Navigating The Dark Side: Controlling Robots With Zero Radio Communication

October 20, 2019 by Sharon Lin 15 Comments

While autonomous robots have been the subject of some projects in the past, this particular project takes a swing at building a robot that can teach children about controls and robotics.

The idea is to mimic a space mission on the dark side of the moon, where radio contact is nearly impossible. The students learn to program and debug embedded devices and sensors, even before some of them have learned the alphabet!

The material for the challenge allows the microcontroller to be programmed in a simple Arduino program (Blink) as well as lower level languages like C++ or Java. The main hardware consists of an Arduino Uno R3-based rover controlled over WiFi by an ESP8266. The sensor data from the robot is gathered from an ultrasound distance sensor an a camera, as well as a SIM7000E GSM+GPS. Commands are polled from a server, sent via a web page and REST interface.

The rover responds to commands for directions, takes pictures, and scans its distance remotely. Some custom libraries are written for the serial communication and camera to account for spotty communication. The latest challenge expansion is a probe that pays attention to battery life and power consumption, challenging students to account for power usage during the robot’s lifetime.

Since the project’s conception, the rovers have already been used in schools, and we’re excited to see a new approach for younger students to learn controls and programming.

Making A Robot Cleaner Even Smarter

October 20, 2019 by Sharon Lin 9 Comments

Some electric cleaners are effective and some hardly even seem to make a difference. The ILIFE V7s may be a robot cleaner, but even with its cleaning modes and anti-collision system, it still requires IR signals to complete any tasks. Tired of having to be physically in the same place as his robot cleaner, [pimuzzo] decided to take matters into his own hands and build a RESTful remote control to send IR signals from afar.

The program uses the ESP8266WebServer and IRremoteESP8266 libraries for handling HTTP requests and sending and receiving infrared signals. The remote also respond to Actions on Google for controlling the robot over a Google Assistant.

The IR signals are a bit funky – as one user highlighted, finding the IR protocol is a nontrivial task that can be accomplished by recording the IR signals from the original remote with a IR receiver and matching the marks, spaces, and carrier frequency with those of known protocol codes. [Oitzu] was able to match the timing to the NEC 32 bit protocol and find the exact codes on an oscilloscope, which simplified the translation of the codes for the remote.

Sometimes when life gives you a robot cleaner, it’s your job to make it smarter.

Beam Me Up To The PCB Space Ship

October 19, 2019 by Sharon Lin 15 Comments

This project would fit in perfectly with #BadgeLife if someone could figure out a way to hang it from their neck. Inspired by Star Trek’s Starship Enterprise, [bobricius] decided to design and assemble a miniature space ship PCB model, complete with 40 blinking LEDs controlled by an ATtiny85.

While the design uses 0603, 0802, 3014, 4014, and 0805 LEDs, some substitutions can be made since the smallest LEDs can be difficult to solder. The light effects include a green laser, plasma coils, a deflector with scrolling blue LEDs, and the main plate and bridge for the space ship.

The LEDs are controlled by charlieplexing, a technique for driving LED arrays with relatively few I/O pins, different from traditional multiplexing. Charlieplexing allows n pins to drive n²−n LEDs, while traditional multiplexing allows n pins to drive (n/2)² LEDs. (Here is the best explanation of Charlieplexing we’ve ever seen.)

Especially with the compiled firmware running on the MCU, the PCB model makes for an impressive display.

The only catch? Your Starship Enterprise can’t actually fly.

Continue reading “Beam Me Up To The PCB Space Ship” →

Customizing Xiaomi ARM Cortex-M Firmware

October 19, 2019 by Sharon Lin 2 Comments

This hack was revealed a while ago at DEFCON26, but it’s still a fascinating look into vulnerabilities that affect some of the most widely used IoT devices.

[Dennis Giese] figured out a way to modify ARM Cortex-M based firmware for use in customizing the functionality of devices or removing access to the vendor. Obviously, there are more malicious activities that can be done with this type of hack, as with any exploits of firmware, but they are (also) obviously not condoned.

The talk goes into the structure of Xiaomi ecosystem and products before going into a step-by-step approach to binary patching the firmware. The first step was to acquire the firmware, either by dumping SPI flash memory (using JTAG, SWD, or desoldered Flash pins) or intercepting traffic during a firmware update and downloading the firmware. There’s also a possibility of downloading the firmware using a URL, although this can be more difficult to find.

The firmware can then be parsed, which first requires the format to be converted from a proprietary format to and ELF file. This conversion makes it easier to load into IDA pro, and gives information on the segments of the firmware and its entry point. Python tools luckily exist for converting binary files to ELF, which simplifies the task.

