3D Printering: Blender Tips For Printable Objects

November 14, 2018 by 20 Comments

3D models drawn in Blender work great in a computer animated virtual world but don’t always when brought into a slicer for 3D printing. Slicers require something which makes sense in the real world. And the real world is far less forgiving, as I’ve found out with my own projects which use 3D printed parts.

Our [Brian Benchoff] already talked about making parts in Blender with his two-part series (here and here) so consider this the next step. These are the techniques I’ve come up with for preparing parts for 3D printing before handing them off to a slicer program. Note that the same may apply to other mesh-type modeling programs too, but as Blender is the only one I’ve used, please share your experiences with other programs in the comments below.

I’ll be using the latest version of Blender at this time, version 2.79b. My printer is the Crealty CR-10 and my slicer is Cura 3.1.0. Some of these steps may vary depending on your slicer or if you’re using a printing service. For example, Shapeways has instructions for people creating STLs from Blender for uploading to them.

Continue reading “3D Printering: Blender Tips For Printable Objects” →

Friday Hack Chat: All About Crypto

November 14, 2018 by 15 Comments

What is crypto? Crypto means ‘hidden’, and it’s meant ‘hidden’ since before the Greek alphabet was written, but don’t let that stop you from arguing. For this week’s Hack Chat, we’re going to be talking all about cryptography, a medium of exchange for secrets. If you need confidentiality, integrity, or authenticity, you need cryptography.

Our guest for this week’s Hack Chat will be none other than Nick Sayer. Nick is a frequent attendee of the Hackaday meetups and he’s been building gadgets and gizmos and selling them on Tindie for years now. He’s given talks on design for manufacturing. This year, he designed and developed the Orthrus, an appliance that creates a cryptographically secured USB volume from two microSD cards. Basically, it’s like the Captain Planet team, only instead of rings, you need all the SD cards, and instead of Captain Planet, you summon your data.

For this week’s Hack Chat, we’re going to sit down with and talk about all things cryptography, including understanding what you need, what you don’t, and picking the correct tools. Items of interest will include:

  • When cryptography is needed
  • Cryptography tools
  • The best practices for cryptography

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Cryptography Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Friday, November 16th, at noon, Pacific time. If time zones got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

The Value Of Cardboard In Product Design

November 14, 2018 by 23 Comments

A while ago, [Eric Strebel] created a backpack hanger. The result was great — by just bolting this backpack hanger to the wall, he kept his backpack off the floor and out of the way. There was even a place for him to set his phone to charge. [Eric] is thinking about turning this idea into a product, and just posted a video on his process of making a cardboard mockup.

Since this is a study in industrial design, any mockup will need to keep in mind how the finished article will be constructed. In this case, [Eric] is going to use 4-5mm thick aluminum, cut on a water jet, bent into place, and finally anodized. The finished product will be made out of bent sheet aluminum, so this little bit of product design will use Matboard — a thick, heavy cardboard often used for mounting pictures in frames. The Matboard will substitute for the aluminum, as it is carefully cut, bent, and glued into shape.

The tools for this build are simple, just a hobby knife, razor blade, ruler, and a pen. But there are a few tricks to working with Matboard. To bend these pieces perfectly, [Eric] is painting one side with water. This loosens the fibers in the Matboard, allowing for perfect creases before one layer of the build is glued together.

Once a few layers of this Matboard are glued together, the finished product becomes less like cardboard and more like a very soft wood. This allows [Eric] to use belt sanders and countersink drill bits to give a little bit of polish to this one-off prototype. This finished article works great, and now [Eric] is looking at taking this idea into production.

Continue reading “The Value Of Cardboard In Product Design” →

Hack My House: Opening Raspberry Pi To The Internet, But Not The Whole World

November 14, 2018 by 29 Comments

If you’ve followed along with our series so far, you know we’ve set up a network of Raspberry Pis that PXE boot off a central server, and then used Zoneminder to run a network of IP cameras. Now that some useful services are running in our smart house, how do we access those services when away from home, and how do we keep the rest of the world from spying on our cameras?

Before we get to VPNs and port forwarding, there is a more fundamental issue: Do you trust your devices? What exactly is the firmware on those cheap cameras really doing? You could use Wireshark and a smart switch with port mirroring to audit the camera’s traffic. How much traffic would you need to inspect to feel confident the camera never sends your data off somewhere else?

