Generate 3D Printable QR Codes With This Web Tool

February 8, 2020 by Tom Nardi 15 Comments

Since most people are carrying a camera-equipped computer in their pockets these days, QR codes can be a great way to easily share short snippets of information. You can put one on your business card so people can quickly access your contact information, or on your living room wall with your network’s SSID and encryption key. The design of QR codes also make them well suited to 3D printing, and thanks to a new web-based tool, you can generate your own custom STL in seconds.

Created by [Felix Stein], the website provides an easy to use interface for the many options possible with QR codes. Obviously you have full control over the actual content of the code, be it a simple URL or a something more specific like a pre-formatted SMS message. But you can also tweak physical parameters like size and thickness.

Once you’re happy with the 3D preview, you can have the website generate an STL for either single or multi-extrusion printers. For those of us who are puttering along with single extruder machines, you’ll need to swap the filament color at the appropriate layer manually. With so many variables involved, you’ll also need figure out which layer the swap should happen on your own.

Incidentally, this is an excellent example of where STL leaves something to be desired. When using a format like 3MF, color and material information could be baked right into the model. Once opened in a sufficiently modern slicer, all the tricky bits would automatically sorted out. Or at least, that’s what Prusa Research is hoping for.

Bar Code Adds A Third Dimension

November 22, 2018 by Al Williams 40 Comments

We never really thought about it before, but a traditional barcode or QR code is pretty two dimensional. A 3D barcode sounds like marketing hype but the JAB (Just Another Barcode) system adds a third dimension in the form of color.

Traditional barcodes assume you have a pretty crude sensor, but a color camera now days is no big deal, so why not take advantage? The JAB system specifies two types of symbols: a master symbol and a slave symbol. A master symbol has four finder patterns at the corner. Slave symbols dock to a master or another docked slave.

If you want to create some JABs, there’s a web interface. If you check advanced, you can change the number of colors used, the size of each “module” (colored box), and the width and height of the master symbol. You can also arrange for error correction. The grid that shows the master and slave symbols will allow you to click on any dockable slave location to create more symbols with different attributes.

You can then save the JAB image and use the scan menu item (at the top) to read the code back. It will also read from a camera.

If you are using a color camera and a computer or phone to read barcodes, this probably is something to check out. After all, you are acquiring color data, why not use it?

You might think of the barcode as something modern, but it has a long strange history going back to the 1930s. Early barcodes looked like bullseyes and were actually inspired by Morse code. We wonder how one of these would look on someone’s arm in ink?

A QR Code, Step By Step

November 5, 2018 by Jenny List 22 Comments

We should all be familiar with QR codes, those blocky printed patterns containing encoded text, URLs, or other data. A few years ago they were subject to their own cloud of hype, but now they have settled down in their niche of providing a handy route for a smartphone owner to reach a website without having to type an address.

Have you ever wondered how they work? There are plenty of dry technical guides out there, but if they’re not your thing you might find [Nayuki]’s step-by-step guide to be of interest. It explains the encoding and error checking bit generation process before starting on the familiar three-squares pattern and timing bars of the QR code itself. The really interesting part comes with its explanation of overlays, a set of repeating patterns that are added to the final data segment, and how the pattern used is chosen to minimise penalties due to large blocks of the same colour in the final piece. The chances are most of us will never have to create a QR code from scratch, but it is this type of fascinating technical general knowledge that makes guides like this such an interesting read.

QR codes have appeared in quite a few projects here over the years, but the one we find particularly amusing is this project to hack them by changing one QR into another.

Via Hacker News.

Improving Indoor Navigation Of Robots With IR

June 27, 2018 by Brian Benchoff 20 Comments

If the booths at CES are to be believed, the future is full of home robots: everything from humanoid robots on wheels to Alexas duct taped to a Roomba. Back in reality, home robots really aren’t a thing yet. There’s an obvious reason for this: getting around a house is hard. A robot might actually need legs to get up and down stairs, and GPS simply doesn’t exist indoors, at least to the accuracy needed. How on Earth does a robot even navigate indoors?

This project for the Hackaday Prize solves the problem of indoor navigation, and it does it in an amazingly clever way. This is using QR codes for navigation, but not just any QR codes. They’re QR codes read by an infrared camera, and painted on the walls and ceilings with a special IR sensitive paint that’s invisible to the human eye. It’s navigation for robotic vision, and it’s a fantastic idea.

The basic idea behind this project is to use an IR camera — or basically any webcam with the IR blocking filter removed — and a massive amount of IR LEDs to illuminate any target. So far, the proof of concept works. A computer can easily read QR codes, and if paint is invisible to the human eye but visible to an IR camera, the entire project is merely a matter of implementation.

