Like so many of us, [aforsberg] found themselves fascinated with the WOPR computer from WarGames — something about all those blinking LEDs must speak to nerds on some subconscious level. But rather than admire the light show from afar, they decided to recreate it at a scale suitable for a 1U server rack.

So what goes into this WOPR display? In this case, the recipe simply calls for three MAX7219 dot matrix LED modules and a Raspberry Pi Pico, although you could swap that out for your favorite microcontroller if you wish. You should probably stick with something that at least runs MicroPython though, or else you won’t be able to use the included Python code to mimic the light patterns seen in the film.

What we like most about this project is how simple and inexpensive it is to recreate. There’s no custom PCB, and all the parts are mass produced enough that the economies of scale have made them comically cheap. Even at Amazon prices, you’re looking at around $50 USD in parts, and quite a bit less if you’ve got the patience to order everything through AliExpress.

Critics will note that, in its current state, this display just shows gibberish (admittedly stylish gibberish, but still). But as we’ve seen with similar projects, that’s simply a matter of software.

Logically we understand that the other planets in the solar system, as well as humanity’s contributions to the cosmos such as the Hubble Space Telescope and the International Space Station, are zipping around us somewhere — but it can be difficult to conceptualize. Is Jupiter directly above your desk? Is the ISS currently underneath you?

If you’ve ever found yourself wondering such things, you might want to look into making something like Space Monitor. Designed by [Kevin Assen], this little gadget is able to literally point out the locations of objects in space. Currently it’s limited to the ISS and Mars, but adding new objects to track is just a matter of loading in the appropriate orbital data.

In addition to slewing around its 3D printed indicator, the Space Monitor also features a round LCD that displays the object currently being tracked, as well as the weather. Reading through the list of features and capabilities of the ESP32-powered device, we get the impression that [Kevin] is using it as a sort of development platform for various concepts. Features like remote firmware updates and the ability to point smartphones to the device’s configuration page via on-screen QR aren’t necessarily needed on a personal-use device, but its great practice for when you do eventually send one of your creations out into the scary world beyond your workbench.

If you’re interested in something a bit more elaborate, check out this impressive multi-level satellite tracker we covered back in 2018.

Starting a new microcontroller project can be pretty daunting. While you have at least a rough idea of where you want to end up, there are so many ways to get there that you can get locked into “analysis paralysis” and never get the project off the ground. Or arguably worse, you just throw whatever dev board you have in the junk bin and deal with the consequences.

While it’s hard to go wrong with relying on a familiar MCU and toolchain, [lcamtuf] argues in this recent guide to choosing microcontrollers that it’s actually not too much of a chore to make the right choice. Breaking the microcontroller universe down into three broad categories makes the job a little easier: simple process control, computationally intensive tasks, and IoT products. Figuring out where your project falls on that spectrum narrows your choices considerably.

For example, if you just need to read some sensors and run a few servos or solenoids, using something like a Raspberry Pi is probably overkill. On the other hand, a Pi or other SBC might be fine for something that you need wireless connectivity. We also appreciate that [lcamtuf] acknowledges that intangible considerations sometimes factor in, such as favoring a new-to-you MCU because you’ll get experience with technology you haven’t used before. It might not override technical considerations by itself, but you can’t ignore the need to stretch your wings once in a while.

There’s nothing earth-shattering here, but we enjoy think pieces like this. It’s a bit like [lcamtuf]’s recent piece on rethinking your jellybean op-amps.

The ESP32 family are the microcontrollers which just keep on giving, as new versions keep them up-to-date and plenty of hackers come up with new things for them. A popular device is a general purpose computer with a QWERTY keypad, and the latest of many we’ve seen comes from [StabbyJack]. It’s a credit card sized machine whose special trick is that its keyboard is integrated in the 3D printing of its case. We’ve seen rubber membranes and push in keys, but this one has flexible print-in-place keys that line up on the switches on its PCB.

