Restoring the Full Capacity of an SD Card

During my projects with single board computers with embedded Linux like the Raspberry Pi, the Beaglebone Black, pcDuino or the Cubieboard, often happens when I need to use and reuse SD cards to install Operating Systems into the boards. However, if later you want to use that same card as a normal storage unit, you might be surprised when you find out that a few MB or even GB are missing and worst, a simple formatting just won't fix the problem.

This happens because the card was formatted to be used with a Linux partition and Windows simply doesn't know how to deal with that. Fortunately there's a tool for that.

3D Printed DNA Lamp

A few months ago I was browsing online through some 3D models for 3D printing and I noticed there was some DNA strands that caught my attention. They looked nice, however they were not really ready for 3D printing, at least for most printers. Still, I was moving them around on the browser and I realized they created an amazing upwards and downwards effect when rotating them. I thought, if it looked that nice on my computer screen, it must be even more hypnotizing if it actually existed. Then this thought came to my mind: what if I would print a DNA strand, and put it over a rotating platform and make it a lamp? And thus, the idea for this project was born.

It was a good time to have this idea because, coincidently there was 3D printing contest happening on Instructables with some really nice prizes, so I thought about entering the contest with this project. Since I published a fully detailed tutorial of the entire project on Instructables, I won't get into details here. The files are available for download at My Mini Factory. If you're not into DIY you can just get one on Tindie.

MSP430 BSL Rocket EMF Detector

A few months ago I received the MSP430-BSL Rocket from Texas Instruments Europe, as a prize for a Facebook contest. The Rocket is a low-cost programmer for MSP430 devices but since it has its own microcontroller, I thought it would be fun to use it for another application: an EMF detector! By the way if you need a TI launchpad, I'm selling a few of mine on Tindie.

Since it has a rocket shape, I had the idea to build a custom flame shaped PCB for the output LEDs, which I could plug through the 2x5 pins BSL connector.

Power over Ethernet Adapter

This was probably the simplest and yet one of the most successful projects I ever made. A Power over Ethernet or PoE Adapter, which allows the usage of Ethernet cable to transmit not only data but power as well for the network equipments.

There are 2 pairs of wires that are not used on UTP cables for communication on 10/100Mbps networks. So these adapters will allow you to use those wires for power transmission.

SRAM Memories

A Static Random Access Memory, best known as SRAM, is a type of memory that keeps the data stored as long as it's powered, therefore considered a volatile memory. Unlike the DRAM memories, the SRAM doesn't need to be periodically refreshed, which allows for higher access speeds, however they're usually more expensive, consume more power, take up more space and heat more than the DRAM alternative.

Here I'll explain how I designed a small 32 bit SRAM memory (8 rows of 4 bits) for academic purposes. The goal was to design the memory cells and the necessary circuits to its operation, and then to implement the respective layout. The complete circuit was needed to be able to simulate the read and write cycles, while analysing the results.