Where We’re Calculating, We Don’t Need No Seven Segments!

October 18, 2020 by Jenny List 22 Comments

There have been many attempts at electronic numerical display technology over the decades since the first incandescent bulb or neon tube flickered into life at the command of a primordial computer, but the lowest common denominator has remained the humble seven segments. Here it might end, but for [Ken Yap] who has taken inspiration from a 1960s Sharp calculator to re-create a numerical display with only six segments.

This seemingly impossible feat is achieved by having six curved segments arranged as a figure-eight, which can render all the digits after a fashion, but which soon reveals why the extra segment made an appearance. The numbers that are made up of curves look good enough, but the straight lines in the 1, 4, and 7, are compromised by the diagonal, and the zero is curiously small at half the height. You can read the digits, but it takes getting used to.

What made sense to reduce the complexity of 1960s electronics is only a fascinating curiosity in 2020, but we maybe won’t see these displays appearing too often. You can take a look at it in the video below the break, and if you’re curious about the Sharp calculator which inspired it then you can take a look at its page in the Vintage Calculator Museum.

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Tiny Mario Clone On A Tiny Processor

October 14, 2020 by Jenny List 8 Comments

We’ve become used to seeing retro games running on commodity microcontrollers where once they would have required the bleeding-edge console hardware of their day. [Duncan]’s Mario clone takes the genre a little further, using not a processor with plenty of pins for peripherals, but instead the humble ATtiny85. Its eight pins drive two OLED displays, and accept input from the buttons of a cheap Nintendo-like controller.

The write-up is split between software and hardware sections, with all the software itself available from a GitHub repository. He’s bit-banging the i2C for the displays for an impressive turn of speed, and the ATtiny’s lack of pins is addressed by clever use of resistive dividers to present a different voltage for each button pressed. With a truth table of voltages he’s even able to detect multiple simultaneous button presses. Music is achieved with the chip’s limited resources by storing the sounds in EEPROM, and clocked it at 16 MHz for smooth gameplay.

The whole is mounted inside the shell of the controller, with its USB guts removed and replaced by a smart custom PCB. An unexpected problem with ground plane fill caused a temporary roadblock reading the buttons, but the finished product is a very Nintendo-like experience. We like it.

New BBC Micro:bit Adds Microphone And Speaker

October 13, 2020 by Jenny List 16 Comments

There’s an old tale that TV companies only need to make a few years of kids’ TV shows, because their audience constantly grows out of their offerings and is replaced by a new set with no prior knowledge of the old shows. Whether it’s true or not is up for debate, but does the same apply to single board computers aimed at kids? The original BBC micro:bit was first announced back in 2015 and must be interesting its second generation of kids by now, but that hasn’t stopped them bringing out a second version of the little educational computer. How do you update such a simple device? Time to take a look.

Edge connector shown on the original micro:bit design

The form factor of the new board is substantially the same as its predecessor, with the same edge connector and large connection pads, and the familiar LED matrix display. The most obvious additions are a small speaker and MEMS microphone allowing kids to interact with audio in their code, but less obvious is a new touch button in the micro:bit logo. The original had it in the silk screen layer, while the new one has it as copper for a capacitive sensor.

The silicon has an upgrade too, now sporting a Nordic Semiconductor nRF52833 running at 64 MHz and sporting 512k of ROM and 128k of RAM with built-in Bluetooth Low Energy. Binaries are incompatible with the original, however all the development environments can recompile code for a new universal binary format capable of running the appropriate software for either version.

The micro:bit has been more of a hit in schools than it has in our community, perhaps because it has the misfortune to have arrived alongside so many strong competitors. However it remains a powerful contender whose easy programming alongside the power of more traditional toolchains make it a good choice for kids and grown-ups alike. We took a look at the original back in 2016, if you are interested.

In Praise Of The DT830, The Phenomenal Instrument You Probably Don’t Recognise For What It Is

September 24, 2020 by Jenny List 132 Comments

If we had to make a guess at the single piece of electronic bench equipment owned by the highest proportion of Hackaday readers, it would not be a budget oscilloscope from Rigol, nor would it be a popular portable soldering iron like the TS100. Instead we’re guessing that it’s a multimeter, and not even the most accomplished one.

