Category Archives: DIY

RFID Unlock Your PC, Because You’re 1337

Ever wanted to feel like one of those movie hackers from the late 90s? Yes, your basement’s full of overclocked Linux rigs and you’ve made sure all your terminal windows are set to green text on a black background, but that’s not always enough. What you need is an RFID tag that unlocks your PC when you touch the reader with your RFID cardOnly then may you resume blasting away at your many keyboards in your valiant attempts to hack the mainframe.

[Luke] brings us this build, having wanted an easier way to log in quickly without foregoing basic security. Seeing as an RC522 RFID reader was already on hand, this became the basis for the project. The reader is laced up with a Sparkfun Pro Micro Arduino clone, with both devices serendipitously running on 3.3V, obviating the need for any level shifters. Code is simple, based on the existing Arduino RC522 library. Upon a successful scan of the correct tag, the Arduino acts as a HID keyboard and types the user’s password into the computer along with a carriage return, unlocking the machine. Simple!

Overall, it’s a tidy build that achieves what [Luke] set out to do. It’s something that could be readily replicated with a handful of parts and a day’s work. If you’re interested in the underlying specifics, we’ve discussed turning Arduinos into USB keyboards before.

from Blog – Hackaday

Star Wars Lightsaber Bionic Arm from @openbionics #SciFiSunday

Absolutely wonderful!

via Adafruit

From Cop Car Data Terminal, To Retro Computer

It is possible that you will have lived your life without ever coming into contact with a Motorola MDT9100-T. The data terminal of choice for use in police cars across the globe was a computer with a full-sized QWERTY keyboard, a small CRT display, a mainboard sporting an Intel 386SX processor, and a custom version of Windows 3.1. [Trammell Hudson] and some friends from NYC Resistor scored some MDT9100s in an online auction and found them to be just too good an opportunity not to crack them open and see what could be done.

The custom Windows install could be bypassed with a DOS prompt for some period demoscene action, but [Trammell] wanted more. The 386SX wasn’t even quick when it was new, and this computer deserved the power of a BeagleBone! A custom cape was created on a prototyping cape to interface with the MDT9100 header carrying both keyboard and video. A bit of detective work revealed the display to be a 640×480 pixel mono VGA. The ‘Bone’s LVDS output can drive VGA through a resistor ladder DAC with the aid of an appropriate device tree overlay. The keyboard was then taken care of with a Teensy working as a USB device, resulting in a working Linux computer in the shell of an MDT9100.

It’s always good to see old technology brought up to date. Amusingly a couple of years ago we reported on the death of VGA, but retro projects like this one mean it’ll be a long time before we’ve heard the last of it.

from Blog – Hackaday

Control a Swarm of RC Vehicles with ESP8266

Over at RCgroups, user [Cesco] has shared a very interesting project which uses the ever-popular ESP8266 as both a transmitter and receiver for RC vehicles. Interestingly, this code makes use of the ESP-Now protocol, which allows devices to create a mesh network without the overhead of full-blown WiFi. According to the Espressif documentation, this mode is akin to the low-power 2.4GHz communication used in wireless mice and keyboards, and is designed specifically for persistent, peer-to-peer connectivity.

Switching an ESP8266 between being a transmitter or receiver is as easy as commenting out a line in the source code and reflashing the firmware. One transmitter (referred to as the server in the source code) can command eight receiving ESP8266s simultaneously. [Cesco] specifically uses the example of long-range aircraft flying in formation; only coming out of the mesh network when it’s time to manually land each one.

[Cesco] has done experiments using both land and air vehicles. He shows off a very hefty looking tracked rover, as well as a quickly knocked together quadcopter. He warns the quadcopter flies like “a wet sponge”, but it does indeed fly with the ESP’s handling all the over the air communication.

To be clear, you still need a traditional PPM-compatible RC receiver and transmitter pair to use his code. The ESPs are simply handling the over-the-air communication. They aren’t directly responsible for taking user input or running the speed controls, for example.

This isn’t the first time we’ve seen an ESP8266 take the co-pilot’s seat in a quadcopter, but the maniacal excitement we feel when considering the possibility of having our very own swarm of flying robots gives this particular project an interesting twist.

from Blog – Hackaday

Visible Light CT Scanner Does Double Duty

If you’ve ever experienced the heartbreak of finding a seed in your supposedly seedless navel orange, you’ll be glad to hear that with a little work, you can protect yourself with an optical computed tomography scanner to peer inside that slice before popping it into your mouth.

