.

Functions are cheap

June 18th, 2016

As object-oriented programmers (or procedural), we have a tendency to write a lot of code with barely any functions. It’s better to adopt a mindset that functions are cheap. The only time this isn’t true is when you measure the speed of the code and find that functions are slow–typically because you’re calling them millions of times. Other than that, we should be using functions much more than we currently are.

When to use functions

The condition of an if, while, or for is a perfect place to use functions if the condition is complicate. Something like a == b is fine, but a condition like a == b || (c != d && e == f) could be pulled out into a separate function.

The body of an  if, while, or for is another good place to pull code out into a separate function.

Why to use functions

Using functions gives us an opportunity to name a condition or a computation. This helps make the code more readable. For example:

if (condition == CONDITION1 || condition == CONDITION2) { }

or

if (isErrorCondition(condition)) { }

Similarly:

if (objectDetected()) {

motorLeft(BACK);

motorRight(BACK);

wait(100);

motorLeft(STOP);

motorRight(FORWARD);

wait(100);

motorLeft(FORWARD);

}

or

if (objectDetected()) {

robotAvoidObject();

}

Finishing 3D Prints

June 17th, 2016

I’m building a BB-8. My BB-8 is a mixture of Styrofoam, metal, and 3D printed parts.

Here are a couple of the 3D printed parts:

3D printed BB-8 pieces

These pieces printed pretty much the way they’re sitting. On my printer, this left ridges going around parallel to the circles. I finished these pieces by sanding. So much sanding. I spent several hours sanding each piece. I used 220 grit sandpaper. Because these pieces aren’t going to be handled much (they’re going to be attached to BB-8’s dome), I only sanded them until they felt smooth to my fingers. For a different project, I might have continued on with different sandpapers to smooth them out even more. I sanded perpendicular to the ridges (e.g. up and down).

I used standard acrylic paint (black and gray mixed) and painted each one a couple of times, mostly to get the right color. This gives a really good look. I adjusted the colors in the image slightly to bring out the pieces more. They look really good in person.

These pieces are supposed to be some kind of metal or plastic, so I stopped with the painting. I’ll do some weathering on the dome when I’ve finished painting and assembly.

If these pieces had been intended to simulate wood or stone, then I would have textured the surface. For wood, you can simulate grain by cutting lines with an X-acto knife (one direction), and doing some light sanding with a 50 or 100 grit sandpaper, then washing with a dark color. For stone, you can rough the surface up even more with sandpaper, depending on what look or feel you’re going for.

3d printing a Star Wars comlink

January 5th, 2016

I printed out a Star Wars comlink. It came in three pieces: a microphone, a grip, and an endcap. With the initial print, neither the microphone nor the endcap fit the grip. The inside diameters were too small. This may be an artifact of either the printer or the slicing software.

I used netfabb to resize the microphone and cap to be 2mm larger. They fit the grip, but then the outside diameter was larger than the grip, so it doesn’t look right.

I still had the original microphone and cap, so I edited the grip model in Tinkercad using a circular ring, which I turned into a hole a scaled to just remove the outer portion of the connecting rings on the grip. Then I reprinted the grip, and everything fits and is the right size now. I painted the original–I still need to sand down the new one and paint it.

One assembled comlink, one in pieces

Unboxing a Mod-t 3D printer from New Matter

December 5th, 2015

I received a Mod-t 3D printer from New Matter (after a year and a half of waiting, of course it arrived the week I was away on vacation).

The packaging is impressive.

Boxed Mod-t

The box itself has instructions for how to unbox the printer:

Instructions for unboxing the Mod-t

The instructions were simple to follow and resulted in this:

Mod-t ready to go

To set up the printer, you connect it to either a Windows computer or a Mac and download some software. The software sets up the printer’s firmware and helps it connect to wi-fi. Note that you need to be using WPA2. Our router was using WEP, so I had to upgrade it (and enter in new passwords for all of our wireless devices). After changing the router, I tried to connect the printer three times and got a “Failed to connect” message each time, and the printer status said it was disconnected. After the third time, I hit the Refresh button, and the printer was suddenly connected.

Once the printer was connected to wi-fi,  the software wanted to print a test print. The test print is nice–it’s a 3D version of the New Matter logo. The print took a couple of minutes. To remove a print, you take off the build plate, which is a plastic plate that sits on top of the build platform. You can bend and twist the build plate, and the print will pop off. There’s a video at New Matter showing how to remove a print.

Next, I printed two copies of the Maker Faire Robot, which is a robot mascot from the Make 3D printer tests from 2014. The first print came out fine. On the second print, the robot’s arm was forward, like it was shaking hands, and the supports were rotated forward as well. I’m not sure what happened.

