Author: Jenny List

3197 Articles

The $4 Z80 Single-Board Computer, Evolved.

July 28, 2018 by 33 Comments

We feature hundreds of projects here at Hackaday, and once they have passed by our front page and disappeared into our archives we often have no opportunity to return to them and see how they developed. Sometimes of course they are one-off builds, other times they wither as their creator loses interest, but just occasionally they develop and evolve into something rather interesting.

One that is taking that final trajectory is [Just4Fun]’s Z80-MBC, a single board computer with only 4 ICs, using an Atmel microcontroller to simulate the Z80 support chips. It has appeared as a revised version, on a smart new PCB rather than its original breadboard, and with built-in SD card and RTC support through readily available breakout boards, and banked RAM for CP/M support. You may remember the original from last year, when it was also a Hackaday Prize entry and stage finalist. From a Hackaday perspective this is particularly interesting, because it shows how the Prize can help a project evolve.

The Atmega32A uses the Arduino bootloader with programming through the ICSP port, and full instructions are given in the hackaday.io project page alongside all the files required to build your own board. There is no mention of whether boards can be bought, but we’d say this could be a commercial-quality product if they chose to take it in that direction.

Why Have Only One Radio, When You Can Have Two?

July 28, 2018 by 4 Comments

There are a multitude of radio shields for the Arduino and similar platforms, but they so often only support one protocol, manufacturer, or frequency band. [Jan Gromeš] was vexed by this in a project he saw, so decided to create a shield capable of supporting multiple different types. And because more is so often better, he also gave it space for not one, but two different radio modules. He calls the resulting Swiss Army Knife of Arduino radio shields the Kite, and he’s shared everything needed for one on a hackaday.io page and a GitHub repository.

Supported so far are ESP8266 modules, HC-05 Bluetooth modules, RFM69 FSK/OOK modules, SX127x series LoRa modules including SX1272, SX1276 and SX1278, XBee modules (S2B), and he claims that more are in development. Since some of those operate in very similar frequency bands it would be interesting to note whether any adverse effects come from their use in close proximity. We suspect there won’t be because the protocols involved are designed to be resilient, but there is nothing like a real-world example to prove it.

This project is unique, so we’re struggling to find previous Hackaday features of analogous ones. We have however looked at an overview of choosing the right wireless tech.

Share Bike Surrenders Its Secrets To A Teardown

July 27, 2018 by 67 Comments

If you are fortunate enough to live in a tiny settlement of no significance then perhaps you will be a stranger to bike sharing services. In many cities, these businesses have peppered the streets with bicycles secured by electronic locks for which the “open sesame” command comes through a Bluetooth connection and an app, and it’s fair to say they have become something of a menace. Where this is being written there are several competing brands of dubious market viability, to take a trip across town is to dodge hundreds of them abandoned across pavements, and every one of our waterways seems to sport one as jetsam courtesy of our ever-creative late-night drunks.

However annoying they might be, these bikes are electronic devices, and it’s thus interesting to read a teardown of one courtesy of [Electric Dreams]. The bike in question is in Australia and comes from Ofo, and it is very much worth pointing out that it is their property and prying it open is almost certainly a crime.

The bike itself is a fairly unexciting and rugged, with the electronics sitting in a module incorporating a back wheel lock sitting somewhere above where the rear brake might be. Inside is a custom board with GPS, GSM, and Bluetooth, and unexpectedly for an Aussie bike, a Netherlands SIM. Underneath the board is a motor and gearbox to activate the lock, but none of these parts are unexpected. The interesting angle of us comes from the power source, which is a D-sized lithium thionyl chloride cell, a primary cell rather than the expected rechargeable. These cells have a huge energy capacity, but at the expense of a truly nasty electrolyte and a high internal resistance which means they are limited to delivering tiny currents lest they explode.  To power the radios and motor in the Ofo, the designer has added a supercapacitor which presumably charges slowly and can then dump the required power when needed.

So bike share bikes have no great surprises in their electronics but a minor one in their power source. Curiosity sated, no need for anyone else to break the law for another look. It’s interesting to see a large lithium thionyl chloride cell in the wild, and it would be even more interesting to know whether Ofo get good life from them. Maybe our commenters will know. Or perhaps someone should ask the Feds.

Thanks [xtra] for the tip.

A BCD Wristwatch You’d Want To Wear

July 24, 2018 by 4 Comments

Timepieces are a staple of Hackaday, we have featured so many of them over the years that for us to become really excited by a fresh one it must be particularly special. The days when simply breaking out the Nixies was enough are long past.

