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.
These days, everything’s got a clock in it, and a good proportion of those clocks are automatically syncronized to high-accuracy Internet time servers. Back in the past, things weren’t so easy. Often, institutions that required accurate time would use a single highly-accurate primary clock to drive a series of secondary clocks around a facility. Without the primary clock, the secondary clock has no signal to drive it. [Oleksii Samorukov] had just such a clock, and whipped up a controller to stand in for timekeeping duty.
The secondary clock in question is a Pragotron PJ 27, which requires regular 12V signals of alternating polarity in order to keep time. To handle this job, [Oleksii] decided to use an ESP32 in combination with an L298N motor controller. The L298N is an H-bridge driver chip, allowing it to easily supply the 12V signals in alternating polarities where required. To ensure the system keeps accurate time, the ESP32 regularly queries an NTP time server over WiFi.
It’s a tidy build, and one that brings this attractive 1960s timepiece into the modern era. We’d love to have such a stylish, well-built clock in our own home, too. Of course, if you want really accurate time, building a GPS clock is a great option, too!
Internet-connected sex toys are a great way to surprise your partner from work (even the home office) or for spicing up long-distance relationships. For some extra excitement, they also add that thrill of potentially having all your very sensitive private data exposed to the public — but hey, it’s not our place to kink-shame. However, their vulnerability issues are indeed common enough to make them regular guests in security conferences, so what better way to fight fire with fire than simply inviting the whole of Twitter in on your ride? Well, [Space Buck] built just the right device for that: the Double-Oh Battery, an open source LiPo-cell-powered ESP32 board in AA battery form factor as drop-in replacement to control a device’s supply voltage via WiFi.
Double-Oh Battery with all the components involved
In their simplest and cheapest form, vibrating toys are nothing more than a battery-powered motor with an on-off switch, and even the more sophisticated ones with different intensity levels and patterns are usually limited to the same ten or so varieties that may eventually leave something to be desired. To improve on that without actually taking the devices apart, [Space Buck] initially built the Slot-in Manipulator of Output Levels, a tiny board that squeezed directly onto the battery to have a pre-programmed pattern enabling and disabling the supply voltage — or have it turned into an alarm clock. But understandably, re-programming patterns can get annoying in the long run, so adding WiFi and a web server seemed the logical next step. Of course, more functionality requires more space, so to keep the AA battery form factor, the Double-Oh Battery’s PCB piggybacks now on a smaller 10440 LiPo cell.
But then, where’s the point of having a WiFi-enabled vibrator with a web server — that also happens to serve a guestbook — if you don’t open it up to the internet? So in some daring experiments, [Space Buck] showcased the project’s potential by hooking it up to his Twitter account and have the announcement tweet’s likes and retweets take over the control, adding a welcoming element of surprise, no doubt. Taking this further towards Instagram for example might be a nice vanity reward-system improvement as well, or otherwise make a great gift to send a message to all those attention-seeking people in your circle.
There is a scene from the movie RED (Retired, Extremely Dangerous) where Bruce Willis encounters a highly-secure door with a constantly changing lock code deep inside the CIA. Knowing the lock would be impossible to break, he simply destroyed the wall next to the door, reached through, and opened the door from the other side. We thought about that when we saw [raelize’s] hack to bypass the ESP32’s security measures.
Before you throw out all your ESP32 spy gadgets, though, be aware that the V3 silicon can be made to prevent the attack. V1 and V2, however, have a flaw that — if you know how to exploit it — renders secure boot and flash encryption almost meaningless.
Classic motorcycles are the wild west of information displays. Often lacking even basic instrumentation such as a fuel gauge and sometimes even a speedometer, motorcycles have come a long way in instrument cluster design from even 20 years ago. There’s still some room for improvement, though, and luckily a lot of modern bikes have an ECU module that can be tapped into for some extra information as [Sophie Wheeler] illustrates with her auxiliary motorcycle dashboard.
This display is built for a modern Honda enduro, and is based upon an ESP32 module. The ESP32 is tied directly into the ECU via a diagnostic socket, unlike other similar builds that interface with a CAN bus specifically. It can monitor all of the bike’s activity including engine temperature, throttle position, intake air temperature, and whether or not the bike is in neutral. [Sophie] also added an external GPS sensor so the new display can also show GPS speed and location information within the same unit.
We love getting our weather in a flurry of different methods, but have you tried building your own sensor suite to harvest the data for you? [Giovanni ‘CyB3rn0id’ Bernardo] needed to monitor isolated locations outside the reach of WiFi. His ray of hope is an ESP32 controller coupled with a LoRa module to beam data to a remote station that can access the cloud.
In addition to radios, he poured a deluge of sensors into the base station to read the temperature, barometric pressure, humidity, and fine dust. Why monitor dust as part of weather data collection? Particulate matter has a huge effect on air quality, something of great interest during a respiratory pandemic. For those readers near wildfires, quantifying your air quality (both indoors and out) is certainly of interest. [Giovanni] is using an SDS011 air quality sensor and has a long writeup just on this part. It uses a fan to move air past a laser-based sensing mechanism.
At the base station, live readings are shown on an OLED screen, but you can also connect to the ESP32 through your phone like a hotspot. If you keep a memory card installed, it will cache the readings in a perpetually-updated CSV file. In regular operation, the LoRa module overcasts the telemetry to its sister unit that acts as a Wifi/LoRa bridge so anyone can view gauges and graphs in real-time on ThingSpeak.
We want to shower [CyB3rn0id] with praise for seeing the cirrus serious impact of harmful dust and making something that can alert people. We don’t want to rain on anyone’s parade, but sometimes it is better to stay inside.
Unless you’re reading this from the middle of the ocean or deep in the forest, it’s a pretty safe bet there’s WiFi packets zipping all around you right now. Capturing them is just a matter of having the right hardware and software, and from there, you can get to work on cracking the key used to encrypt them. While such things can obviously have nefarious connotations, there are certainly legitimate reasons for auditing the strength of the wireless networks in the area.
It might not have the computational horsepower to crack any encryption itself, but the ESP32 M5Stack is more than up to the task of capturing WiFi packets if you install the Hash Monster firmware developed by [G4lile0]. Even if you don’t intend on taking things farther, this project makes finding WiFi access points and grabbing their packets a fascinating diversion with the addition of a few graphs and an animated character (the eponymous monster itself) that feeds on all those invisible 1s and 0s in the air.
