Concerned with your project’s power consumption but don’t want to constantly leave an ammeter wired in series with your power supply? [Rajendra] feels your pain and has recently documented his solution to the problem: a variable-output bench top power supply that clearly displays load current consumption among other things!

Everything is wired up in a nice roomy enclosure that has front-panel access to ±5V and variable outputs, an adjustment potentiometer, and even an input for an integrated frequency counter. A PIC16F689 MCU runs the show and displays the variable output voltage and current on a 16×2 character LCD. Although clearly useful as is, the PIC has plenty of I/Os and muscle left for future expansion and a capacitance meter has already been hinted at as and addition for version 2!

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[Ben Krasnow]  has recently completed a home-built scanning electron microscope and has posted a video of it in action on his blog.

The build itself was done quite creatively using many off-the shelf components. We particularly like how long threaded brass rods were used not only for the supports, but also to maintain column alignment and fine-tune the spacing between the various beam focusing components.  A large glass “bell jar” covers the entire apparatus and is sealed to the bottom plate when the air is removed from within by a mechanical vacuum pump.

In order to produce an image, an electron gun similar to one found in a conventional CRT television tube accelerates the electrons with a 5kV potential from the top of the microscope downwards through a long copper column. Along the way the beam is focused and manipulated by electronic lenses in much the same way that light would be handled by conventional optical lenses. Near the base of the main column there are electrostatic deflection plates placed orthogonally in the X and Y directions that allow for precise scanning of the beam across the sample’s surface. When this high-energy electron beam is scanned across the sample, scattering surface electrons are then picked up by a nearby detector consisting of a phosphor screen and photomultiplier – a system that supposedly allows for higher sensitivity than trying to measure the small numbers of electrons directly.

Although the resolution of the first few scans is only around 50uM, this early success clearly shows that the device functions as intended and will provide a great starting point for future refinement with the final goal being resolutions down to the 1uM range.

Despite Ben’s reassurance that the x-rays produced at this energy level  won’t even penetrate the glass chamber, you can be sure that if we ever visit his garage we will definitely be donning some tin foil protection like these guys.

[Thanks kyle]

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TI has recently been fighting to gain traction in the market of low-cost microcontroller development platforms with products such as the MSP430 Value Line Launchpad.  In order to meet the needs of a rapidly growing customer base and appeal to a broader market they have recently released Grace beta Graphical Peripheral Configuration Tool. Grace is a plugin for TI’s own Code-Composer Studio (CCS) IDE that allows users to graphically control many aspecst of MSP430 development and is compatible with all MSP430F2xx/G2xx MCUs.

Utilizing a simple “wizard-like” interface, Grace allows users to quickly and efficiently control peripherals such clocks, timers, OpAmps,  ADCs, GPIOs, comparators, and even more advanced features such as serial communications or the configuration of low-level register settings. Once everything is configured as desired, Grace outputs standard C code that can be debugged and handled as if it were hand-written.

Although Code-Composer Studio is not free, there is a 30-day full-featured trial available as well as other (restricted) free licensing options as well. Since CCS is based on the Eclipse open-source  software development framework, perhaps we will see other similar development tools in the near future. Although not an apples-to-apples comparison, we could imagine that such a tool might provide many novice users with a simple and cost-effective alternative to the Arduino IDE.

The questions then becomes: If a later incarnation were to raise the MSP430 line to “Arduino-killer” status, would it be rejoiced as such or would it simply then become a new target for those die-hard microcontroller purists who love to shout “overkill” on the forums at the slightest provocation? Of course we would love to hear your take in the comments below!

Instructables user [jorgegunn] has put a unique spin on a recent geocache build by incorporating speech recognition and requiring that the “finder” knows the secret password to access the loot contained within. Although we won’t spoil the fun here, the techie spirit of the build was further bolstered by choosing a password fitting for any trekkie.

Despite utilizing an off-the-shelf speech recognition circuit kit, the majority of this hack was accomplished using parts available at local electronics and hardware stores. [jorgegunn] went to great lengths to make this hack accessible to any amateur hobbyist  and even includes links to relevant tutorials, schematics, and online parts vendors where applicable.

The actual speech recognition is accomplished with an Images Scientific Instruments model SR-06 circuit kit, capable of recognizing up to 40 different predefined words across multiple languages. Any time a correct match occurs, a value corresponding to the memory slot for that word is displayed on a pair of 7-segment displays. A separate decoder circuit based on a 74LS373 D-Type Latch and 4028 IC Decoder CMOS determines if the value being displayed constitutes a valid response and then drives a solenoid via a Darlington transistor in order to release the latching mechanism. Once opened, the device is simply pushed closed again to await its next finder- we are guessing that finding it might actually be the easiest part as judged by its size!

Although the real-world battery life has not yet been determined, a single coin cell for memory retention and a 9V battery used to drive the circuit and for latch release lasted through a full month of testing without any issues. Battery life could be extended almost indefinitely with a simple solar cell and rechargeable battery setup, but this would also obviously increase the likelihood of vandalism and/or theft.

We can imagine many different applications for such a device as-is including automated door lock  mechanisms and even access control to things such as the controls on a computer case.  It should also be fairly easy to increase the security by stringing multiple words together into a password or by instituting a “time out” period after a certain number of incorrect guesses.

Let us know of any other applications or build variations in the comments below and make sure to see how it all came together in the short videos after the break.

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