It’s not complete yet but the hardware appears to be pretty much there, and aside from that keyboard it has an ESP32-S3 and a 1.9″ SPI LCD. When finished it aims for an ambitious specification, with thermal camera and time-of-flight range finder hardware, along with an OS and software to suit. We like it a lot, though we suspect it might be a little small for our fingers.

If you like this project you may appreciate another similar one, and perhaps your version will need an OS.

Those little ESP32-CAM boards which mate the WiFi-enabled microcontroller with a small parallel-interface camera module have been with us for years, and while they are undeniably cool to play with, they sometimes stretch the available performance in trying to process and stream video. [Mattsroufe] has made a very cool project with one of them, not only managing to stream video from a small model car, but also to control the steering and motor by means of servos and a little motor driver.

Sadly it’s not entirely a stand-alone device, as the ESP32 streams video to a web server with some Python code to handle the controls. The server can aggregate several of them on one page though, for perhaps a little real-life quad-screen Mario Kart action if you have enough of the things. We can see that this idea has plenty of potential beyond the mere fun of driving a toy car around though, but to whet your appetite there’s a demo video below.

We’ve seen enough of the ESP32-cam before, but perhaps more as a photographic device.

The crux of most supercomputers is the ability to operate on many pieces of data at once — something video cards are good at, too. Enter T1 (short for Torrent-1), a RISC-V vector inspired by the Cray X1 vector machine.

T1 has support for features, including lanes and chaining. The chip contains a version of the Rocket Core for scalar operations, but there’s no official support for using it. The project claims you could easily replace that core with any other RISC-V CPU IP.

By focusing on parallelism instead of out of order execution, the design gets to skip branch prediction, register renaming, and similar problems.

There is an emulator if you want to experiment. You can even grab a docker image for easy installation. This doesn’t look like something you could pick up in an hour, so prepare to spend some time. Everything is bare-metal, too, so leave your favorite development tools at home.

The project uses Chisel, which we’ve covered before. The build system seems very complex, but based on Nix Flakes, so it should be understandable.

If your high-performance RISC-V dreams are more conventional, there’s work going on in that area, too.

Title graphic from Freepik.

It isn’t that hard to make an electronic rain gauge if you have a steady source of power or you don’t mind changing batteries often. But [Matthew Ford] offers a third option: a simple device with a Bluetooth Low Energy (BLE) module that can get a few years of a pair of AA batteries.

The approach has several advantages. Batteries make the device self-contained, and changing them infrequently is an obvious win. In addition, the BLE allows the device to be wireless and send data directly to an Android device. Thanks to a WH-SP-RG rain gauge, there’s not much to that part. The smart part is an nRF52832 module and some minor parts. The phone side uses an off-the-shelf Android app.

In a project like this, it is critical to have timers that really put the CPU to sleep. [Matthew] had to modify the Arduino libraries to allow the lp_timer objects to make it to an hour. Without the modifications, the timer can only reach 8.5 minutes. Sure, you could stack them, but that means taking a power hit multiple times an hour which would affect battery life.

Not the most complex project, but more complexity would mean lower battery life, so — as they say — less is more. We couldn’t help but think that with rechargeable batteries and a small solar panel, this could last a very long time.

LoRa, of course, is another choice. You can make 3D print a tipping bucket device, too.

These days, turn-by-turn GPS navigation isn’t considered special anymore. It’s in every smartphone and most cheap rental cars, and thus everybody expects you to figure out where you’re going. If you want a simpler and less robust navigation experience, you might like to try the rather fancy RadioScout.

The RadioScout is a build from [hardlyhumanfx]—a group of engineers and artists that collaborate on fun and whimsical projects. It looks like some kind of steampunk compass, and it kind of is—but at heart, it’s powered by GPS.

You program the RadioScout using the buttons on the front panel and a rotary phone dial to enter the latitude and longitude of your destination. It then uses an internal GPS receiver to compare that with your current location, and calculates a direct bearing to where you want to go. This bearing is displayed with a large compass-like needle run by a stepper motor, and you you can use it to guide yourself onwards.