After loading the ELF file into the disassembler, you’ll want to find the key memory area, denoted by “TAG_MAC”, “TAG_DID”, and “TAG_KEY” in the example firmware (for storing the MAC address, device ID, and key). In order to prepare the firmware for Nexmon – a software that supported C-based firmware binary patching for ARM Cortex-A and ARM Cortex-M binaries – you’ll need to partition some space in the memory for patches and know the function names and signatures for the firmware.

The latter is done by doing a difference comparison in the disassembler between an unknown executable and the example executable.

With the necessary information gathered, you can now use Nexmon to make your modifications. The fact that this can be done for smart devices at home means that smart devices you acquire – especially those partitioned by others – may contain malicious code, so take care when handling used devices.

Continue reading “Customizing Xiaomi ARM Cortex-M Firmware” →

There’s More To The 3D Print Than The Eye Can See

October 19, 2019 by Sharon Lin 11 Comments

If you thought CADing designs for 3D printing was hard enough, wait until you hear about this .stl trick.

[Angus] of Maker’s Muse recently demoed a method for creating hidden geometries in .stl files that are only revealed during the slicing process before a 3D print. (Video, embedded below.) The process involves creating geometries with a thickness smaller than the size of the 3D printer’s nozzle that still appear to be solid in a .stl editor, but will not be rendered by a FDM slicer.

Most 3D printers have 0.4 mm thickness nozzle, so creating geometries with a wall thinner than this value will result in the effect that you’re looking for. Some possible uses for this trick are to create easter eggs or even to mess with other 3D printing enthusiasts. Of course, [Angus] recommends not to use this “deception for criminal or malicious intent” and I’d have to agree.

There’s a few other tricks that he reveals as well, including a way to create a body that’s actually a thin shell but appears to be solid: great for making unprintable letters that reveal hidden messages.

Nevertheless, it’s a cool trick and maybe one of those “features not bugs” in the slicer software.

Continue reading “There’s More To The 3D Print Than The Eye Can See” →

Converting A Tesla To A Pickup Truck

October 19, 2019 by Sharon Lin 38 Comments

The renowned inventor of useless robots [Simone Giertz] has outdone herself this time. She, along with a team of engineers featuring [Rich Rebuilds], [Laura Kampf], and [Marcos Ramirez], recently decided to convert a Tesla into a pickup truck, and make a video along the way, all while salvaging what remains they can of the back of the car and making the final product roadworthy. Yeah, this is a couple weeks old now, and yeah, it’s kind of a commercial, but really: [Simone Giertz] and Co. rock.

In her vlog of the experience, the team starts by gutting out the interior of the car in order to find out the weight distribution and form of the outer frame. Essentially, in order to create the pickup truck, a portion of the back of the car needs to be removed, with additional beams and support welded in depending on the consequent structural integrity. With a sawzall and angle grinder, the top portion of the frame is cut and taken out, but not before a worrying glance brings about the realization that the car needs exterior support during its modifications.

After the cushions, glass, wiring, and all other accessories are removed, they install a truck bed from another sacrificial pickup truck, as well as a roof rack to complete the look. Amidst the deconstruction and reconstruction, there are moments when the car encounters a “Safety restraint system fault” or when the team accidentally lines the inside of the car with fiberglass right before shooting their video. Between complaints of the different clip sizes used and the clear time pressure of the project, it’s a funny and informative look into a pretty unique car mod.

The final commercial they made of their Tesla-pickup hybrid, dubbed Truckla, is available on [Giertz]’s YouTube channel.

Continue reading “Converting A Tesla To A Pickup Truck” →

File Compression By Steganography

October 19, 2019 by Sharon Lin 29 Comments

In a world with finite storage and an infinite need for more storage space, data compression becomes a very necessary problem. Several algorithms for data compression may be more familiar – Huffman coding, LZW compression – and some a bit more arcane.

[Labunsky] decided to put to use his knowledge of steganography to create a wholly unique form of file compression, perhaps one that may gain greater notoriety among other information theorists.

Steganography refers to the method of concealing messages or files within another file, coming from the Greek words steganos for “covered or concealed” and graphe for “writing”. The practice has been around for ages, from writing in invisible ink to storing messages in moon cakes. The methods used range from hiding messages in images to evade censorship to hiding viruses in files to cause mayhem.

The developer explains that since every file is just a bit sequence, observing files leads to the realization that a majority of bits will be equal on the same places. Rather than storing all of the bits of a file, making modifications to the hard drive at certain locations can save storage space. What is important to avoid, however, is lossy file compression that can wreak havoc on quality during the compression stage.

The compression technique they ended up implementing is based on the F5 algorithm that embeds binary data into JPEG files to reduce total space in the memory. The compression uses libjpeg for JPEG decoding and encoding, pcre for POSIX regular expressions support, and tinydir for platform-independent filesystem traversal. One of the major modifications was to save computation resources by disabling a password-based permutative straddling that uniformly spreads data among multiple files.

One caveat – changing even one bit of the compressed file could lead to total corruption of all of the data stored, so use with caution!