The AAduino Is An Arduino In An AA Battery

You might think that there could be no form factor that has not as yet had an Arduino fitted in to it. This morning a new one came our way. [Johan Kanflo]’s AAduino is an Arduino clone with an onboard RF module that fits within the form factor of an AA battery. Putting the Arduino inside its own battery pack makes a very neat and compact self-contained unit.

At the heart of the board is an ATmega328 clocked at 8MHz to reduce power consumption and fused to drop out at 1.7V. The radio module is a HopeRF RFM69C which as supplied is a little bit too big for the AA form factor so [Johan] has carefully filed away the edge of the PCB to make it fit. Enough room is left within the shape of an AA cell for a couple of DS18B20 temperature sensors and an indicator LED. He provides a handy buyer’s guide to the different versions of a 3xAA box with a lid, and all the files associated with the project are available in his GitHub repository.

Especially with the onboard radio module we can see that the AADuino board could be a very useful piece of kit. Perhaps for instance it could be used as a very low power self-contained UKHASnet node.

We’ve featured quite a few Arduino clones over the years that try to break the size mould in some way. This stripboard Arduino almost but not quite equals the AAduino’s size, as does this PCB version barely wider than the DIP package of its processor. But the AADuino is a bit different, in that it’s a ready-made form factor for putting out in the field rather than just another breadboard device. And we like that.

At last! A SIL-Duino!

There are some standard components that have been so continuously refined as to have become if not perfect then about as good as they’re going to get. Take the Arduino Uno for instance, and compare it with its ancestor from a decade ago. They are ostensibly the same board and they are compatible with each other, yet the Uno and its modern clones have more processing power, memory and storage, a USB interface rather than serial, and a host of small component changes to make them better and cheaper.

You’d think that just another Arduino clone couldn’t bring much to the table then. And you’d be right in a broad sense, just what is there left to improve?

[Clovis Fritzen] has an idea for an Arduino clone that’s worth a second look. It’s not an amazing hardware mod that’ll set the Arduino world on fire, instead it’s a very simple design feature. He’s created an Arduino that mounts vertically on a single row of pins. Why might you find that attractive, you ask? A SIL vertical Arduino takes up a lot less breadboard space than one of the existing DIL Arduinos. A simple idea, yet one that is very useful if you find yourself running out of breadboard.

[Clovis] took the circuit of an Arduino Uno and simplified it by removing the USB interface, so this board has to be programmed through its ICSP header. And he’s made it a through-hole board for easy construction by those wary of SMD soldering. The resulting board files can all be found on GitHub.

Every now and then along comes a hack so simple, obvious, and useful that it makes you wonder just why you didn’t think of it yourself. Many of us will have used a DIL Arduino and probably found ourselves running out of breadboard space. This board probably won’t change the world, but it could at least make life easier in a small way for some of us who tinker with microcontrollers.

This is just the latest of many Arduino clones to find its way onto these pages. In 2013 we asked why the world needed more when featuring one made as a PCB design exercise. There’s even a Hackaday version called the HaDuino developed by [Brian Benchoff]. But while it’s true that Yet Another Vanilla Arduino Clone brings nothing to the table, that should not preclude people from taking the Arduino and hacking it. Every once in a while something useful like this project will come from it, and that can only be a benefit to our community.

It’s a Sega It’s a Nintendo! It’s… Unique!

Before the days of the RetroPie project, video game clones were all the rage. Early video game systems were relatively easy to duplicate and, as a result, many third-party consoles that could play official games were fairly common. [19RSN007] was recently handed one of these clones, and he took some pretty great strides to get this device working again.

The device in question looks like a Sega Genesis, at least until you look closely. The cartridge slot isn’t quite right and the buttons are also a little bit amiss. It turns out this is a Famicom (NES) clone that just looks like a Sega… and it’s in a terrible state. After a little bit of cleaning, the device still wasn’t producing any good video, and a closer inspection revealed that the NOAC (NES-on-a-Chip) wasn’t working.

Luckily, [19RSN007] had a spare chip and was able to swap it out. The fun didn’t stop there though, as he had to go about reverse-engineering this chip pin-by-pin until he got everything sorted out. His work has paid off though, and now he has a video game system that will thoroughly confuse anyone who happens to glance at it. He’s done a few other clone repairs as well which are worth checking out, and if you need to make your own NES cartridges as well, we’ve got you covered there, too.

Colorizer for ZX81 clone

[danjovic] is a vintage computer enthusiast and has several old computers in his collection. Among them are a couple of TK-85 units – a ZX81 clone manufactured by Microdigital Eletronica in Brazil. The TK-85 outputs a monochrome video output. And when [danjovic] acquired a SyncMaster 510 computer monitor, he went about building a circuit to “colorise” the output from the ZX81 clone (Portuguese translation).

The SyncMaster 510 supports 15kHz RGB video refresh rate, so he thought it ought to be easy to hook it up to the TK-85, which internally has the video and composite sync signals available. So, if he could lower the amplitude of the video signal to 0.7Vpp, using resistors, and connect this signal to one of the primary colors on the monitor, for example green, then the screen should have black characters with a green background.

