Calendar Printer Makes You A Hard Copy On The Daily

We’re blessed to have cloud-based calendars that store all the relevant data on our hyper-busy lives for easy access anywhere and everywhere. However, sometimes a hard copy is nice for when you’re tired of looking at screens. In this vein, [lokthelok] produced a compact device that prints out your schedule on the daily.

The device uses an ESP32 to connect to WiFi, and then query Google Apps for a given user’s calendar details on a daily basis. After grabbing the data, it’s fed out to a thermal printer connected over serial at 9600 baud. As a twist, [lokthelok] has produced two versions of firmware for the project. The master version simply scrapes calendar data and outputs it neatly. The Useless version goes further, jumbling up appointments and printing them out of order. If you’ve got nothing on for the day, it will instead spool out the remainder of the thermal paper on the roll.

It’s a build that would make a handsome desk toy, though we suspect tossing out each day’s calendar could become tiresome after a while. Alternatively, consider a clock that highlights your upcoming events for you. Video after the break.

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E-Ink Calendar Paves A Path For All

[Martin Fasani] has set out to build a beautiful low power E-Ink Calendar he can hang on his wall. But perhaps more importantly, the work he has done makes it easier for everyone in the future to have a e-ink display. Many battery-powered e-ink projects connect to some server, download a bitmap image, display the new image, and then go into a deep sleep power mode. [Martin’s] project is no different, but it uses a handy microservice that does the conversion and rendering for you.

The firmware for this ESP32/ESP32S2 based calendar is open sourced on GitHub, with a version based on the Arduino framework as well as the native ESP-IDF framework. One particularly fantastic part of the firmware is a C++ component called CalEPD that drives e-paper displays. CalEPD extends the Adafruit_GFX class and is broken out in a separate repo, making it easy to consume on other projects. Since this supports dozens of different e-paper displays, this simplifies the process of building a calendar with different screens. The firmware includes a Bluetooth setup flow from a smartphone or tablet. This means you can quickly configure how often it wakes up, what it queries, and other important features.

The hardware shown in the demo video has a 7.5″ Waveshare screen with 800 x 400 resolution nestled inside a 3D-printed shell. There is also a 5,000 mAh battery with an ESP32 TinyPICO powering the whole system. The TinyPICO was picked for its incredible deep sleep power consumption. All this fits into a frame just 11 mm thick, for which STL files are available. [Martin] continues to work on this calendar display and has recently added support for FocalTech touch panel controllers. We’re excited to see where he takes it next!

This isn’t the first e-ink display project we’ve seen but this is a great reference to build your own. If you need another good starting point, this weather display might give you that little bit of inspiration you need.

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Cryptic Calendar Makes For A Useful Wall Ornament

Hackers love a good clock build, but its longer term cousin, the calendar, is more seldom seen in the wild. Regardless, they can be just as useful and elegant a project, as this cryptic design from [Wolfspaw] demonstrates.

The project consists of a series of rotating wheels, displaying a series of arcane symbols. When the markings on the wheel align correctly with the viewing window, they display the date, month, and day of the week, respectively. The wheels themselves are fitted with 3D printed gear rings, which are turned by stepper motors under the control of an Arduino Nano. Hall effect sensors and magnets are used to keep everything appropriately aligned, while a DS3231 real time clock handles timekeeping duties.

It’s a tidy build, and we think the cryptic design adds a little mystery, making this an excellent conversation piece. The build is actually a remix of a project we’ve featured before, scaled and given a unique twist to suit [Wolfspaw]’s own personal aesthetic. Video after the break.

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Concentric Rings Keep This Calendar Perpetually Up To Date

The variety of ways that people find to show the passage of time never ceases to amaze us. Just when you think you’ve seen them all, someone comes up with something new and unusual, like the concentric rings of this automated perpetual calendar.

What we really like about the design that [tomatoskins] came up with is both its simplicity and its mystery. By hiding the mechanism, which is just a 3D-printed internal ring gear attached to the back of each ring, it invites people in to check it out closely and discover more. Doing so reveals that each ring is hanging from a pinion gear on a small stepper motor, which rotates it to the right point once a day or once a month. Most of the clock is made from wood, with the rings themselves made using the same technique that woodturners use to create blanks for turning bowls — or a Death Star. We love the look the method yields, although it could be even cooler with contrasting colors and grains for each segment. And there’s nothing stopping someone from reproducing this with laser-cut parts, or adding rings to display the time too.