It’s an attractive build that uses lots of neat parts. The team interfaced a microcontroller with a GPS receiver, a rotary dial, and 7-segment LEDs for the latitude and longitude display. The very real bell is neat, too. The whole thing is wrapped up in a brass and wooden case that would make you a star at just about any sci-fi convention. The build video is a little vague on the finer details, but experienced makers will be able to figure out how it all works.

You can actually buy a RadioScout if it’s something you must have, but one suspects the Hackaday set would probably prefer the homebrew route.

@hardlyhumanfx

#steampunk gps i designed and built. this is just a rough prototype

♬ original sound – HardlyHumanFX

@hardlyhumanfx

as promised, a field test of the antique working GPS system I built! Available to buy now on our website HardlyHumanFX.com #steampunk #fallout #vintage

♬ original sound – HardlyHumanFX

Thanks to [Charles] for the tip!

GOG y Capcom han lanzado Dino Crisis y su secuela Dino Crisis 2 para PC a través de GOG por US$ 9.99 cada uno, anunciaron las compañías, o un paquete que contiene ambos juegos por US$ 16.99.

Como todos los títulos de la plataforma, ambos títulos están libres de DRM con su contenido original completamente intacto y son parte del Programa de Preservación de GOG que presenta varias mejoras en la calidad de vida y compatibilidad optimizada para funcionar sin problemas en computadoras modernas y futuras.

«Dino Crisis de Capcom ha dejado una huella increíble en el género de terror de supervivencia con su intensa atmósfera y suspenso impulsado por los dinosaurios, ganándose su lugar como un clásico.

El primer juego ahora es compatible con Windows 10/Windows 11 e incluye los modos Operation Wipe Out Original, Arrange y exclusivo para PC.

Las actualizaciones incluyen renderizado DirectX mejorado, resolución ~4K, controladores modernos y correcciones de estabilidad, transparencia y problemas de guardado. Nuevas opciones como V-Sync, Corrección Gamma y Anti-Aliasing ofrecen una experiencia refinada.»

GOG también anunció el lanzamiento de GOG Dreamlist, una evolución de Community Wishlist, que permite a los usuarios votar qué juegos quieren que GOG reviva.

«GOG Dreamlist es una forma de decirnos: ‘Este juego me importa’ y de ayudarnos a convencer a los editores para que lo recuperen», dijo GOG en un comunicado de prensa. “Sus votos mantienen el fuego encendido, incluso cuando las negociaciones se vuelven difíciles, por los juegos por los que vale la pena luchar”.

Acerca de Dino Crisis

Hace tres años. Un científico murió en un accidente durante un experimento. Su investigación se centró en la «Tercera Energía», una fuente de energía completamente limpia.

El accidente ocurrió justo cuando se había cortado el financiamiento del gobierno porque el proyecto se consideró inviable. Para el público, no era más que un dato insignificante. Hasta ahora.

Un agente enviado a un pequeño país en los Mares del Sur para investigar un proyecto militar de alto secreto trajo información sorprendente.

En un centro de investigación militar de la República de Borginia, un científico que debía haber muerto hace tres años en nuestro país ha reanudado sus actividades de investigación en el campo de la Tercera Energía. Regina, miembro del equipo de espionaje del gobierno, se encargó de recuperar al médico.

