The In-Circuit SD Card Switch

SDISP

For nearly every problem, it’s possible to engineer a solution, even if you’re dealing with an extraordinarily niche problem that might only apply to yourself. [Joel] wanted to be able to program the microSD card in his BeagleBone with a new bootloader or file system without removing the SD card from the target board. This is a peculiar requirement, and it’s highly doubtful a product or even a circuit exists for such a function. This meant [Joel] would need to roll his own board to accomplish the task.

The board is remarkably simple, housing a single microSD socket, two expansion headers for a microSD sniffer for a computer and an embedded board, an FTDI header, and a pair of 4-bit multiplexer/demultiplexers. The operation of the device is fairly straightforward: send a signal down the FTDI cable, and the board switches the onboard SD card from one device to another.

[Joel] has a video of his screen that shows him pulling off in-circuit SD card reading and writing. You can check that out below.

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A cortex M4 based platform with ETH, USB, BT and many on-board peripherals

Here is a very time consuming project that I worked on during last summer: an ARM Cortex M4 based platform with plenty of communication interfaces and on-board peripherals. The particular project for which this board has been developed is not really HaD material (one of my father’s funny ideas) so I’ll only describe the platform itself. The microcontroller used in the project is the ATSAM4E16C from Atmel, which has 1Mbyte of flash and 128Kbytes of SRAM. It integrates an Ethernet MAC, a USB 2.0 Full-speed controller, a sophisticated Analog to Digital Converter and a Digital to Analog Converter (among others).

Here is a list of the different components present on the board so you can get a better idea of what the platform can do: a microphone with its amplifier, a capacitive touch sensor, two unipolar stepper motors controllers, two mosfets, a microSD card connector, a Bluetooth to serial bridge, a linear motor controller and finally a battery retainer for backup power. You can have a look at a simple demonstration video I made, embedded after the break. The firmware was made in C and uses the Atmel Software Framework. The project is obviously open hardware (Kicad) and open software.

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Dell Streak screen repair yields a few welcome surprises

dell-streak

[Rupert’s] friend cracked the screen on his beloved Dell Streak 5 phone and handed it off to see if [Rupert] could repair it. He says that the glass replacement was a relatively straightforward affair – a process he documented in thorough detail worthy of iFixit.

He did come across a few interesting tidbits along the way, including an Atmel Mega168P hanging out on the broken screen’s digitizer board, which now resides in his parts bin. The most intriguing thing [Rupert] discovered however was that the phone’s on-board memory chip wasn’t soldered in as he would have expected. Instead, he found a standard microSD slot with a 2GB card in tow. He didn’t happen to have a larger card on hand, but after researching a bit he did find out that swapping the card is a relatively simple process.

If you happen to have one of these phones sitting around, or come across a damaged unit at any point, it definitely seems worth it to resurrect it and change the factory card out for something along the lines of a 32GB model. We certainly wouldn’t complain if we had a rooted 32GB Streak kicking around!

Tiny MP3 module is perfect for your next project

tiny_embedded_mp3_module

If your next project needs the ability to play MP3s but you don’t have a lot of room to spare in your enclosure, [Boris] has just the thing you need. His tiny embedded MP3 module supports playback of up to 65,536 songs or as many as you can fit on a 16GB microSD card, which isn’t bad in the least.

The module relies on a PIC24F for input and control, while a VS1011 handles all of the MP3 decoding responsibilities. He says that the module would be great for voice-enabled vending machines, telephone systems, cars, and more.

With such a wide range of possible applications, he decided that the module should be able to support several different input methods. The board can be controlled via a set of digital input buttons, which is perfect for direct human interaction, while it also supports serial control for scenarios where it is part of a larger embedded system.

Of course, we’ve seen tiny MP3 players like this before, but we like the fact that this module was designed to operate in standalone mode or as a component in a larger device. Of course all of the device’s schematics, code, and a BoM are available, allowing you to build your own if you are comfortable with SMD soldering.

Tiny Atari 810 Disk Drive upgrade

Everything gets smaller as technology improves. [Rossum] reduced the space needed for an Atari 810 disk drive by building this tiny replacement. Of course it doesn’t use floppy disks, but takes a microSD card instead. And it doesn’t stand in the place of one floppy drive, but can emulate up to eight different drives. The best part is that [Rossum] went to the trouble of designing an enclosure and having it fabricated via 3D printing in order to look just like a doll house version of the original hardware. It uses an LPC1114 ARM Cortex-M0 microprocessor to translate data transmissions to and from the Atari hardware, storing it on the 8 GB card.

As usual, you’ll soon find the schematic, board artwork, and code up on his git repository soon.

Single-chip digital audio player

[Dmitry Gr.] built a simple circuit to playback digital audio. At the center you can see an 8-pin PIC 12F1840 microcontroller. It’s pulling audio data from a microSD card which is read through a full-sized SD card adapter to which he soldered jumper wires for all of the necessary connections. There is one additional semiconductor, a FET which is used to drive the speaker seen to the left. Unregulated power is provided by a pair of AA batteries (four are seen in the picture above but only two are actually connected to the circuit). He’s planning to post his code package soon, but for now you’ll have to be satisfied with a couple of demo videos and a schematic. Both videos are embedded after the break, and we’ve also included a screenshot of the schematic which is shown in the second video.

This is very similar to the 1-Bit Symphony CD we saw almost a year ago in a links post. That one used a jewel case instead of the protoboard seen here, and had a headphone jack instead of the speaker.

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Propeller Platform prototyping board gets an upgrade

[Nick] over at Gadget Gangster has a new version of his prototyping hardware for Propeller microcontrollers, called the Propeller Platform USB. A little more than a year ago we looked at the last version which was larger, used a DIP processor, and came unassembled. The new version does come assembled because of the migration to surface mount components (which may take some of the fun out of it if you just love soldering kits). This not only reduces the board footprint, but makes room for more goodies. As the name implies, there’s now a mini-USB socket with a USB to UART bridge, a microSD card slot as been added, and the onboard EEPROM has been doubled. This is a nice hardware upgrade but the price has been upgraded by $25 as well. No worries, it’s open source so you can roll your own if you have the parts on hand.

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