There have been a number of projects that try to add indoor navigation to robots. Some of them use LIDAR, some use computer vision and SLAM. These are computationally expensive. Some even use wireless beacons to navigate indoors like the SubPos Ranger from the 2016 Hackaday Prize. Using IR and QR codes is just so simple and hacker-friendly, and we think it’s fantastic.

Eating A QR Code May Save Your Life Someday

February 6, 2018 by Tom Nardi 51 Comments

QR codes are easy to produce, resistant to damage, and can hold a considerable amount of data. But generally speaking, eating them has no practical purpose. Unfortunately the human digestive tract lacks the ability to interpret barcodes, 2D or otherwise. But thanks to the University of Copenhagen, that may soon change.

A new paper featured in the International Journal of Pharmaceutics details research being done to print QR codes with ink that contains medicine. The mixture of medicines in the ink can be tailored to each individual patient, and the QR code itself can contain information about who the drugs were mixed for. With a standard QR reader application on their smartphone, nurses and care givers can scan the medicine itself and know they are giving it to the right person; cutting down the risk of giving patients the wrong medication.

The process involves using a specialized inkjet printer to deposit the medicine-infused ink on a white edible substrate. In testing, the substrate held up to rough handling and harsh conditions while still keeping the QR code legible; an important test if this technology is to make the leap from research laboratory to real-world hospitals.

In the future the researchers hope the edible substrate can be produced and sent to medical centers, and that the medicinal ink itself will be printable on standard inkjet printers. If different medicines were loaded into the printer as different colors, it should even be possible to mix customized drug “cocktails” through software. Like many research projects it seems likely the real-world application of the technology won’t be as easy as the researchers hope, but it’s a fascinating take on the traditional method of dispersing medication.

QR codes have long been a favorite of the hacker community. From recovering data from partial codes to using them to tunnel TCP/IP, we’ve seen our fair share of QR hacks over the years.

[Thanks to Qes for the tip]

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Reconstructing A Blurry QR Code

October 26, 2017 by Lewin Day 4 Comments

QR Codes are a two-dimensional type of matrix barcode that are used for a variety of uses. They’re one way of turning a long piece of string data into an easily machine-readable format. For this reason, they can be used to store private keys for encryption and crypto-currency purposes. [Roger Ver] attempted to use a QR code containing a private key to give away some cryptocurrency on TV, but the code was blurred out by the broadcaster. Not ones to give up easily, [Michael] and [Clément] decided to see if they could reconstruct it anyway.

The work begins, as so many cryptographic exploits do, with the collection of as much of the plaintext key as possible. By stepping through the footage frame by frame, small pieces of the unobscured QR code were found, as well as some of the private key itself. By combining this with enhanced images of the blurred code, the team were able to put together less than one third of the QR code. The team had other tricks up their sleeve though – they knew the QR contained a private key of a particular format, and were able to figure out the QR code was 41×41 pixels.

By using this data along with a careful study of the QR code format, the team were able to put together some code in Python to brute force the key. After 838849 trials, the key was found, and the team were able to claim the prize. It’s a great example of cryptographic analysis – and so is this story on hacking your own password.

[Thanks to Esko for the tip!]

Password-Free Guest WiFi From Raspberry Pi

December 19, 2016 by Bryan Cockfield 31 Comments

Anytime you’re having more than a handful of people over to your place for a wild rager or LAN party (or both), you’ll generally need a way to make sure everyone can get their devices on the network. Normally, this would involve either putting your WiFi password into more phones than you can count or yelling your password across a crowded room. Neither of these options suited [NicoHood] and his partner, however, so he came up with another more secure solution to the WiFi-in-a-crowded-room problem.

He calls his project “guestwlan” and it’s set up to run on a Raspberry Pi with a touch screen. When a potential WiFi user approaches the Pi and requests access to the network, the Pi displays a QR code. Within that code is all of the information that the prospective device needs to connect to the network. For those who have already spotted the new security vulnerability that this creates, [NicoHood] has his guest WiFi on a separate local network just to make sure that even if someone nefarious can access the Internet, it would be more difficult for them to do anything damaging to his local network. As it stands, though, it’s a lot more secure than some other WiFi networks we’ve seen.

[NicoHood] also released his software on Git but it has been configured for use with Arch. He says that it would probably work in a Debian environment (which the Raspberry Pi-specific OS is based on) but this is currently untested. Feel free to give it a try and let us know how it goes.