Se dirige a la aislada isla de Ibis, donde se encuentra la instalación militar. La élite oscura está entrenada para todos los desafíos imaginables. Para ellos, es un «trabajo» más, como siempre…

Características de Dino Crisis para GOG:

• Compatibilidad total con Windows 10 y Windows 11
• Las 6 localizaciones del juego incluidas (inglés, alemán, francés, italiano, español y japonés)
• Modos Original, Arrange y Operation Wipe Out incluidos
• Renderizador de juegos DirectX mejorado
• Nuevas opciones de renderizado (Modo de ventana, Control de sincronización vertical, Corrección gamma, Integer Scalig, Anti-aliasing y más)
• Se ha aumentado la resolución de renderizado a ~4K (1920p) y la profundidad de color a 32 bits.
• Cálculo de geometría mejorado, transformación y texturizado más estables.
• Transparencia alfa mejorada
• Configuración mejorada del registro de juegos
• Reproducción de animación, vídeo y música sin problemas
• Guardado sin problemas (el juego ya no corrompe los archivos guardados después de dejar las armas caídas)
• Soporte completo para controladores modernos (Sony DualSense, Sony DualShock4, Microsoft Xbox Series, Microsoft Xbox One, Micro

Requisitos Mínimos:

• SO: Windows 10/11 de 64 bits
• Procesador: de 2GHz
  
• Memoria: 2GB
• Gráficos: 100% Compatible con DirectX 9.0c
  
• DirectX: Versión 11
• Almacenamiento: 600 MB de espacio disponible

Acerca de Dino Crisis 2

Ha pasado un año desde la operación para recuperar al Dr. Kirk. La Tercera Energía, tanto una fuente de «energía limpia definitiva» como un potencial «arma definitiva», ha demostrado ser peligrosamente impredecible. El gobierno, habiendo tomado el control del proyecto del Dr. Kirk, continuó su desarrollo. Entonces, el «accidente» ocurrió una vez más.

La ciudad de investigación de Edward City fue completamente destruida en una explosión del reactor de Tercera Energía, un evento mucho más catastrófico que el accidente anterior. En respuesta, el gobierno lanzó una misión de rescate para recuperar los datos de la investigación y el personal restante.

Para llegar a Edward City, que se cree que fue desplazada en el tiempo por la explosión del reactor, el gobierno desplegó un dispositivo experimental no probado de «puerta del tiempo» para enviar un equipo de rescate al pasado. Nadie podía prever las consecuencias de esta misión, excepto una persona: Regina…

Características de Dino Crisis 2 para GOG:

• Compatibilidad total con Windows 10 y Windows 11
• Las 2 localizaciones del juego incluidas (inglés, japonés)
• Dificultad fácil, Dino Colosseum y Dino Duel incluidos
• Renderizador de juegos DirectX mejorado
• Nuevas opciones de renderizado (Modo de ventana, Control de sincronización vertical, Corrección gamma, Integer Scaling, Anti-aliasing y más)
• Reproducción de música y escalado de volumen mejorados
• Se ha mejorado el renderizado y el empañamiento de los elementos.
• Alineación mejorada de las cajas de cartuchos
• Reproducción de vídeo, cambio de tareas y salida de juegos sin problemas
• Compatibilidad total con mandos modernos (Sony DualSense, Sony DualShock4, Microsoft Xbox Series, Microsoft Xbox One, Microsoft Xbox 360, Nintendo Switch, Logitech F series y muchos más) con una asignación de botones óptima independientemente del hardware y el modo inalámbrico

Requisitos Mínimos:

• SO: Windows 10/11 de 64 bits
• Procesador: de 2GHz
  
• Memoria: 2GB
• Gráficos: 100% Compatible con DirectX 9.0c
  
• DirectX: Versión 11
• Almacenamiento: 650 MB de espacio disponible

La entrada Dino Crisis y Dino Crisis 2 se relanzan en GOG con Mejoras Gráficas, Soporte para 4K, Mandos Modernos y más – Trailer apareció primero en PC Master Race Latinoamérica.

If you’re lucky enough to work from home, you’ll soon find that it presents its own set of challenges, mostly related to work/life balance. It can get so bad that you don’t know what day of the week it is. Really. Ask us how we know.

Rather than miss a meeting (or a day off), prolific hacker [Arnov Sharma] created this day of the week clock. It uses a customized LED driver board with seven sets of three LEDs, each driven by a MOSFET. Each MOSFET is controlled by a DFRobot Mini Beetle ESP32-C3. It runs on a 2200 mAh, 3.7 V lithium-ion battery.

