Our smartphones are incredibly powerful computers in their own right, yet we don’t often see them directly integrated into projects. Intel Intelligent Systems Lab has done exactly that with the release OpenBot, an open source smartphone based self-driving robot.
Most of the magic happens on the smartphone, which runs an app built on TensorFlow Lite, and integrates the camera and array of sensors on the smartphone, as well as the data from ultrasonic sensors and wheel encoders on the robot. The robot itself is relatively simple, with four geared DC motors, motor drivers wired to an Arduino Nano that interfaces with an Android Phone over serial.
The app created by the Intel ISL team comes preloaded with three AI models that can do either person following, or two different modes of autonomous navigation. By connecting a Bluetooth controller to the smartphone and drive the robot around manually in your specific environment while collecting data, you can train a custom autonomous driving policy to suit your environment.
This looks like an excellent way to get a taste of autonomous robots on a small budget, while still being a viable base for more demanding applications. We’ve seen only a few smartphone based robots like DriveMyPhone and SmartiPresense, which don’t have AI capabilities, but are intended for telepresence applications. We’ve always wondered why we don’t see more projects with cellphones, so we welcome the example.
Not every build needs to be immediately useful or revolutionary. Plenty of builds are just for fun, for education, or even purposefully useless but still challenging. This clock, for example, might fit into all three categories. It’s a clock that displays time through a QR code, making it completely inscrutable unless you have a device which likely has its own readable clock on it already.
The QR Code clock comes to us from [Aaron] and is based on the now-ubiquitous ESP32 WiFi chip. The ESP32 is connected to a 64×64 LED matrix which is updated every second with a code for the current time. With single-second resolution that means that even with a method for reading a QR code by hand, like you sometimes can with barcodes, there’s no way to read it without a smartphone since it changes so rapidly.
Of course [Aaron] recognizes the flaw in his design in his video in which he notes tongue-in-cheek that with this clock you would never have to look at a smartphone again, since the clock is right there on the wall. We appreciate the humor and also that [Aaron] has made all of his source code available in case you would like to use this as an example project for using QR codes for more useful purposes. For now, though, we’ll just forward you along to some other useless machines.
The design is based on an opensource metal detector called Smart Hunter. This Very Low Frequency (VLF) metal detector uses transmitter and receiver coils in so-called Double-D geometry. The transmitter coil is driven by a signal generator module that operates at its resonant frequency of 4.74 kHz.
The resulting oscillating magnetic field will induce eddy currents in a nearby metal object that in turn induce a signal in the receiver coil. This signal is then fed into the microphone port of a smartphone and analyzed by a custom metal detector app. [mircemk] also included an audio amplifier and small speaker into the device.
The detector turned out to be quite sensitive and can detect a coin at up to 25 cm distance and larger metal objects even up to 1 m. Modern metal detectors can also distinguish between different types of metal by analyzing the phase shift of the detected signal which might be some way to improve the design.
You don’t have to be an extinct mammal or a Millennial to enjoy the smooth, buttery taste of an avocado. Being psychic on the other hand is definitely an advantage to catch that small, perfect window between raw and rotten of this divaesque fruit. But don’t worry, as modern problems require modern solutions, [Eden Bar-Tov] and [Elad Goldberg] built the AvoRipe, a device to notify you when your next avocado has reached that window.
Taking both the firmness and color of an avocado as indicators of its ripeness into account, the team built a dome holding a TCS3200 color sensor as stand for the avocado itself, and 3D printed a servo-controlled gripper with a force sensor attached to it. Closing the gripper’s arms step by step and reading the force sensor’s value will determine the softness the avocado has reached. Using an ESP8266 as centerpiece, the AvoRipe is turned into a full-blown IoT device, reporting the sensor readings to a smartphone app, and collecting the avocado’s data history on an Adafruit.IO dashboard.
