Custom Calculator Rolls D20 So You Don’t Have To

There are a number of sticking points that can keep new players away from complex tabletop games such as Dungeons & Dragons. Some people are intimidated by the math involved, and of course others just can’t find enough friends who are willing to sit down and play D&D with them in 2019. While this gadget created by [Caleb Everett] won’t help you get more open minded friends, it will take some of the mental gymnastics out of adding up dice rolls.

In its current form the device saves you from the hassle of not only having to roll various combinations of physical dice, but adding up all the faces after the fact as well. In the future [Caleb] plans on adding more advanced software features which will allow for tricks not possible with real dice, such as increasing the likelihood of rolling numbers which haven’t been seen in awhile. Now that the hardware is put together, he’s free to dig into the software side of things and really get creative.

Inside the 3D printed case of his calculator there’s a Adafruit Feather M0 Express, a 128 x 32 OLED display, and a 2200 mAh lithium ion battery that lets him go mobile. The keys, which are Cherry MX clones, are wired directly to the digital pins of the Feather board as [Caleb] found that easier to wrap his head around than doing a matrix. This ended up working out as he had enough pins, but does stifle future expansion a bit.

Even if you aren’t into the sort of tabletop gaming which would benefit from an automatic dice roller and tabulator, we think [Caleb] has come up with a very neat form factor for similar pocket sized gadgets. It reminds us of the Handlink from Quantum Leap; before the prop department swapped it out for a jumble of gummy bears later on in the series, anyway. Since he’s shared the link to the OnShape project, you can even tweak the design a bit without having to suffer through modifying the STLs.

Many of the electronic dice we’ve seen in the past have tried to emulate the size and appearance of traditional dice, so it’s interesting to see this approach which goes in the opposite direction entirely. Critics might say that at some point you’d be better off just using a software application for your smartphone, but we’re not in the business of complaining when people produce interesting pieces of hardware.

Finally, An Open Source Calculator

Microsoft has released the code for the Calculator app. This move is the latest in Microsoft’s efforts to capitalize on the Open Source community. Previous efforts have been the Open Sourcing of an extremely old version of DOS, and shoehorning Linux into Windows somehow in a way that’s marginally more user-friendly than spinning up a VM or popping over to your Linux partition. Oh yeah, Microsoft bought Github. Can’t forget that.

The release of the code for the Calculator app means now you too can truly verify all your calculations are correct. To build the Calculator app, you’ll need a Windows 10 computer and Visual Studio. You might think that this is the same code that’s been shipping for 30 years — it’s a simple calculator, right? Not so: the Calculator for Windows 8 had a strange and odd bug where the square root of 4, minus two, did not equal zero. Floating point is hard, kids.

Of special interest to the community, it’s now possible to disable telemetry sent from the Calculator app to Microsoft servers. Yes, the Calculator app knows you forgot how to divide, and wow man, six times nine, you needed help with that?  Fortunately, telemetry can be disabled in developer’s builds by disabling the SEND_TELEMETRY build flag. Now Microsoft won’t know you don’t do math so good.

At the time of this writing, we could not be bothered to contact Microsoft to find out when the pinball game or Ski Free will be updated and Open Sourced.

Pocket Forth Invades Your TI Calculator

TI certainly have certainly seen off rivals such as HP or Casio to capture the lion’s share of the calculator market. The TI-84 is a real staple, and with as many units as there are out there, hacking them is a given. However, selecting an operating system for the machine can be a hassle. TI-OS is proprietary and doesn’t really want to let you do everything you’d like to. There are alternatives, but many of them won’t let you easily use your calculator to be — well — a calculator.

[Siraben] has zkeme80 which is essentially ANS Forth (mostly) with extensions for the TI hardware. You can easily extend the system, of course, because it is Forth. You can also use the machine for its intended purpose easily.

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1973: When Calculators Were Built Like Computers

Should you ever pick up [Steve Wozniak]’s autobiography, you will learn that in the early 1970s when his friend [Steve Jobs] was working for Atari, [Woz] was designing calculators for Hewlett Packard. It seems scarcely believable today, but he describes his excitement at the prospects for the calculator business, admitting that he almost missed out on the emerging microcomputer scene that would make him famous. Calculators in the very early 1970s were genuinely exciting, and were expensive and desirable consumer items.

[Amen] has a calculator from that period, a Prinztronic Micro, and he’s subjected it to an interesting teardown. Inside he finds an unusual modular design, with keyboard, processor, and display all having their own PCBs. Construction is typical of the period, with all through hole components, and PCBs that look hand laid rather than made using a CAD package. The chipset is a Toshiba one, with three devices covering logic, display driver and clock.

