You Can Always Use An ATtiny Instead Of A 555

December 15, 2021 by Jenny List 62 Comments

It’s a constant of writing for Hackaday, that whenever a project appears using a 555 timer, someone will say “You could have used a microcontroller to do that!”. It’s something that [Shranav Palakurthi] has approached with the ATTiny555, a project that emulates an entire 555 by making clever use of the humble and ubiquitous microcontroller chip. We’ve all been guilty of it at some time, but now at last the ATTiny85 enthusiasts have conclusive proof that their favourite piece of cheap silicon can prove its mettle.

The full details of the ingenious 555 replacement can be found in its GitHub repository, and for those willing to take the plunge it’s as simple as adding a resistor and updating the firmware. It’s not the perfect 555 replacement with its imperfect analogue performance and swapped reset and ground pins, but it does however bring the advantage of a lower supply voltage.

You can see the device in action in the YouTube video below the break, but meanwhile rejoice that finally there’s a way to replace all those unnecessary 555s with your favourite inexpensive 8-pin chip!

While we’re on the subject of the 555, don’t forget we’re running our 555 contest again.

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A scaled down version of a pedestrian crossing signal

Don’t Walk Past This 3D Printed Pedestrian Crossing Light

December 1, 2021 by Chris Wilkinson 9 Comments

There’s just something so pleasing about scaled-down electronic replicas, and this adorable 3D printed pedestrian crossing light by [sjm4306] is no exception.

Although a little smaller than its real-world counterpart, the bright yellow housing and illuminated indicators on this pedestrian lamp are instantly recognizable due to their ubiquitous use throughout the United States. The handful of printed parts are held together using friction alone, which makes assembly a literal snap. The ‘safety grill’ with its many angles ended up being one of the most tedious parts of the build process, but the effort was definitely justified, as it just wouldn’t look right without it.

A suitably minuscule ATtiny85 drives a pair of LED strips that effectively mimic the familiar symbols for ‘Walk’ and ‘Don’t Walk’. [sjm4306] has designed the board and case in such a way to accommodate a variety of options. For example, there’s just enough room to squeeze in a thin battery, should you want to power this contraption on-the-go. If you don’t have an ATtiny85 on hand, the board also supports an ATmega328p or even an ESP8266.

All the build details are available over on Hackaday.io. While it’s billed as a ‘night light’, we think this could be an awesome platform for an office toy, similar to this office status light project. Or if you’ve somehow already got your hands on a full-size pedestrian lamp, why not hook it up to the Internet?

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A scrolling name badge that uses LED matrices.

Scrolling Name Badge Is Sure To Break The Ice

November 29, 2021 by Kristina Panos 2 Comments

Most makerspaces and hackerspaces have one night per week or month where the ‘space is open to the public in order to entice new people into joining up. Whereas most members just write their name in Sharpie on a piece of masking tape, [Madison] wanted to do something extra. And what better way to get people interested in your ‘space than by wearing something useful that came out of it?

The badge runs on an ATtiny45 and uses three 8×8 ultra-bright LED matrices for scrolling [Madison]’s name. It’s powered by a tiny LiPo battery that is boosted to 5 V. This build really shows off a number of skills, especially design. We love the look of this badge, from the pink silkscreen to the the typography. One of the hardest things about design is finding fonts that work well together, and we think [Madison] chose wisely. Be sure to check it out in action after the break.

Custom name badges are a great way to start conversations no matter where you go. Here’s one that uses EL wire and LEDs that light up in sequence for an animated effect.

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Tiny Talisman Warns Wearer About UV Exposure

November 14, 2021 by Dan Maloney 14 Comments

Given how important our Sun is, our ancestors can be forgiven for seeing it as a god. And even now that we know what it actually is and how it works, it’s not much of a reach to think that the Sun pours forth evil spirits that can visit disease and death on those who bask too long in its rays. So an amulet of protection against the evil UV rays is a totally reasonable project, right?

As is often the case with [mitxela]’s projects, especially the more bedazzled ones, this one is approximately equal parts electronics and fine metalworking. The bulk of the video below focuses on the metalwork, which is pretty fascinating stuff. The case for the amulet was made from brass and sized to fit a CR2032 coin cell. The back of the amulet is threaded to act as a battery cover, and some fancy lathe work was needed there. The case was also electroplated in gold to prevent tarnishing, and lends a nice look when paired up with the black solder mask of the PCB.

On the electronics side, [mitxela] took pains to keep battery drain as low as possible and to make the best use of the available space, choosing an ATtiny84 to support a TTP223 capacitive sensing chip and a VEML6075 UV sensor. The touch sensor allows the wearer to wake the amulet and cycles through UV modes, which [mitxela] learned were not exactly what the sensor datasheet said they were. This required a few software hacks, but in the end, the amulet does a decent job of reporting the UV index and looks fantastic while doing it.