There is unfortunately one big drawback: to calibrate the sensors, a set of nicely, ripe avocados are required, turning the device into somewhat of a chicken and egg situation. Nevertheless, it’s a nice showcase of tying together different platforms available for widescale hobbyist projects. Sure, it doesn’t hurt to know how to do each part from scratch on your own, but on the other hand, why not use the shortcuts that are at our disposal to remove some obstacles — which sometimes might include programming itself.
[Labpacks] wanted to build a robot car controlled by his phone. As a Hackaday reader, of course you probably can imagine building the car. Most could probably even write a phone application to do the control. But do you want to? In most cases, you are better off focusing on what you need to do and using something off the shelf for the parts that you can. In [Labpacks’] case, he used Visuino to avoid writing ordinary code and RemoteXY to handle the smartphone interface.
RemoteXY is a website that allows you to easily build a phone interface that will talk to your hardware over Bluetooth LE, USB, or Ethernet (including WiFi). One thing of interest: even though the interface builder is Web-based, the service claims that the interface structure stays on the controller. There’s no interaction with the remote servers when operating the user interface so there is no need for an external Internet connection.
[Editor’s note: There’s an ongoing back-and-forth about this “spyware” right now. We haven’t personally looked into it on any phones, and decoded Wireshark caps of what the cleaner software sends home seem to be lacking — it could be innocuous. We’re leaving our original text as-run below, but you might want to take this with a grain of salt until further evidence comes out. Or keep us all up to date in the comments. But be wary of jumping to quick conclusions.]
This software in question is a “storage cleaner” in the “Device Care” section of the phone, which is supposed to handle file optimization and deletion. This particular application is made by a Chinese company called Qihoo 360 and can’t be removed from the phone without using ADB or having root. The company is known for exceptionally bad practices concerning virus scanning, and the software has been accused of sending all information about files on the phone to servers in China, which could then turn all of the data it has over to the Chinese government. This was all discovered through the use of packet capture and osint, which are discussed in the post.
These revelations came about recently on Reddit from [kchaxcer] who made the original claims. It seems to be fairly legitimate at this point as well, and another user named [GeorgePB] was able to provide a temporary solution/workaround in the comments on the original post. It’s an interesting problem that probably shouldn’t exist on any phone, let alone a flagship phone competing with various iPhones, but it does highlight some security concerns we should all have with our daily use devices when we can’t control the software on the hardware that we supposedly own. There are some alternatives though if you are interested in open-source phones.
If you’re the kind of person who hates this new generation of smartphone users and longs for a nostalgic past, you’re not far from the new target demographic for many commercial phone manufacturers. Major phone companies like Motorola and Huawei have been developing foldable versions of conventional smartphone designs, intended to be more versatile while maintaining the same functionality as their less flexible counterparts.
It’s certainly gimmicky, but phones like the Samsung Galaxy Fold, the Motorola Razr, and the Huawei MateX are elegant from an engineering perspective. Developing a seamless interface experience, maximizing surface area for functionality, and maintaining the same nostalgic flip phone aesthetic while making use of familiar smartphone features isn’t an easy design process.
For the Razr, a hinge system that takes up about a third of the phone’s internal space allows the OLED display to have no noticeable binder line. Rather than curving like a piece of paper, it forms a teardrop shape that prevents the screen from creasing and being damaged. Springs and pistons below the surface move small places underneath where the user will be tapping – folded in, the plates slide away. It’s an interesting effect, although as you can see in the banner image, it doesn’t quite achieve optically flat perfection.
In order to ensure that the screen doesn’t overheat as it bends, it is made up of microlayers sandwiched together. To balance weight, the circuits and battery is split into two, operating on each half of the device, an unusual design choice for smartphones. Placement of the array of radios and antennas is also a challenge since they can’t be too close to each other or the processor, which can interfere with signal transmission.
Other devices like the Royale Flexpai are more so proof-of-concepts making use of flexible screens and batteries, rather than capturing the aesthetics of a flip phone generation — but who doesn’t want their smartphone to unfold into a tablet when needed? The future of smartphone technology is looking interesting, and we’ll be sure to see even more iterations of flexible displays in the near future.