No SD Card Slot? No Problem!

We feature hacks on this site of all levels of complexity. The simplest ones are usually the most elegant of “Why didn’t I think of that!” builds, but just occasionally we find something that is as much a bodge as a hack, a piece of work the sheer audacity of which elicits a reaction that has more of the “How did they get away with that! ” about it.

Such a moment comes today from [Robinlol], who has made an SD card socket. Why would you make an SD card socket when you could buy one is unclear, beyond that he didn’t want to buy one on an Arduino shield and considered manufacture his only option. Taking some pieces of wood, popsicle sticks, and paperclips, he proceeded to create a working SD card of such bodgeworthy briliance that even though it is frankly awful we still can’t help admiring it. It’s an SD card holder, and despite looking like a bunch of bent paperclips stuck in some wood, it works. What more could you want from an SD card holder?

Paperclips are versatile items. If an SD card holder isn’t good enough, how about using them in a CNC build?

Ask Hackaday: What’s in Your Digital Bugout Bag?

Your eyes pop open in the middle of the night, darting around the darkened bedroom as you wonder why you woke up. Had you heard something? Or was that a dream? The matter is settled with loud pounding on the front door. Heart racing as you see blue and red lights playing through the window, you open the door to see a grim-faced police officer standing there. “There’s been a hazardous materials accident on the highway,” he intones. “We need to completely evacuate this neighborhood. Gather what you need and be ready to leave in 15 minutes.”

Most people will live their entire lives without a scenario like this playing out, but such things happen all the time. Whether the disaster du jour is man-made or natural, the potential to need to leave in a big hurry is very real, and it pays to equip yourself to survive such an ordeal. The primary tool for this is the so-called “bugout bag,” a small backpack for each family member that contains the essentials — clothing, food, medications — to survive for 72 hours away from home.

A bugout bag can turn a forced evacuation from a personal emergency into a minor inconvenience, as those at greatest risk well know — looking at you, Tornado Alley. But in our connected world, perhaps it pays to consider updating the bugout bag to include the essentials of our online lives, those cyber-needs that we’d be hard-pressed to live without for very long. What would a digital bugout bag look like?

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Ask Hackaday: How On Earth Can A 2004 MP3 Player Read An SDXC Card?

What were you doing in 2004? Can you even remember 2004? Maybe it’s like the old joke about the 1960s, if you can remember it, you weren’t really there, man. Cast your mind back, [Lance Armstrong] was winning the Tour de France, and SpaceShipOne made it into space.

[Gregg Eshelman], wrote to us to say that in 2004 he bought an MP3 player. Ask your parents about them, they were what hipsters used before they had cassette tapes: portable music players that everyone thought were really cool back then, onto which music didn’t come from the Internet but had to be manually loaded from a computer.

Jokes about slightly outdated consumer electronics aside, [Gregg]’s player, a GPX MW3836, turned out to be a really good buy. Not only does it still work, it packs an unexpected bonus, it reads 64Gb SD cards when they are formatted as FAT32. This might not seem like a big deal at a cursory glance, but it’s worth considering a little SD card history.

Back when the GPX was made, the maximum capacity of an SD card was 2Gb, a figure that must have seemed huge when the standard was created, but by the middle of the last decade was starting to look a little cramped. The GPX player is designed to only read these original 2Gb cards. In the years since then there have been a couple of revisions to the standard, SDHC, and SDXC, which have given us the huge cards we are used to today. Many other devices from the 2Gb SD era, made before SDHC and SDXC existed, cannot read the modern cards, yet [Gregg]’s GPX can.

Hackaday’s readership constantly amaze us with the sheer breadth of their knowledge and expertise, so we are sure that among you reading this piece will be experts on SD card standards who can shed some light on this mystery. Why can a player designed for the original SD card standard read the much newer cards when other contemporary ones can not? [Gregg] would love to know, and now our curiosity has been whetted, so would we.

If you think you’ve heard [Gregg]’s name before, it might be for his expertise in resin casting automotive parts.

SD card image: Andreas Frank (CC BY 2.5).

Add a Second SD Card to the Pi Zero

The Raspberry Pi Zero is a beautiful piece of hardware, fitting an entire Linux computer into a package the size of a pack of gum (don’t chew it, though). However, this size comes with limited IO options, which can be a complication for some projects. In this case, [Hugatry] wanted extra storage, and devised a smart method to add a second SD card to the Pi Zero.