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‘Tiny Wake-Up Light Is Hugely Bright

November 6, 2021 by Kristina Panos 26 Comments

Let’s face it — waking up is rough no matter what time of year it is. But the darkness of fall and winter makes it so much worse. In the past, [Maarten] has used music with increasing volume, but depending on the setup, it can be dodgy if you want to hear a different song each day and don’t have all your files volume-leveled.

Wake Up Bright is the latest in a line of wake-up widgets [Maarten] has made to help rouse them in the morning. Their write-up covers all ideas they’ve had on the subject over the years, as well as the electronics, firmware, debugging, and all the upgrades made after using it for awhile.

Slowly brightening an LED doesn’t have to be difficult or expensive. [Maarten] originally used an Atmel 90S2313 AVR and later upgraded to an ATtiny 2313, which was easy because the two are pin-compatible. The 2313 outputs PWM, which duty-cycles the LED to create a nice fade-in of white light that is way more gentle than that classic 1980s alarm clock buzz-beep.

Over time, this project went from one IKEA enclosure to another. We really like the newer one, which looks like it was designed for people to hack into a wake-up light.

Our eyes perceive brightness increases logarithmically, but PWM is linear. We can get around this by multiplying the PWM value by some factor every so often, but the problem is that this AVR never learned its multiplication tables. So how, then? [Maarten]’s answer is byte shifting using a 16-bit register — one byte for PWM, and the other as a scratch pad to do logarithmic math. [Maarten] multiplies the 16-bit register by 1/256 every couple of seconds, which results in a logarithmic increase of brightness. It’s calculated for a 15-minute sunrise, which required some experimentation to get right.

Whereas [Maarten] started with a 3 W RGB LED, the current version has three 10 W LEDs and uses a power supply from an old monitor. Daylight Saving Time is coming to an end in the US, and it’s gonna get worse quickly. Lucky for you, this project is completely open source down to the firmware.

You think that 1980s alarm clock buzz-beep is bad? How about some repeated slaps to the face to wake up?

Tiny pomodoro timer starts as soon as you plug it in.

Cherry Pomodoro Timer Forces You To Follow

October 31, 2021 by Kristina Panos 13 Comments

If you have trouble staying focused and getting work done, the Pomodoro Technique of working in 25-minute intervals with 5-minute breaks is pretty hard to beat. The only problem is that it requires a lot of input from the user, and all that timer-setting can get in the way of actually getting down to business. The absolute worst is when you find yourself working hard, but see that forgot to set the damn timer (ask us how we know). In essence, the tomato itself can only do so much — you have to actually use it and honor the timer, put in the work, and believe in the system.

But what if you didn’t have to do as much? With [Erfan Sn]’s design, all you have to do is plug it in to a USB port and the countdown starts automatically. Not only does this Pomodoro timer force you to get with the program, it also makes you take breaks from the screen by putting the computer into sleep mode when the 25 minutes (or whatever time you set in the software) are up. This thing even keeps track of your Pomodoro count.

At the heart of this build is the Digispark ATtiny85 dev board, which has a handy onboard USB plug. It can be built with or without the OLED screen, which is good if you are easily distracted by the timer itself. This cherry tomato only costs about $10 to make, it’s tiny, and you can take it anywhere.

As you will see in the gifs on GitHub, [Erfan Sn] has it plugged into a female USB-A to male USB-C, which is probably better for the computer long-term, what with all the plugging and unplugging. When we make ours, we’ll probably plug it into a hub that has power switches for each port.

If all of this sounds like too much work, check out this build that senses whether or not you’re in the chair.

Two hands on a book labeled "hardware crowdfunding"

Successfully Crowdfunded Hardware: Everything Behind The Scenes

September 12, 2021 by Donald Papp 5 Comments

Crowdfunding hardware has its own unique challenges, and [Uri Shaked] wrote a fascinating report that goes into excellent detail about his experience bringing a crowdfunded hardware project to life.

[Uri]’s project was The Skull CTF, an electronic hardware puzzle that came in the shape of a PCB skull, and his detailed look behind the scenes covers just about every angle, from original concept to final wrap-up, along with his thoughts and feedback at every stage. His project reached its funding goal, got manufactured and shipped, and in the end was a success.

[Uri] started with a working project, but beyond that was virtually a complete novice when it came to crowdfunding. He eventually settled on using Crowd Supply to make his idea happen, and his writeup explains in great detail every stage of that process, including dollar amounts. What’s great to see is that not only does [Uri] explain the steps and decisions involved, but explains the research that went into each, and how he feels each of them ended up working out.

The entire thing is worth a read, but [Uri] summarizes the experience of crowdfunding a hardware project thus: an excellent way to test out the demand for an idea and bring a product into existence, but be aware that unless a project is a runaway success it probably won’t be much of an income generator at that stage. It was a great learning experience, but involved a lot of time and effort on his part as well.

[Uri] really knows his stuff, and considering his skill at hunting down pesky bugs, it’s probably no surprise that this wasn’t his first hardware puzzle.