Kritik sah

Lots of music events these days hand out various glowing tchotchkes that flash and sync up with the performance. [Tony Goacher] has whipped up his own badges that can do just that, all without needing any sort of pairing or infrastructure to speak of. The CrowdClock badges each feature a ring of 16 addressable RGB LEDs. Running the LEDs is an ESP32 microcontroller, which has lots of neat wireless capability baked in from the factory. [Tony] decided to leverage the ESP-NOW wireless communication protocol to enable each badge to broadcast its current local clock tick. Each device also listens out for clock ticks from other badges in the area, and updates its current clock tick value if it receives a higher one from another badge. This behaviour allows a bunch of badges within radio range to all sync up automatically in short order, and then run their LED sequences in sync. There’s no need for a master designation or anything, the devices just all sync to whichever badge has the hig...

In a recent video  [Saša Karanović] revisits the DIY filament dryer that he gave a shot a couple of years ago. Back then he reused an existing filament dryer, adding a custom controller and such to improve its performance. This technically-not-fully-DIY dryer got some feedback since then, and thus the V2 version is an example of how to better DIY such a dryer, including a custom PCB and a GitHub project for all the details. Those who just want to dive into the documentation for assembly and the BOM can look at the available documentation . At its core the whole assembly consists of some kind of container like the shown 5L food storage type, along with an SHT30 temperature and humidity sensor and 100K NTC temperature sensor. These connect to the controller board which then switches on or off the 12V polymide resistive heater. One thing that could be improved here is that the saturated warm air has nowhere to go. This is a common issue with filament dryers and why it’s recommende...

A potentiometer is a simple electrical device that allows resistance to be varied at will. Most everyone in the electronics field is intimately familiar with how they work on a fundamental level. Of course, we all had to be taught once, though, and a great way to do that would be with a teaching tool like the one [DiscoLapy] built . What you’re looking at here is a very simple potentiometer that bares its function for all to see. It consists of a 3D printed base and knob, which form the mechanical part of the device. A paper track is then laid on top to act as the main resistive element, once properly covered with graphite from a regular old pencil. From there, it’s as simple as adding the necessary contacts and wiper to the device, and you’ve got a potentiometer sitting in front of you. What’s great about this build is that it’s very intuitive. Just by looking at it or putting it together, you get a straightforward understanding of everything that’...

Magnetic fields are all around us. We can’t really feel or see them ourselves, per se, but we can map them with the right hardware, like this device built by [edosari50]. The build uses an ESP32 microcontroller, which is built on to a board with an integrated 4.3″ touchscreen LCD. It’s paired with an Arduino Nano, which does the work of actually talking to a pair of EMS100 Fluxgate magnetic sensors. The slower, less capable Arduino handles the low-level chatter and then passes the readouts to the ESP32 over a UART connection. Power is courtesy of a pair of 18650 lithium-ion cells, and a XL4005 DC-DC converter. A lithium-ion charging module is on hand to keep the batteries topped off safely.  Scan results are visualized on the device itself using a heatmap representation, and can also be exported to SD card for later analysis if so desired. Unless you’re in the geological field or otherwise hunting for stuff underground, this probably isn’t a tool you...

Even [maurycyz] doesn’t think it is a good idea, but it is possible to use an AVR 8-bit CPU to serve web pages . Of course, it is a vastly simplified web server, but it does serve pages — OK, technically just one page  — to the public Internet. Working backward, it is fairly easy to get the microcontroller to note an HTTP request and then simply spit out a prerecorded HTTP response to provide the page. The hard part is connecting the little processor to the network. The server is dead simple, just a CPU and a scant number of components like filter caps and LEDs. The trick is to use SLIP , an ancient protocol used to connect dial-up modem terminals to the network. Linux supports SLIP, so the MCU connects to a Linux computer via SLIP. Then the Linux computer uses WireGuard to network with the remote web server that serves [maurycyz’s] site. The SLIP implementation assumes that IP packets aren’t fragmented, which is normally true these days. TCP was a bit mo...

One of the problems with good science fiction is that it introduces us to all kinds of cool devices that we can’t actually have in real life. [Huy Vector] has tried to fix that a little with this fantastic smartwatch build inspired by everybody’s favorite wrist computer from the Fallout series . The build is based around a Xiao ESP32-S3 board, which hosts the capable microcontroller and has all that useful wireless connectivity built in. It’s hooked up to a MAX30102 heart rate sensor to collect the wearer’s vital signs, as well as a 1.54″ LCD screen for displaying the fantastic Pip Boy themed interface. Power is courtesy of a small lithium-ion cell tucked in behind the display. A little copper tubing and brass hardware helps tie everything together, with the latter serving as capacitive touch points for controlling the device. A simple leather watch strap completes the build. It’s a bit of a diversion from the classic Pip Boy design, in that it...