Swap The Clock Chip On The Mac SE/30 With An ATTiny85

January 13, 2023 by Tom Nardi 20 Comments

As [Phil Greenland] explains in the first part of his excellent write-up, the lithium battery used to keep the real-time clock (RTC) going on the Macintosh SE/30 has a nasty habit of exploding and leaking its corrosive innards all over the board. Looking to both repair the damage on a system that’s already had a battery popped and avoid the issue altogether on pristine boards, he started researching how he could replace the battery with something a bit more modern.

It turns out, the ATtiny85 is pin-compatible with the Mac’s original RTC chip, and indeed, [Andrew Makousky] had already written some code that would allow the microcontroller to emulate it. This is actually a bit more complex than you might realize, as the original RTC chip was doing double-duty: it also held 256 bytes of parameter random access memory (PRAM), which is where the machine stored assorted bits of info like which drive to boot from and the mouse cursor speed.

But after getting the mod installed, the computer refused to start. It turns out the project targeted earlier machines like the Macintosh Plus and SE, and not his higher-performance SE/30. Thanks to community resources like this KiCad recreation of the SE/30’s motherboard, contemporary technical documents, and his trusty logic analyzer, [Phil] was able to figure out that the timing was off — the code was simply struggling to respond to the faster machine. Continue reading “Swap The Clock Chip On The Mac SE/30 With An ATTiny85” →

Mouse Whisperer Keeps You Working, Even When You Need A Break

December 19, 2022 by Dan Maloney 144 Comments

When life hands you lemons, you make lemonade, right? What about when life hands you annoyingly intrusive work-from-home policies that require you to physically stay at your computer even though you really, REALLY need to go to the bathroom, but can’t be trusted to act like a responsible adult who won’t get diverted by TV or the fridge on the way back? In that case, you build something like the Mouse Whisperer — because malicious compliance is the best kind of compliance.

To be fair, [andrey.malyshenko] does list other plausible use cases for what amounts to an automatic mouse wiggler. Like many of us, [andrey] isn’t a fan of logging back in from screen locks, and recognizes that not absolutely every minute of work requires staring at one’s screen. There’s also the need for bio-breaks, of course, and the Mouse Whisperer is designed to accommodate these use cases and more.

The design is quite compact, occupying barely more space than a wireless mouse dongle. Plugged into a USB port, the ATtiny85 mostly sits idle, waiting to detect the touch of a finger on an exposed pad via a TTP223. The dongle then goes into a routine that traces lazy circles with the mouse pointer, plus flashes an RGB LEB on the board, because blinkenlights are cool. The mouse wiggling continues until you come back from your Very Important Business and touch the pad again.

Now, if anyone is actually monitoring you remotely, the circling mouse pointer is going to look a wee bit sus. Fear not, though — the code uses a *.h file to define the circle, so other patterns should be possible. Either way, the Mouse Whisperer is a nice solution, and it’s considerably more compact and integrated than some of the alternatives we’ve seen.

Circular Binary Clock Uses The Power To Tell Time

November 25, 2022 by Kristina Panos 5 Comments

Should a clock be round? Depends on the style of clock, we suppose. After all, we wouldn’t expect to see a digital clock with a round readout just for fun. But a binary clock — that’s another animal altogether. Whereas [JohnThinger] made just a few weeks back a linear binary clock using an RGB LED strip and an ATtiny, he decided it would look much better in the round.

Before you go decrying the fact that there are numbers other than 1 and 0 on the thing, those are simply the power of two by which one must multiply to get the time. And naturally, it’s done in three phases, with the yellow-green numbers representing the seconds, the pink-red representing minutes, and the blue standing for the current hour. No, the point is not to make life easier. But it’s a good-looking clock, no?

Just as before, an ATtiny85 is the brain, with an RTC chip and an oscillator to keep time. But now, the display involves negative space 3D-printed numbers and an RGB LED ring. Be sure to check it out after the break.

Continue reading “Circular Binary Clock Uses The Power To Tell Time” →

Mini Ultrasonic Levitation Kit Is An Exercise In Sound Minimalist Design

November 6, 2022 by Abe Connelly 20 Comments

For those that haven’t heard, ultrasonic levitation is a process by which two or more ultrasonic transducers are set opposite to each other and excited in such a way as to create a standing wave between them. The sound is, as the name implies, ultrasonic — so outside the range of human hearing — but strong enough so that the small, light objects can be positioned and held fixed in mid-air where there’s a pressure minimum in the standing wave. [Olimex] has created a small ultrasonic levitation kit that exemplifies this phenomena.

The kit itself is made using through-hole components, with an ATTiny85 as the core microcontroller to drive two TCT40-16T ultrasonic speakers, and a MAX232 ~~to provide a USB interface~~ drives the transducers (thanks to the folks in the comments for the correction). Two slotted rectangular PCB pieces that solder connect to the main board, provide a base so that the device stands upright when assembled. The whole device is powered through the USB connection, and the ultrasonic speakers output in the 40KHz range providing enough power to levitate small Styrofoam balls.