So this binary wristwatch project by [Sverd Industries] definitely caught our eye. Not for being particularly novel, after all binary LED clocks are not in themselves hard, but for the exceptionally high quality of its construction. It’s a simple enough design, with a real-time clock chip and an ATmega328 in its most power-sipping mode on a circular PCB with an array of LEDs as the display, and all contained within a 3D-printed shell.

This design has real quality, the discrete components are tucked underneath the board leaving the  ICs on the top with only the LEDs for company. The glass front is glued into place, and the shell is professionally 3D-printed. Power comes from a single CR2032, and to save battery life the LEDs are only activated by the press of a concealed button. We would wear this watch. For that matter, you would wear this watch. Take a look at the video below the break, and we’re sure you’ll agree. Looks like a few are even available over on Tindie.

This isn’t the first binary watch we’ve featured, so it’s tough to pick a comparison. This very low BoM example might lack some of the polish of the one presented here, but it has the same ability to catch our eye.

Continue reading “A BCD Wristwatch You’d Want To Wear” →

Sad Without A SID? This Comes Pretty Close

July 24, 2018 by 36 Comments

The MOS Technologies 6851, popularly known as the SID, is a legendary sound synthesiser integrated circuit from the early 1980s that is most famous for providing the Commodore 64 home computer with its ability to make noise. At the time it was significantly better than what could be found in competitor machines, making it a popular choice for today’s chiptune and demo scene artists.

There’s a snag for a modern-day SID-jockey though, the chip has been out of production for a quarter century and is thus in short supply. Emulation is a choice, but of little use for owners of original hardware so it’s fortunate that [Petros Kokotis] has produced a SID replacement using a Teensy 3.6.

The operation is simple enough, the Teensy provides all the requisite SID data lines via some level shifters for the host microcomputer, and uses [Frank Boesing]’s ReSID library to do the heavy lifting part of being a SID. You can download the code from a GitHub repository, and he’s posted a video we’ve put below the break showing a prototype in action with a real Commodore 64. The audio quality isn’t brilliant due to a phone camera recording from a very tinny speaker, but notwithstanding that it has the air of the real thing.

This isn’t the first SID we’ve seen here. How about a MIDI synth using one?

Continue reading “Sad Without A SID? This Comes Pretty Close” →

Fail Of The Week: ESP Walkie, Not-So-Talkie

July 23, 2018 by 51 Comments

The ESP8266 has become such a staple of projects in our community since it burst onto the scene a few years ago. The combination of a super-fast processor and wireless networking all on the same chip and sold in retail quantities for relative pennies has been irresistible. So when [Petteri Aimonen] needed to make a wireless intercom system for cycling trips it seemed an obvious choice. Push its internal ADC to sample at a high enogh rate for audio, and stream the result over an ad-hoc wi-fi network.

The result was far from satisfactory, as while early results with a signal generator seemed good, in practice it was unusable. Significant amounts of noise were entering the pathway such that the resulting audio was unintelligible. It seems that running a wireless network causes abrupt and very short spikes of power supply current that play havoc with audio ADCs.

He’s submitted it to us as a Fail Of The Week and he’s right, it is a fail. But in a way that’s an unfair description, because we can see there is the germ of a seriously good idea in there. Perhaps with an external ADC, or maybe with some as-yet-to-be-determined filtering scheme, an ESP8266 walkie-talkie is one of those ideas that should be taken to its conclusion. We hope he perseveres.

IHC Badge: It’s Not (Quite) A Nokia

July 22, 2018 by 16 Comments

Electronic conference badges are an integral part of our culture, and have featured many times here. The norm for a badge is an exquisitely designed printed circuit board with some kind of microcontroller circuit on it, often a display, and some LEDs.

This is not enough though for [Mastro Gippo], for he has given us an interesting alternative, the shell of a Nokia 3310 mobile phone fitted with a new motherboard holding an ESP32 module, and of course that classic display. It is to be the badge for IHC Camp, which initialism if you hadn’t guessed stands for Italian Hacker Camp, and which will run from the 2nd to the 5th of August 2018 in Padova, Italy. It’s worth reminding readers, at the time of writing IHC tickets are still available, so get ’em while they’re hot!

The board itself is a beautiful piece of work, and aside from the Nokia’s keyboard and display it holds the ESP module and an STM32F103 microcontroller that handles all the peripherals. There is no microphone, after all this is a badge rather than a phone, but there is space for a LoRa module. He’s done another fascinating post about the PCB design, including the on-board wireless antenna.

We have seen a lot about badges from the #BadgeLife scene surrounding the USA’s DEFCON courtesy of our colleague [Brian Benchoff], so it is particularly interesting to see badges from the opposite side of the Atlantic. This is an artform whose journey still has a way to go, and we’ll be along for the ride!