2026-02-08 17:00:15
The Core Duo processor from Intel may not have been the first multi-core processor available to consumers, but it was arguably the one that brought it to the masses. Unfortunately, the first Core Duo chips were limited to 32-bit at a time when the industry was shifting toward 64-bit. The Core 2 Duo eventually filled this gap, and [dosdude1] recently completed an upgrade to a Macbook Pro that he had always wanted to do by replacing the Core Duo processor it had originally with a Core 2 Duo from a dead motherboard.
The upgrade does require a bit more tooling than many of us may have access too, but the process isn’t completely out of reach, and centers around desoldering the donor processor and making sure the new motherboard gets heated appropriately when removing the old chip and installing the new one. These motherboards had an issue of moisture ingress which adds a pre-heating step that had been the cause of [dosdude1]’s failures in previous attempts. But with the new chip cleaned up, prepared with solder balls, and placed on the new motherboard it was ready to solder into its new home.
Upon booting the upgraded machine, the only hiccup seemed to be that the system isn’t correctly identifying the clock speed. A firmware update solved this problem, though, and the machine is ready for use. For those who may be wondering why one would do something like this given the obsolete hardware, we’d note that beyond the satisfaction of doing it for its own sake these older Macbooks are among the few machines that can run free and open firmware, and also that Macbooks that are a decade or older can easily make excellent Linux machines even given their hardware limitations.
2026-02-08 14:00:45
Over on YouTube [Andrew Neal] has a Function Generator Build for Beginners.
As beginner videos go this one is fairly comprehensive. [Andrew] shows us how to build a square-wave generator on a breadboard using a 555 timer, explaining how its internal flip-flop is controlled by added resistance and capacitance to become a relaxation oscillator. He shows how to couple a potentiometer to vary the frequency.
He then adds an integrator built from a TL082 dual op amp to convert the circuit to a triangle-wave generator, using its second op amp to build a binary inverter. He notes that a binary inverter is usually implemented with a comparator, but he uses the op amp because it was spare and could be put to good use. Again, potentiometers are added for frequency control, in this case a 1 MΩ pot for coarse control and a 10 kΩ pot for fine control. He ends with a challenge to the viewer: how can this circuit be modified to be a sine-wave generator? Sound off in the comments if you have some ideas!
If you’re interested to know more about function generators check out A Function Generator From The Past and Budget Brilliance: DHO800 Function Generator.
2026-02-08 11:00:04
Pomodoro timers are a simple productivity tool. They help you work in dedicated chunks of time, usually 25 minutes in a sitting, before taking a short break and then beginning again. [Clovis Fritzen] built just such a timer of his own, and added a few bonus features to fill out its functionality.
The timer is based around the popular ESP32-S2 microcontroller, which has the benefit of onboard WiFi connectivity. This allows the project to query the Internet for things like time and date updates via NTP, as well as weather conditions, and the value of the Brazilian Real versus the American dollar. The microcontroller is paired with an SHT21 sensor for displaying temperature and humidity in the immediate environment, and an e-paper display for showing timer status and other relevant information. A button on top of the device allows cycling between 15, 30, 45, and 60 minute Pomodoro cycles, and there’s a buzzer to audibly call time. It’s all wrapped up in a cardboard housing that somehow pairs rather nicely with the e-paper display aesthetic.
If Pomodoro is your chosen method of productivity hacking, a project like this could suit you very well. We’ve featured a few similar builds before, too.
2026-02-08 08:00:06
Sometimes you have this project idea in your mind that seems so simple and straightforward, and which feels just so right that you have to roll with it. Then, years later you stumble across the sad remnants of the tearful saga and the dismal failure that it portrays. Do you put it away again, like an unpleasant memory, or write it up in an article, as a tearful confession of past sins? After some coaxing by a friend, [Alessandro] worked up the courage to detail how he set about making a hardware-only password keeper, and why it failed.
The idea was so simple: the device would pretend to be a keyboard and type the passwords for you. This is not that unusual, as hardware devices like the Mooltipass do something similar. Even better, it’d be constructed only out of parts lying around, including an ATtiny85 and an HD44780 display, with bit-banged USB connectivity.
Overcoming the challenge of driving the LC display with one pin on the MCU required adding a 74HC595 demultiplexer and careful timing, which sort of worked when the stars aligned just right. Good enough, but what about adding new passwords?
This is where things quickly skidded off the tracks in the most slapstick way possible, as [Alessandro] solved the problem of USB keyboard HID devices being technically ‘output-only’, by abusing the indicator statuses for Caps Lock, Num Lock, and Scroll Lock. By driving these from the host PC in just the right way you can use them as a sort of serial protocol. This incidentally turned out to be the most reliable part of the project.