While this is mostly PCBs, there are three printed parts that turn it into a displayable object. We really like the look of this clock — it has just the right amount of pizazz to it and reminds us of a and old movie marquee. Be sure to check out the great build instructions.

We love a good clock around here. In case you missed it, here is the latest from [Moritz v. Sivers] that uses a caustic lens to display the time.

Wielding things like two-handed swords in VR can be awkward. There’s no sense of grasping a solid object. The controllers (and therefore one’s hands) feel floaty and disconnected from one another, because they are. [Astro VR Gaming] aims to fix this with a DIY attachment they are calling the ARC VR Sword Attachment.

The ARC is a 3D-printed attachment that allows a player to connect two controllers together. They can just as easily be popped apart, which is good because two separate controllers is what one wants most of the time. But for those moments when hefting a spear or swinging a two-handed sword is called for? Stick them together and go wild.

The original design (the first link up above) uses magnets, but an alternate version uses tapered inserts instead, and provides a storage stand. Want to know if the ARC is something you’d like to make for yourself? Watch it in action in the video embedded just under the page break.

VR is an emerging technology with loads of space for experimentation and DIY problem solving. We wish more companies would follow Valve’s example of hacker-friendly hardware design, but even just providing CAD models of your hardware to make attachments easier to design would be a big step forward, and something every hacker would welcome.

One of the best things about adulthood is that finally we get to, in most cases, afford ourselves the things that our parents couldn’t (or just didn’t for whatever reason). When [Yakroo108] was a child, Walkmans were expensive gadgets that were out of reach of the family purse. But today, we can approximate these magical music machines ourselves with off-the-shelf hardware.

Besides the cyberpunk aesthetic, the main attraction here is the UNIHIKER Linux board running the show. After that, it’s probably a tie between that giant mystery knob and the super-cool GUI made with Tkinter.

We also like the fact that there are two displays: the smaller one on the SSD1306 OLED handles the less exciting stuff like the volume level and the current time, so that the main UNIHIKER screen can have all the equalizer/cyberpunk fun.

Speaking of, this user-friendly GUI shows play/stop buttons and next buttons, but it looks like there’s no easy way to get to the previous track. To each their own, we suppose. Everything is enclosed in a brick-like 3D-printed enclosure that mimics early Walkmans with orange foam headphones.

If you want an updated Walkman with keyboard switches (who wouldn’t?), check this out.

A simple yet intriguing idea is worth sharing, even if it wasn’t a flawless success: it can inspire others. [Richard]’s experiment with a motion-powered AirTag fits this bill. Starting with our call for simple projects, [Richard] came up with a circuit that selectively powers an AirTag based on movement. His concept was to use an inertial measurement unit (IMU) and a microcontroller to switch the AirTag on only when it’s on the move, creating a stealthy and battery-efficient tracker.

The setup is minimal: an ESP32 microcontroller, an MPU-6050 IMU, a transistor, and some breadboard magic. [Richard] demonstrates the concept using a clone AirTag due to concerns about soldering leads onto a genuine one. The breadboard-powered clone chirps to life when movement is detected, but that’s where challenges arise. For one, Apple AirTags are notoriously picky about batteries—a lesson learned when Duracell’s bitter coating blocks functionality. And while the prototype works initially, an unfortunate soldering mishap sadly sends the experiment off the rails.

Despite the setbacks, this project may spark a discussion on the possibilities of DIY digital camouflage for Bluetooth trackers. By powering up only when needed, such a device avoids constant broadcasting, making it harder to detect or block. Whether for tracking stolen vehicles or low-profile uses, it’s a concept rich with potential. We talked about this back in 2022, and there’s an interesting 38C3 talk that sheds quite some light on the broadcasting protocols and standards.