The problem with the Pi Zero is that with only a single USB port, it’s difficult to add any other storage to the device without making things bulkier with hubs or other work arounds. Additionally, the main SD card can’t be removed while the Pi is running, so it makes sense to add an easy-to-use removable storage option to the Pi Zero.

It’s quite a simple hack – all that’s required to pull it off is a few resistors, an SD card connector, and some jumper wires. With everything hooked up, a small configuration change enables the operating system to recognise the new card.

Overall it’s great to see hacks that add further functionality to an already great platform. If you find it’s not powerful enough, you can always try overclocking one. 

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Roll Your Own 64GB SD Card From An EMMC Chip

It’s well-known that buying Flash storage devices from cheap online retailers is fraught with danger. Stories abound of multi-gigabyte drives that turn out to be multi-megabyte ones engineered to falsely report their capacity. So when [Jason Gin] found a source of 64GB Toshiba eMMC chips for only $6 per device he bought a few, but was prepared for disappointment.

To test them, he decided to use an SD card interface. There are minor differences between eMMC and SD, but the interfaces are electrically the same and in most cases an SD controller will happily do business with an eMMC. It was not however an easy task to connect the two — these eMMCs were in BGA packages, hardly the easiest ones to work with. He resorted to dead-bug soldering the relevant interface wires to SD lines, and connecting up his computer.

His first attempt was something of a failure, wiring the chip to the PCB of a cheap USB-to-SD adaptor. This did not put him off though, he followed it up by cracking open a very old 2GB SD card that contained a PCB instead of being potted, and soldering his eMMC in place of its Flash and controller. This even fit in the original SD housing, and met with success when plugged into more reliable SD card readers. He was thus able to confirm the capacity of his chips.

His blog post is worth a read for more than just the very fine soldering involved. He takes us through some of the intricacies of SD interfacing, as well as talking at length about the decoupling and termination required to make a reliable connection. We particularly like his use of an area of unconnected BGA balls as prototyping space for decouplers.

If you marvel at the exceptional dexterity required for hand BGA work, we’ve a couple of other treats for you. There is this TI infra-red sensor BGA soldered to a piece of stripboard, and this wafer-level chip package soldered to an SOIC prototyping board.

New Hard Drives for Old Computers

After a certain age, computers start to show signs that they might need to be replaced or upgraded. After even more time, it starts getting hard to find parts to replace the failing components. And, as the sands slip through the hourglass, the standards used to design and build the computer start going obsolete. That’s the situation that [Drygol] found himself in when he was asked to build a SD-card hard drive for an Atari.

The 8-bit Atari in question was a fixture of home computing in the 80s. In fact, if you weren’t on the Commodore train, it’s likely that your computer of choice was an Atari. For the nostalgic among us, a new hard drive for these pieces of history is a great way to relive some of the past. Working off of information from the SIO2SD Wiki page, [Drygol] used the toner transfer method to build a PCB, 3D printed a case, and got to work on his decades-old computer.

Resurrecting old hardware is a great way to get into retrocomputing. Old protocols and standards are worth investigating because they’re from a time where programmers had to make every bit count, and there are some gems of genius hidden everywhere. Whether you’re reworking SIO from an old Atari, or building a disk emulator for an Apple ][, there are lots of options.

Reflow Solder Your Micro SD to Ensure it Doesnt Go Anywhere

SD cards are great inexpensive storage for your embedded project. Using SPI,  they only take a few wires to hook up, and every micro-controller has a FAT file system interface to drop in your project. Problem with SD cards are the connectors.

Usually connectors cost more than the brains of your project,  and the friction fit, spring loaded contacts are not ideal for temperature swings, humidity and high vibration applications. Wouldn’t it be nice if you could just solder the thing down, especially if you know you are never going to remove it?

[Timothée] decided to try and succeeded in reflow soldering a Micro SD card direct to a breakout board. While starting as a what if experiment, the PCB was laid out in Ki-Cad and sent off to a fab. Once returned the Micro SD was fluxed, tinned and fluxed again, then reflowed using an IR setup.

The end result is a handy breakout board where you never have to worry about someone swiping the card to jam in their camera, and is ready for any breadboard project.