Where the project finally tripped and fell down the proverbial flight of stairs was when it came to making the bit-banged USB work reliably. As it turns out, USB is very unforgiving with its timing unlike PS/2, making for an infuriating user experience. After tossing the prototype hardware into a box, this is where the project gathered dust for the past years.
If you want to give it a try yourself, maybe using an MCU that has more GPIO and perhaps even a USB hardware peripheral like the STM32F103, ESP32-S3 or something fruit-flavored, you can take a gander at the project files in the GitHub repository.
We’re always happy to see projects that (ab)use the Lock status indicators, it’s always been one of our favorite keyboard hacks.
2026-02-08 05:00:34
If you want to play with the coolest kids on the block when it comes to photography, you have to shoot film. Or so say the people who shoot film, anyway. It is very true though that the chemical medium has its own quirks and needs a bit of effort in a way digital cameras don’t, so it can be a lot of fun to play with.
It’s expensive though — film ain’t cheap, and if you don’t develop yourself there’s an extra load of cash. What if you could get more photos on a roll? It’s something [Japhy Riddle] took to extremes, creating a fifth-frame 35mm camera in which each shot is a fifth the size of the full frame.
Standard 35mm still film has a 24x36mm frame, in modern terms not far off the size of a full-size SD card. A standard roll of film gives you 36 exposures. There are half-frame cameras that split that frame vertically to give 72 exposures, but what he’s done is make a quarter-frame camera.
It’s a simple enough hack, electrical tape masking the frame except for a vertical strip in the middle, but perhaps the most interesting part is how he winds the film along by a quarter frame. 35mm cameras have a take-up reel, you wind the film out of the cartridge bit by bit into it with each shot, and then rewind the whole lot back into the cartridge at the end. He’s wound the film into the take-up reel and it winding it back a quarter frame at a time using the rewind handle, for which we are guessing he also needs a means to cock the shutter that doesn’t involve the frame advance lever.
We like the hack, though we would be worried about adhesive tape anywhere near the shutter blind on an SLR camera. It delivers glorious widescreen at the cost of a bit of resolution, but as an experimental camera it’s in the best tradition. This is one to hack into an unloved 1970s snapshot camera for the Shitty Camera Challenge!
2026-02-08 02:00:55
Poorly designed PCBs and enclosures that slowly cook the electrolytic capacitors within are a common failure scenario in general, but they seem especially prevalent in so-called Internet-of-Things devices. The SwitchBot Plug Mini that [Denki Otaku] took a look at after many reports of them failing is one such example.
These Mini Plugs are ‘smart’ plugs that fit into a regular outlet and then allow you to control them remotely, albeit not integrated into a wall or such like the Shelly 2.5 smart relay that also began dying in droves. Yet whereas with the Shelly relays this always seemed to take a few years to show up, generally in the form of WiFi connectivity issues, these SwitchBot plugs sometimes failed within weeks or start constantly switching the relay on and off.
After SwitchBot started an exchange program for these plugs, [Denki Otaku] decided to examine these failed devices from affected users. Inside a dead unit the secondary side’s 680 µF capacitor was clearly bulging and had cooked off its electrolyte as a teardown of a dead capacitor confirmed. After replacing this one capacitor a formerly unresponsive plug sprung back to life.
This failed capacitor is important as it serves as the buffer for the 3.3 V rail, which otherwise sags below the operational range of the microcontroller during power-hungry WiFi operations, causing it to reset. As for the question of why this failure happened, there are two possibilities: one involves the B- or C-tier capacitor – for which no datasheet could be found – being unsuitable for dealing with the ripple current it was exposed to, the other being the high temperatures in that section of the PCB.
As a thermal image of the working PCB shows, the voltage regulator and switching circuitry present on the PCB – right below where the failed capacitor is located – reach a temperature of up to about 50°C, without taking into account the sealed enclosure that the PCB is located in.
The WiFi module that is located next to the capacitor and sticking up vertically from the PCB also reached a similar high temperature, making sure to bake the affected capacitor from below and the side. Even in open air the capacitor reached a temperature of about 43°C.
While a higher-quality capacitor will very likely cope with ripple current better, ultimately it’s pretty much just an unnecessarily stressful environment for electrolytic capacitors. While investigating two newer batches of these Plug Minis that are not subject to recall, the older unit still had the same flawed capacitor, while the new unit had replaced it with what looks like a polymer capacitor with the same ratings.
Interestingly, one of the failed plugs that [Denki Otaku] got sent did use one of these polymer capacitors, but appears to have another fault that wasn’t further investigated. Either way, the use of a polymer capacitor seems to help with the longevity to get it at least past the warranty period, but without a redesign these units seem doomed to fail due to rapid capacitor aging.