The Prinztronic is an interesting device in itself, being a rebadged 1972 Sharp model under a house brand name for the British retailer Dixons, and that Toshiba chipset is special because it is the first CMOS design to market. It was one of many very similar basic calculators on the market at the time, but at the equivalent of over 100 dollars in today’s money it would still have been a significant purchase.

Long-tern Hackaday readers will remember we’ve shown you at least one classic calculator rebuild in the past, the venerable 1975 Sinclair!

Button, Button, Who’s Got the (One) Button?

We often think that less is more, but what can you do with a device that has only a single button? [Volos] wondered the same thing and he built an Arduino with a single button and a display. After doing some obvious things  (like a counter or stopwatch) he decided to make a calculator.

You can find the source code online and he used a library from GitHub to handle the reaction to single presses, double presses, and long presses. Is it ideal? Probably not. But if you only have a limited amount of space or pins, it can make the difference between a feasible project and one you can’t finish.

His original projects also included a Flappy Bird clone. The OLED display is only 64×48 so that’s not a lot of room. The packaging of the tiny Arduino, the battery, and the display in a good looking case, was pretty impressive. So the device might be usable for something.

Of course, the library will work with any program and there’s no reason you can’t have more than one button and simply multiply their functions with the same strategy. There’s a sample on GitHub that shows how you can create two OneButton objects connected to different hardware devices.

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Count To F Easily With This DIY Calculator

Some of the greatest electronic calculators of all time, including the venerable HP-16C, included functionality to convert numbers between different bases. 3735928559 might not mean much in base 10, but convert that to hex, and you’ll offend vegetarians. If the great calculators of yore had a way to convert between number bases, that means someone must make a standalone device to do the same, right? That’s what [leumasyerrp] is doing for their entry into the Hackaday Prize, anyway.

The Base Convert project is a simple desktop calculator designed to convert between hexadecimal, decimal, and binary. To do this, there’s an 8×8 key matrix for the numbers 0 through F. There are sixteen single LEDs, four seven-segment LEDs for the hex display, and six seven-segment LEDs for the decimal display.

While this is really just a project [leumasyerrp] came up with to learn the MSP430 microcontroller, this looks like a fantastic project given it’s great use of milled PCB for a front panel, careful selection of standoff height, and everything is tucked away into a package that looks about as professional as you can expect from a device made entirely from PCBs. Of course, the Base Convert calculator works as expected, and can easily change between number bases.

Sometimes it’s not about building the hardest or most complex project, but instead simply putting the most amount of polish into a simple project. This is a project that does that well, and we’re happy to have this in the running for the Hackaday Prize.

DIY Scientific Calculator Powered By Pi Zero

It’s the eternal question hackers face: do you built it, or do you buy it? The low cost and high availability of electronic gadgets means we increasingly take the latter option. Especially since it often ends up that building your own version will cost more than just buying a commercial product; and that’s before you factor in the time you’ll spend working on it.

But such concerns clearly don’t phase [Andrea Cavalli]. Sure he could just buy a scientific calculator, but it wouldn’t really be his scientific calculator. Instead, he’s taking the scenic route and building his own scientific calculator from scratch. The case is 3D printed, the PCB is custom, and even the software is his own creation.

His PCB hooks right up to the GPIO pins of the internal Raspberry Pi Zero, making interfacing with the dome switch keyboard very easy. The board also holds the power management hardware for the device, including the physical power switch, USB connection for charging, and TPS79942DDCR linear regulator.

The case, including the buttons, is entirely 3D printed. At this point the buttons don’t actually have any labels on them, which presumably makes the calculator more than a little challenging to use, but no doubt [Andrea] is working on that for a later revision of the hardware. A particularly nice detail is the hatch to access the Pi’s micro SD card, making it easy to update the software or completely switch operating systems without having to take the calculator apart.

After the kernel messages scroll by, the Pi boots right into the Java calculator environment. This gives the user a fairly standard scientific calculator experience, complete with nice touches like variable highlighting. The Mario mini-game probably isn’t strictly required, but if you’re writing the code for your own calculator you can do whatever you want.

Here at Hackaday we’ve seen a calculator that got a Raspberry Pi upgrade, a classic scientific calculator emulated with an Arduino, and of course we’ve raved about the NumWorks open source graphing calculator. Even with such stiff competition, we think this project is well on its way to being one of the most impressive calculators we’ve ever come across.

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