Thankfully, there’s a better way. One of the major features of surveillance software like Zoneminder is that it aggregates the feeds from the cameras. This process also has the effect of proxying the video feeds: We don’t connect directly to the cameras in order to view them, we connect to the surveillance software. If you don’t completely trust those cameras, then don’t give them internet access. You can make the cameras a physically separate network, only connected to the surveillance machine, or just set their IP addresses manually, and don’t fill in the default route or DNS. Whichever way you set it up, the goal is the same: let your surveillance software talk to the cameras, but don’t let the cameras talk to the outside world.

Edit: As has been pointed out in the comments, leaving off a default route is significantly less effective than separate networks. A truly malicious peice of hardware could easily probe for the gateway.

This idea applies to more than cameras. Any device that doesn’t need internet access to function, can be isolated in this way. While this could be considered paranoia, I consider it simple good practice. Join me after the break to discuss port forwarding vs. VPNs.

Continue reading “Hack My House: Opening Raspberry Pi To The Internet, But Not The Whole World” →

Memory Mapping Methods In The Super Nintendo

November 14, 2018 by 6 Comments

Not only is the Super Nintendo an all-around great platform, both during its prime in the 90s and now during the nostalgia craze, but its relative simplicity compared to modern systems makes it a lot more accessible from a computer science point-of-view. That means that we can get some in-depth discussion on how the Super Nintendo actually does what it does, and understand most of it, like this video from [Retro Game Mechanics Explained] which goes into an incredible amount of detail on the mechanics of the SNES’s memory system.

Two of the interesting memory systems the SNES uses are called DMA and HDMA. DMA stands for direct memory access, and is a way for the Super Nintendo to access memory independently of the CPU. The advantages to this are that it’s incredibly fast compared to more typical methods of accessing memory. This isn’t particulalry unique, but the HDMA system is. It allows the SNES to do all kinds of interesting tricks with its video output display like changing color gradients and doing all kinds of masking effects.

If you’re interested in the inner workings of classic consoles like the SNES, this video gets way down in the weeds in the system itself. It’s interesting to see how programmers were able to squeeze more capability from these limited (by modern standards) systems by manipulating memory like the DMA and HDMA systems do.  [Retro Game Mechanics Explained] is a great resource for exploring in-depth aspects of lots of classic games, like how speedrunners can execute arbitrary code in old Mario games.

Continue reading “Memory Mapping Methods In The Super Nintendo” →

Backyard Planetarium With Magnets

November 14, 2018 by 9 Comments

If you are a Hackaday reader, you probably like space in real life, fiction, or both. A trip to a planetarium is a great treat, but what if you could have a planetarium in your backyard? [Ecasill] thought so and used a Zip Tie domes kit to create just such a thing. It takes some sewing and a projector, but there’s a problem. The dome needs to come down if there is going to be bad weather. The answer? Magnetic dowel rods.

Because the magnets are brittle, plastic dip covers them after epoxy sticks them in place. The cloth has steel bolts to adhere, too. All in, the setup cost about $2,000. That includes a projector, a mirror ball, a sound system, and all the construction.

Continue reading “Backyard Planetarium With Magnets” →

Hackaday Meetup At Electronica: Thursday

November 13, 2018 by 10 Comments

Hackaday’s parent company Supplyframe is at Electronica in Munich this week — booth C5-223. On Thursday from 16:00 – 18:00, they’ll be hosting a Hackaday Happy Hour, with a beer and coffee bar, for everyone in the Hackaday community. They’d love to see you and hear what you’re working on, be it for your day job or your night job.

If you missed the #badgelife exhibit at Supercon, it’s here at Electronica. There will also be some of those mysterious cubes you may have heard about. Richard Hogben and Bogdan Rosu will be DJing fresh beats. Stop by and say hi to [Sophi Kravitz], [Majenta Strongheart], [Alek Bradic], and everyone else from the Supplyframe team.

Hackaday’s own [Elliot Williams] will also be wandering around Electronica Wednesday afternoon. He can’t promise free beer, but if you want to crawl around Electronica with [Elliot], meet up at the Supplyframe booth at 14:30 on Wednesday.