Header AirTag: Apple, Public domain, via Wikimedia Commons

The ESP32 series of microcontrollers have been with us for quite a few years now and appeared in both Tensilica and RISC-V variants, both of which deliver an inexpensive and powerful device. It’s thus shown up in quite a few handheld computers, whether they be conference badges or standalone devices, and this is definitely a field in which these chips have more to give. We’re pleased then to see this e-ink PDA from [ashtf8], which we think raises the bar on this type of device.

At its heart is an ESP32-S3, on the back side of a QWERTY keyboard PCB, and for a display it has an e-ink screen. To get over the annoying e-ink refresh when typing text it uses a hybrid of e-ink and OLED, with a small OLED holding the current line which can be periodically sent to the e-ink. Perhaps the nicest thing about the hardware though is the clear resin printed clamshell case, and a hand-cast silicone membrane for the keyboard. That has always been a part considered difficult to produce, and here he is making one from scratch. Take a look at the video below the break.

Software-wise it has a range of apps with more promised, but even as it stands it looks useful enough to work with. If that’s not enough, then perhaps an ESP32 operating system would help.

Raspberry Pi’s new microcontroller, the RP2350, has a small section of memory that is meant for storing secrets. It’s protected by anti-glitching and other countermeasures, and the Raspberries wanted to test it. So this summer, they gave them out, pre-programmed with a secret string, as part of the badge for DEFCON attendees. The results of the cracking efforts are in, and it’s fair to say that the hackers have won.

First place went to [Aedan Cullen], who also gave a great talk about how he did it at 38C3. One of the coolest features of the RP2350, from a hacker perspective, is that it has dual ARM and dual RISC-V cores onboard, and they can be swapped out by multiplexers. The security module has a critical register that has disable bits for both of these processors, but it turns out that the ARM disable bits have priority. When [Aedan] glitched the security module just right, it disabled the ARM cores but left the RISC-V cores running in the secure context, with full debug(!), and the game was over. As of yet, there is no mitigation for this one, because it’s baked into the secure boot module’s silicon.

[Marius Muench] managed to pre-load malicious code into RAM and glitch a reboot-out-of-secure-mode on the USB module. This one is possibly fixable by checking other reboot flags. [Kévin Courdesses] has a sweet laser fault-injection rig that’s based on the 3D-printable OpenFlexure Delta Stage, which we’ve seen used for microscopy purposes, but here he’s bypassing the anti-glitching circuitry by exposing the die and hitting it hard with photons.

Finally, [Andrew Zonenberg] and a team from IOActive went at the RP2350 with a focused ion beam and just read the memory, or at least the pairwise-OR of neighboring bits. Pulling this attack off isn’t cheap, and it’s a more general property of all anti-fuse memory cells that they can be read out this way. Chalk this up as a mostly-win for the offense in this case.

If you want to read up on voltage glitching attacks yourself, and we promise we won’t judge, [Matthew Alt] has a great writeup on the topic. And ironically enough, one of his tools of choice is [Colin O’Flynn]’s RP2040-based Chip Shouter EMP glitcher, which he showed us how to make and use in this 2021 Remoticon talk.

[Chad Burrow] decided to take on a noble task—building a “retro” style computer and video game console. Only, this one is built using somewhat modern hardware—relying on the grunt of the PIC32MZ2048EFH144 to get the job done. Meet the Acolyte Hand PIC’d 32.

It’s name might be a mouthful, but that chip can pull off some great feats! With a clock speed of 200 MHz, it’s not  short on processing power, though RAM and flash storage are somewhat limited at just 512 KB and 2MB respectively. [Chad] was able to leverage those constraints to get a VGA output working at a resolutions up to 800 x 600, with up to 65,000 colors—though 256 colors is more practical due to memory concerns. The Acolyte Hand also rocks two 8-bit audio channels. It has a pair of Genesis-compatible controller ports as well as PS/2 and USB for keyboards and mice, along with more modern Xbox 360 controllers.