The DT830 is a genericised Chinese-manufactured 3.5 digit digital multimeter that can be had for an astonishingly low price. Less than a decent hamburger gets you an instantly recognisable plastic case with a chunky rotary range selector switch, and maybe a socket for some kind of transistor or component tester. Make sure that there is a 9 volt battery installed, plug in the pair of test leads, and you’re in business for almost any day-to-day electrical or electronic measurement. They’ve been available in one form or another for decades and have been the subject of innumerable give-aways and loss-leader offers, so it’s a reasonsble guess that you’ll have one somewhere. I have three as far as I know, they make great on-the-go instruments and have proved themselves surprisingly reliable for what they are. Continue reading “In Praise Of The DT830, The Phenomenal Instrument You Probably Don’t Recognise For What It Is” →

The ZX Microdrive: Budget Data Storage, 1980s Style

September 18, 2020 by Jenny List 53 Comments

An enduring memory for most who used the 8-bit home computers of the early 1980s is the use of cassette tapes for program storage. Only the extremely well-heeled could afford a disk drive, so if you didn’t fancy the idea of waiting an eternity for your code to load then you were out of luck. If you had a Sinclair Spectrum though, by 1983 you had another option in the form of the unique Sinclair ZX Microdrive.

This was a format developed in-house by Sinclair Research that was essentially a miniaturized version of the endless-loop tape carts which had appeared as 8-track Hi-Fi cartridges in the previous decade, and promised lightning fast load times of within a few seconds along with a relatively huge storage capacity of over 80 kB. Sinclair owners could take their place alongside the Big Boys of the home computer world, and they could do so without breaking the bank too much.

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A Tentacle That’s A Work Of Art

September 15, 2020 by Jenny List 8 Comments

We all bring our own areas of expertise to our work when we build the projects that find their way in front of Hackaday writers, for instance a software developer brings clever brains to their microcontroller, or an electronic engineer might bring a well-designed piece of circuitry. [Yvo de Haas] is a mechanical engineer, and it’s pretty clear from his animatronic tentacle that he has used his expertise in that field to great effect.

If you think it looks familiar then some readers may recall that we saw a prototype model back in February at Hacker Hotel 2020. In those last weeks before the pandemic hit us with lockdowns and cancellations he’d assembled a very worthy proof of concept, and from what we can see from his write-up and the video below he’s used all the COVID time to great effect in the finished product. Back in February the control came via a pair of joysticks, we’re particularly interested to see his current use of a mini tentacle as a controller.

At its heart is a linkage of 3D-printed anti-parallelograms linked by gears, with cables holding the tension and controlling the movement of the tentacle from a set of winches. The design process is detailed from the start and makes a fascinating read, and with its gripper on the end we can’t wait for an event that goes ahead without cancellation at which we can see the tentacle for real.

If you’d like to see more of [Yvo]’s work, maybe you remember his wearable and functioning Pip-Boy, and his working Portal turret.

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The Floppy Disk As A Portable Music Format

September 7, 2020 by Jenny List 27 Comments

We remember the floppy disk as the storage medium most of us used two decades or more ago, limited in capacity and susceptible to data loss. It found its way into a few unexpected uses such as Sony’s Mavica line of digital cameras, but outside those who maintain and use older equipment it’s now ancient history.

Seemingly not for [Terence Eden] though, who has made a portable audio player that uses a floppy disk as its storage medium. It came about with the realization that half an hour of extremely compressed audio could be squeezed onto a standard 3.5 inch floppy, and then that the Beatles’ A Hard Day’s Night album comes in at only a shade over that time. With some nifty manipulation of the compression command line and the judicious removal of some unnecessary metadata, the album can fit on a floppy in equivalent quality to the AM radio fans would have heard it over back in 1964.

The player would have been a major undertaking when the floppy was king, but in 2020 it’s simply a USB floppy drive, a Raspberry Pi, and a battery pack. He’s given us the full instructions, and no doubt a more permanent version could be built with a 3D-printed case.

We’re fascinated by the recent trend of storing audio on floppy disks, but despite the hipster vibe, we doubt the idea will catch on. It’s not the first floppy-based player we’ve seen, but the previous one was more of a fake player.