Image of completed Maker Faire Robot

The next thing I printed was a space-filling (CPK) model of water. It came out beautifully–essential perfect for a 3D model, which means there are small ridges from the layers, but it is smooth and even. I really like the water molecule print. It came out well, and with the default 25% fill it has a good weight to it. This is going to be a nice print to finish (smooth and paint). I will post a final picture when it’s done.
Model of water molecule

When working on another print, the Mod-t had a calibration error and ended up melting a hole in the build plate. I talked to New Matter customer support, and they were very helpful. They’re sending us a new build plate, and on their suggestion, I sanded out the edge of the hole so it was even with the rest of the build plate and put blue painter’s tape over the hole. It’s working fine. If you’re new to 3D printing, it’s pretty common to put blue painter’s tape on build plates (depending on your 3D printer).

I’ve had one build fail because of a broken filament, and a second print fail because the filament got tangled and failed to feed correctly. That second one was my error–I didn’t feed the filament through the hole in the spool after it broke, so it managed to get free of the spool.

The firmware on the machine is still early–it’s version 0.5.0. New Matter is doing regular updates, and each update improves it.

I’m impressed with the machine–it’s quiet, reliable, and produces nice prints. It has a smaller build volume (6″ x 4″ x 5″ or 150mm x 100mm x 125mm), but I think it’s a good starter machine.

Software for 3D design

October 12th, 2015

There are different types of software you can use to design 3D models for printing.

CAD software

CAD software is good for building useful objects. It is based on building with solid 3D shapes and 3D holes (which are the same as the solid shapes).

  • Tinkercad is a nice online CAD program. You can actually send the 3D models to print directly to Shapeways.
  • SketchUp is a Google program that was originally designed for buildings but can be used for more general 3D models.

Sculpting software

Another way of creating 3D models is by using sculpting software. This type of software is similar to using clay. You can push the starting object in different directions to create a 3D model.

  • 123D Sculpt+ is from AutoDesk. They have a whole series of modeling programs based on the name 123D.
  • Sculptris is another popular sculpting program

Photo reconstruction software

Photo reconstruction software works by taking a series of pictures of a real object and building a 3D model from the pictures. To get good results, you need at least one set of pictures from all angles around the object (maybe 10-20, depending on the software and the object), and then another pass from slightly above, angled down (maybe another 6-10 pictures).

  • 123D Catch is another program from AutoDesk. This is nice because it guides you by showing you which angle you need to take a picture from. When you’re done, you click OK and the pictures will be uploaded, and you will (hopefully) get a model later.
  • Arc3D is a website where you can submit a set of pictures, and it will generate one or more models for you. Unlike 123D Catch, you’re responsible for making sure you have enough pictures from enough angles to cover the model.

Software for cleaning up meshes

After creating a model, sometimes there are problems with printing it directly. In those cases, you need software so you can go and clean it up (remove extraneous bits, close holes, make a flat base, etc.)

  • Meshlab is popular and has a lot of filters and add-ons. There are good video tutorials on how to use different parts of it.
  • Netfabb has fewer options than Meshlab, but is also good at basic cleaning and repairing meshes.

3D Printing Minecraft and World of Warcraft models

September 18th, 2015

Minecraft

Commercial Services

There are commercial services which will take your Minecraft world, extract your model, and 3D print it.

  • Printcraft is a Minecraft server which lets you build models and create an STL from them, which you can then download.
  • WhiteClouds is a commercial service where you upload your Minecraft world and select the coordinates for the model you would like printed.
  • Minetoys allows you to get a custom avatar printed
  • MyCraft is another service allowing custom avatars
  • Figureprints provides a world exporter which you download, then choose part of your Minecraft world and upload it

Add-ons for Minecraft

  • Mineways is a free, open-source program for exporting Minecraft models
  • Minecraft.print() is another add-on for exporting Minecraft models

Importing 3D models to Minecraft

  • You can use Tinkercad to design 3D models, then export to Minecraft by going to Design -> Download for Minecraft

World of Warcraft

Commercial Services

  • Figureprints does very nice 3D prints of your character–either the full character or a bust

Standalone programs

  • WoW Model Viewer can be used to create and build characters and export them to a .OBJ file, which can then be converted to an STL file.

How to finish PLA 3D prints

September 12th, 2015

For all finishing techniques, please be careful and follow the appropriate safety precautions.
Acetone doesn’t work to smooth PLA. However, several people are experimenting with vapor smoothing using different materials (such as MEK substitute) and different techniques.
Sanding works, but it takes longer than for ABS. Basically, start with rougher sandpaper and work to finer, working over the material in small circles. Here’s a good example of sanding. Another specific example, going from 220 grit sandpaper to 600 grit wet sandpaper to #0000 steel wool.
You can try sand-blasting PLA prints. It definitely results in a unique look.

If you need to join two PLA pieces together, then friction welding may be what you’re looking for.