[Chad] cooked up some software to put it through its paces, too. It’s got a Tetris clone on board, and can also run Game Boy games at full speed via the Peanut-GB emulator. That provides for a pretty rich game library, though [Chad] notes he plans to develop more native video games for his system to demo at his local college. Design files are on Github for the curious.

This project is a great example of just how powerful modern microcontrollers have become. Once upon a time, just driving a simple black-and-white graphical LCD might have taken some real effort, but today, there are pixels and clock cycles to spare in projects like these. Truly a wonderous world we live in!

Doing the rounds this week is a new operating system for ESP32 microcontrollers, it’s called Tactility, and it comes from [Ken Van Hoeylandt]. It provides a basic operating system level with the ability to run apps from an SD card, and it has the choice of a headless version or an LVGL-based touch UI.

Supported devices so far are some Lillygo and M5Stack boards, with intriguingly, support in the works for the Cheap Yellow Display board that’s caught some attention recently. The term “ESP32” is now a wide one encompassing Tensilica and RISC-V cores and a range of capabilities, so time will tell how flexible it is for all branches of the family.

We find this OS to be interesting, both in its own right and because it joins at least two others trying to do the same thing. There’s [Sprite_TM]’s PocketSprite mini console, and the operating system used by the series of Netherlands hacker camp badges,  We’ll be trying to get a device running it, in order to give you a look at whether it’s suitable for your projects. If it runs well on the cheaper hardware, it could be a winner!

The LM3914 LED bar graph driver was an amazing chip back in the day. Along with the LM3915, its logarithmic cousin, these chips gave a modern look to projects, allowing dancing LEDs to stand in for a moving coil meter. But time wore on and the chips got harder to find and even harder to fit into modern projects, what with their giant DIP-18 footprint. What’s to be done when a project cries out for bouncing LEDs? Simple — get a RISC-V microcontroller and roll your own LED audio level meter.

In fairness, “simple” isn’t exactly what comes to mind while reading [svofski]’s write-up of this project. It’s part of a larger build, a wavetable synth called “Pétomane Ringard” which just screams out for lots of blinky LEDs. [svofski] managed to squeeze 20 small SMD LEDs onto the board along with a CH32V003 microcontroller. The LEDs are charlieplexed, using five of the RISC-V chip’s six available GPIO lines, leaving one for the ADC input. That caused a bit of trouble with programming, since one of those pins is needed to connect to the programmer. This actually bricked the chip, thankfully only temporarily since there’s a way to glitch the chip back to life, but only after pulling it out of the circuit. [svofski] recommends adding a five-second delay loop to the initialization routine to allow time to recover if the microcontroller gets into an unprogrammable state. Good tip.

As for results, we think the level meter looks fantastic. [svofski] went for automated assembly of the 0402 LEDs, so the strip is straight and evenly spaced. The meter seems to be quite responsive, and the peak hold feature is a nice touch. It’s nice to know there’s a reasonable substitute for the LM391x chips, especially now that all the hard work has been done.

Bluetooth is a good way to connect devices that are near each other. However, it can drain batteries which is one reason Bluetooth Low Energy — BLE — exists. [Drmph] shows how easy it is to deploy BLE to make, in this case, a doorbell. He even shows how you can refit an existing doorbell to use the newer technology.

Like many projects, this one started out of necessity. The existing wireless doorbell failed, but it was difficult to find a new unit with good review. Cheap doorbells tend to ring spuriously due to interference. BLE, of course, doesn’t have that problem. Common BLE modules make up the bulk of the project. It is easy enough to add your own style to the doorbell like a voice announcement or musical playback. The transmitter is little more than a switch, the module, a coin cell, and an LED.

It is, of course, possible to have a single receiver read multiple doorbells. For example, a front door and back door with different tones. The post shows how to make a remote monitor, too, if you need the bell to ring beyond the range of BLE.

A fun, simple, and useful project. Of course, the cool doorbells now have video. Just be careful not to get carried away.