The project is, by design, an exercise in minimalism, providing a kit that can be easily assembled, and providing code that can be easily flashed onto the device, examined and modified. All the design files, including the bill of materials, KiCAD schematics, and source code are provided under an open source hardware license to allow for anyone wanting to know how such a project works, or to extend it themselves, ample opportunity. [Olimex] also has the kit for sale for those not wanting to source boards and parts themselves.

We’ve featured ultrasonic levitation devices before, from bare bones system driven by a NE555 to massive phased arrays.

A 3d printed ghost next to the base of an LED tea light that has 4 LEDs poking out and the IR receiver port and micro-USB connector showing.

A Cold Light To Warm Your Heart

October 9, 2022 by Abe Connelly 1 Comment

Halloween is coming fast and what better way to add to your Halloween ornamentation than [Wagiminator]’s cute NeoCandle tea light simulator.

[Wagiminator] has modified a 3D printed ghost along with extending [Mark Sherman]’s light simulation code to create a cute light that’s perfect for the holiday season. The NeoCandle uses an ATtiny85 chip to power four WS2812 NeoPixel jelly bean LEDs. The device has an infrared (IR) receiver to be able to control it from a remote that speaks the NEC protocol. There is a light sensor that allows the unit to dim when it detects ambient light and the whole unit is powered off of a micro-USB connection.

The ATtiny85 have limited program flash and [Wagiminator] packs in a lot of functionality in such a small package, squeezing in a bit-banging NeoPixel driver in only 18 bytes of flash that can push out a transfer rate 762 kpbs to update the LEDs. The pseudo-random number uses a Galois linear feedback shift register and comes in at 86 bytes of flash, with the IR receiver implementation code being the largest using 234 bytes of flash. The ATtiny85 itself has 8 KB of flash memory so maybe it’s possible to push [Waginminator]’s code to even more restrictive Atmel devices in the ATtiny family.

With microcontrollers and LEDs becoming so cheap and ubiquitous, making realistic flames with them is becoming accessible, as we’ve seen with previous projects on electronic candles.

Continue reading “A Cold Light To Warm Your Heart” →

Sleep Posture Monitor Warns You Away From Dangerous Positions

August 28, 2022 by Dan Maloney 1 Comment

Age, we’re told, is just a number, but that number seems to be the ever-increasing count of injuries of a ridiculous nature. Where once the younger version of us could jump from a moving car or fall out of a tree with just a few scrapes to show for the effort, add a few dozen trips around the sun and you find that just “sleeping funny” can put you out of service for a week.

Keen to avoid such woes, [Elite Worm] came up with this sleep posture alarm to watch for nocturnal transgressions, having noticed that switching to a face-down sleeping position puts a kink in his neck. He first considered using simple mechanical tilt switches to detect unconscious excursions from supine to prone. But rather than be locked into a single posture, he decided to go with an accelerometer instead. The IMU and an ATtiny85 live on a custom PCB along with a small vibrating motor, which allows for more discrete alerts than a buzzer or beeper would.

Placed in a 3D printed enclosure and clipped to his shorts, the wearable is ready to go. The microcontroller wakes up every eight seconds to check his position, sounding the alarm if he’s drifting into painful territory. [Elite] did some power analysis on the device, and while there’s room for improvement, the current estimated 18 days between charging isn’t too shabby. The video below has all the details; hopefully, design files and code will show up on his GitHub soon.

Considering that most of us spend a third of our life sleeping, it’s little wonder hackers have attacked sleep problems with gusto. From watching your brainwaves to AI-generated nonsense ASMR, there’s plenty of hacking fodder once your head hits the pillow.

Continue reading “Sleep Posture Monitor Warns You Away From Dangerous Positions” →

A Customizable Macropad To Make Anyone’s Tail Wag

July 28, 2022 by Kristina Panos 4 Comments

[Gili Yankovitch] has always wanted some kind of macro keypad for all those boss-slaying combos he keeps up the sleeve of his wizard robe while playing WoW. Seventeen years later, he finally threw down the gauntlet and built one. But really, this is an understatement, because Paws is kind of the customizable macropad to end all customizable macropads.

This thing is completely bespoke, and yet cookie cutter at the same time — but we mean that in the best possible way. Paws can be made in any shape or form, and quite easily. How is this even possible, you ask? Well, every single key has its own microcontroller.

Yep, each key has an ATtiny85 and a cute little ribbon cable, and these form a token ring network that talks to an Arduino, which provides the keyboard interface to the computer. To make things even easier, [Gili] built a simple programming UI that automatically recognizes the configuration and number of keys, and lets the user choose the most important bit of all — the color of the LED.

[Gili] wanted to combine all the skills he’s learned since the worst timeline started in early 2020 — embedded software, CAD, electronics, and PCB design. We’d like to add networking to that list, especially since he figured out a nice workaround for the slowness of I²C and the limitations of communication between the ‘tiny85s and the Arduino. Though [Gili] may have started out with a tall order, he definitely filled it. Want to get your paws on the design files? Just claw your way over to GitHub.

If your customization interests lie more toward what program is in focus, be sure to check out Keybon, which was one of the many awesome winners of our Odd Inputs and Peculiar Peripherals contest.