DSCN5584-thumbBefore he could do any of this, he first had to debug and fix the TK-85 which seemed to be having several age related issues. After swapping out several deteriorating IC sockets, he was able to get it running. He soldered wires directly to one of the logic chips that had the video and sync signals present on them, along with the +5V and GND connections and hooked them up to a breadboard. He then tested his circuit consisting of the TTL multiplexer, DIP switches and resistors. This worked, but not as expected, and after some digging around, he deduced that it was due to the lack of the back porch in the video signal. From Wikipedia, “The back porch is the portion of each scan line between the end (rising edge) of the horizontal sync pulse and the start of active video. It is used to restore the black level (300 mV.) reference in analog video. In signal processing terms, it compensates for the fall time and settling time following the sync pulse.”

To implement the back porch, he referred to an older hack he had come across that involved solving a similar problem in the ZX81. Eventually, it was easily implemented by an RC filter and a diode. With this done, he was now able to select any RGB value for foreground and background colors. Finally, he built a little PCB to house the multiplexer, DIP switches and level shifting resistors. For those interested, he’s also documented his restoration of the TK-85 over a four-part blog post.

The RUM 80 – a home brew Z80 computer built from scratch

[M] recently tipped us off about hacker [Lumir Vanek] from the Czech Republic. Between 1985 and 1989, [Lumir] built his own home brew, Z80 based computer. The list of home computers available in the 1980’s is extensive. Those living in western Europe and the Americas could choose offerings from Acorn, Apple, Commodore, Atari, Radio Shack, and Sinclair Research to name just a few. Even the erstwhile Czechoslovakia had home computers available from Didaktik and Tesla.

[Lumir]’s built was based around the Z80 processor and is built using regular, double-sided, prototyping board. It featured the 8-bit Z80 processor CPU, 8kB EPROM with monitor and BASIC, two Z80 CTC timers, an 8255 parallel interface for keyboard and external connector, 64kB DRAM, and Video output in black & white, 40×25 characters, connected to a TV. The enclosure is completely made from copper clad laminate. [Lumir] documented the schematics, but there is no board layout – since the whole thing was discrete wired. He even built the membrane keyboard – describing it as “layers of cuprextit, gum, paper with painted keys and transparent film”. When he ran out of space on the main board, he built an expansion board. This had an 8251 serial interface for cassette deck, one 8-bit D/A converter, and an 8255 parallel port connected to the “one pin” BT100 printer.

On the software side, he wrote his own monitor program, which allowed simple interactions, such as displaying and modifying registers, memory, I/O ports and to run programs. He wrote this from scratch referring to the Z80 instruction set for help. Later he added a CP/M emulator. Since the Z80 had dual registers, one was used for user interaction, while the other was reserved to allow background printing. Eventually, he even managed to port BASIC to his system.

Check out [Martin Malý]’s awesome article Home Computers behind the Iron Curtain and the follow up article on Peripherals behind the  Iron Curtain, where you can read more about the “one pin” BT100 printer.

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A Smaller, Homebrew Amstrad

Although they weren’t very popular in America, the Amstrad CPC 464 and CPC 6128 were extremely well-received in Europe. [Zaxon] loved his ‘464, and for a bit of a learning experience – and the fact that an Amstrad takes up an exceptional amount of desk space – decided to make a clone of his favorite computer (.pl, Google translatrix).

The clone began as a simple schematic of the original Amstrad CPC 464, but the parts used in the original required some modern equivalents. Still, most of the old chips remained in the clone; the original Hitachi HD46505 CRT controller remains, as do the original DRAM chips and the vintage Z80 CPU.

A few modern amenities were added, including an interface for a PS/2 keyboard and a disk that’s much improved over the original cassette drive or weird 3.5″ disks: a Disk On Module, or basically a CompactFlash card in a strange form factor that plugs straight into a motherboard’s IDE socket. They’re mostly seen when tearing apart old thin clients, but using them in retrocomputing project is a great idea.

Thanks [rasz_pl] for the tip. Video below.

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A Real Raspberry Pi Clone (Not ‘Inspired By’)

odroid A few years ago, Broadcom had a pretty nice chip – the BCM2835 – that could do 1080 video, had fairly powerful graphics performance, run a *nix at a good click, and was fairly cheap. A Broadcom employee thought, “why don’t we build an educational computer with this” and the Raspberry Pi was born. Since then, Broadcom has kept that chip to themselves, funneling all of them into what has become a very vibrant platform for education, tinkering, and any other project that could use a small Linux board. Recently, Broadcom has started to sell the BCM2835 to anyone who has the cash and from the looks of it, real Raspberry Pi clones are starting to make their way into the marketplace.

Other Raspberry Pi clone boards out there like the Banana Pi and the HummingBoard don’t use the same BCM2835 found in the Raspi and the new Odroid. The new board also has the same 26 pin GPIO expansion socket, and runs the same binaries as the Raspberry P;. It is a clone in every sense, with a slightly different form factor geared towards very tiny, portable, and battery-powered use cases.

Unlike the official Raspberry Pi Compute Module, the Odroid isn’t meant to be used as a system on module, shoved into any product that needs a fast-ish ARM core without needing engineers to actually design a circuit with an ARM. The Odroid is a cut-down, extremely minimalist version of the Raspi, perfect for any project where space is at a premium.

There are a few interesting features included on the Odroid: there’s an on-board battery connector, a real-time clock on the board, and more of the BCM2835 GPIOs are exposed (although not the same ones as the upgraded RPi Model B+). There’s no Ethernet, but odds are if you’re building something that’s battery-powered, you won’t need that anyway.

As far as price goes, you can pick one of these Odroids up for $30 USD, with $9 shipping from South Korea. That’s pretty comparable to the price of a real Raspberry Pi, but if the features in the Odroid are worth it to you, it might be a worthwhile clone.