We have to admit to reading this one with a skeptical eye at first. It’s not that we doubt that a DIY CT scanner is possible; after all, we’ve seen examples at least a couple of times before. The prominent DSLR mounted to the scanning chamber betrays the use of visible light rather than X-rays in this scanner — but really, X-ray is just another wavelength of light. If you choose optically translucent test subjects, the principles are all the same. [Jbumstead]’s optical CT scanner is therefore limited to peeking inside things like slices of tomatoes or oranges to look at the internal structure, which it does with impressive resolution.

This scanner also has a decided advantage over X-ray CT scanners in that it can image the outside of an object in the visible spectrum, which makes it a handy 3D-scanner in addition to its use in diagnosing Gummi Bear diseases. In either transmissive or reflective mode, the DSLR is fitted with a telecentric lens and has its shutter synchronized to the stepper-driven specimen stage. Scan images are sent to Matlab for reconstruction of CT scans or to Photoscan for 3D scans.

The results are impressive, although it’s arguably more useful as a scanner. Looking to turn a 3D-scan into a 3D-print? Photogrammetry is where it’s at.

from Blog – Hackaday

ROVER the singing robot #piday #raspberrypi @Raspberry_Pi

Rover the Singing Robot from UC Santa Barbara on Vimeo.

UC Santa Barbara grad student, Hannah Wolf created ROVER. This awesome project was built with a Roomba, some sensors, an Arduino and of course, a Raspberry Pi.

Via Nanowerk:

“I wanted to create an interactive art installation that would make people happy,” said Wolfe, who is based in the rather austere environment at UCSB’s Elings Hall. “I thought if something came up to people and sang to them that would bring joy into the space.”

With a Roomba (sans vacuum) as its feet, a Raspberry Pi as its brain and an Arduino acting as a nervous system, Rover is more than an artistic endeavor, however. It is also a tool for investigating the ways humans respond to robots.

Think about it: We ask iPhone’s Siri or Amazon’s Alexa for help accessing information, making purchases or operating Bluetooth-enabled devices in our homes. We have given robots jobs that are too tedious, too precise or too dangerous for humans. And artificial intelligence is now becoming the norm in everything from recommendations in music and video streaming services to medical diagnostics.

“Whether we like it or not, we’re going to be interacting with robots,” Wolfe said. “So, we need to think about how we will interact with them and how they will convey information to us.”

To that end, Wolfe has ROVER generate sounds — beeps and chirps and digital effects (think R2D2) — that she found elicit positive versus negative reactions from people. Meanwhile an onboard camera records how individuals respond to ROVER.

Read more!

3055 06Each Friday is PiDay here at Adafruit! Be sure to check out our posts, tutorials and new Raspberry Pi related products. Adafruit has the largest and best selection of Raspberry Pi accessories and all the code & tutorials to get you up and running in no time!

via Adafruit

Capacitive And Resistive Touch Sensors For Wearables

When you look at switching solutions for electronic wearables, your options are limited. With a clever application of conductive fabric and thread, you can cobble together a simple switch, but the vast array of switch solutions is much more than that. This one is different. The zPatch from [Paul Strohmeier], [Jarrod Knibbe], [Sebastian Boring], and [Kasper Hornæk] at the Human-Centred Computing Section at the University of Copenhagen gives eTextiles capacitive and resistive input. It’s a force sensor, a pressure sensor, and a switch, all made completely out of fabric.

The design of this fabric touch sensor is based around a non-woven resistive fabric made by Eeonyx. This fabric is piezo-resistive when compressed. This material is sandwiched between two layers of silver-plated polyamide fabric, which is then connected to the analog input of a microcontroller. On top of all this is a polyester mesh, with everything held together with iron-on sheets.

Reading this sensor with a microcontroller is extremely similar to a capacitive touch sensor made out of copper and FR4. All the code is available in a repo, and all the materials to reproduce this work can be found in the various links provided by the team. That last point — reproducibility — is huge for an academic work. Not only did the team manage to come up with something interesting, they actually provided enough documentation to reproduce their build.

In the video below, you can see how this sensor can be used to sense a hand hovering, a light touch, a hard press, or anything in between. Only two analog pins are required for each sensor, making the routing and layout of this eTextile should be relatively easy to integrate into clothing. It’s a great build, and we can’t wait to see the community pick up on these really cool sensors.

from Blog – Hackaday