Another nice tip in this write up is the trick [tomatoskins] used to label the rings, by transferring laser-printed characters from paper to wood using nothing but water-based polyurethane wood finish. That’s one to file away for another day.

A Desk Calendar With A Difference

With the office computer revolution now many decades old, many of the items that once stood on a typical desk are now part of history. The typewriter, the Rolodex, and the desk calendar have all been subsumed by computers and mobile phones. This electronic desk calendar is perhaps an exception, created as a promotional device for the RT-Thread IoT OS. It features an interesting take on a perpetual calendar, with an array of days spanned by a sliding frame such that any month’s days of the week can be depicted. The days are touch buttons, and can be used to bring up the information on an e-ink display.

Behind it all is a WinnerMicro W600 WiFi-enabled system-on-chip, that runs the aforementioned RT-Thread IoT OS. This OS is a bit of a mystery, according to its Wikipedia page it’s an open-source project from China with ten years of development behind it, but this appears to be the first time we’ve seen it here at Hackaday. Anyone using it?

We like this project though, for its perpetual calendar, and for its re-imagining of a bygone desk accoutrement with an e-ink display to conserve battery. It’s not the first e-ink calendar we’ve seen, this previous one used a Raspberry Pi.

Samsung’s Leap Month Bug Teaches Not To Skimp On Testing

Date and time handling is hard, that’s an ugly truth about software development we’ll all learn the hard way one day. Sure, it might seem like some trivial everyday thing that you can easily implement yourself without relying on a third-party library. I mean, it’s basically just adding seconds on top of one another, roll them over to minutes, and from there keep rolling to hours, days, months, up until you hit the years. Throw in the occasional extra day every fourth February, and you’re good to go, right?

Well, obviously not. Assuming you thought about leap years in the first place — which sadly isn’t a given — there are a few exceptions that for instance cause the years 1900 and 2100 to be regular years, while the year 2000 was still a leap year. And then there’s leap seconds, which occur irregularly. But there are still more gotchas lying in wait. Case in point: back in May, a faulty lunar leap month handling in the Chinese calendar turned Samsung phones all over China into bricks. And while you may not plan to ever add support for non-Gregorian calendars to your own project, it’s just one more example of unanticipated peculiarities gone wild. Except, Samsung did everything right here.

So what happened?

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Introducing The Hackaday Calendar Of Virtual Events

For many of us, the social distancing procedures being used to help control the spread of COVID-19 have been a challenge. We can’t go to our hackerspaces, major events have been postponed or canceled entirely, and even getting parts has become difficult due to the immense pressure currently being placed on retailers and delivery services. For even the most stoic hacker, these are difficult times.

But you don’t have to go through it alone. We might not be able to meet in person, but that doesn’t mean the exchange of thoughts and ideas has to stop. Hackaday has started up a calendar of events you can use to keep track of virtual classes and hangouts that you can take part in from the comfort of your own home. You don’t even need to wear pants (but you should, just to be safe).

Hacker Check-in returns tomorrow at 5pm Eastern time and this weekend is packed with must-see entries. You can start your Saturday by taking part in a KiCad/FreeCAD meetup, sit in on the BSides Atlanta security conference, jump over to a hardware show and tell in New Delhi, and then cap things off with an introduction to quantum computing presented by Kitty Yeung.

Looking to be more than an idle participant? If you want to teach a class, host a show and tell, or put together a round-table discussion, drop a line to superconference@hackaday.io. Pretty much anything of interest to the hacking and making community is fair game, and who knows when you’ll ever get another chance at a captive audience like this. When you haven’t left the house in a week, there’s not a whole lot you won’t watch online.

It’s easy to see social distancing as an overreaction, but the numbers don’t lie. Things are serious out there, especially in the dense population centers where hacker events generally take place. By staying home and taking part in events virtually, we can do our part to control the spread of this virus and hopefully return things to normal that much sooner.