Chill Your Phone For Longer Battery Life?

April 5, 2011 by 45 Comments

The first specs we look at when choosing a cellphone are the battery life numbers. We know that eventually we’re going to see performance loss, and [Dr. West] wanted to see if there’s a way to delay the inevitable. What he found is that ambient temperature affects the battery throughout its life. He set out to build a phone chiller to slow the degradation of the battery.

The research that he points to shows that at room temperature, a Lithium battery will lose 20% of its capacity each year. This seems like a dubious number so do share links to studies that state otherwise in the comments. Whether that 20% is right or not, the point is that cooling the battery will preserve it. With that in mind, [Dr. West] put together a pod that uses a peltier cooler and a heat sink to host his Blackberry while he sleeps. He figures he can reduce the capacity lost per year from 20% down to 14%. This of course comes at the expense of running that cooler every night (in addition to charging the phone when it needs it). But perhaps this solution will spark an idea that leads to a better one.

TI Adds Some Linux Support For Evalbot – We’ve Got Hardware Coupon Codes For You!

April 5, 2011 by 109 Comments

In case you missed it, Texas Instruments sells a little robot called the Evalbot as a development platform for ARM Cortex-M3 microcontrollers. Since its release we’ve seen a few hacks on the hardware; the image above is a proof of concept for developing for the device under Linux. We have criticized TI in the past for not natively supporting Linux with their IDEs. We’re not sure how it will play out, but they have added new software package options to go along with the hardware. You’ll notice on their PR page that there is now an option to use CodeSourcery. It is a trial of the full version, but at least it is a step in the GNU direction from their previous offering.

The Hackaday team has been talking off and on with TI about the hardware. We’re happy to say that they’ve been listening to the Internet community about their likes and dislikes; following various online groups that have sprouted up to talk about Evalbot projects. It sounds like they’re thinking about hosting a contest using the hardware. So maybe you want to get your hands on one so that you can familiarize yourself and hit the ground running if/when that contest starts. You’re in luck, we can help save you a few bucks.

The first time that Texas Instruments tried out a $125-off coupon code the deal got away from them. It had been meant for attendees of the ESC Boston conference. They honored the deals that went through before the proverbial run-on-the-bank got shut down. This time around they’re using serialized deal codes to limit the number of give-aways. We’ve got 200 of them just waiting for our loyal readers to use. One code will let you purchase one Evalbot for just $25 (instead of $150).

Please take a moment to decide if you actually want (and will use) one of these robots, and decide if you are willing to shell out the $25 to order it. You see, we don’t want this deal going to waste. If you decide this is for you, send an email requesting a code to:We’re all out! We’ll dish out the deal on a first-emailed-first-served basis. We will update this post when all 200 have been claimed.

We will not tolerate anyone gaming the system and so we reserve the right to disqualify any email submission for any reason in an attempt to maintain some semblance of fairness. Also… if you’re planning to pick this up just to resell it for cash you’re a loser.

[update: Those who emailed us requesting a code should begin receiving replies this evening or tomorrow.]

[Update 2: here is the specific bot you should be trying to buy. ]

Retake On A Wii Remote Controlled Balancing Robot

April 5, 2011 by 4 Comments

[Tijmen Verhulsdonck] built his own version of a Wii remote-controlled balancing robot. He drew his inspiration from the SegWii, which was built by [Ara Kourchians].

The body is built using one of our preferred fabrication methods; threaded rod makes up a rail system, with three sheets of hard board serving as a mounting structure for the motors, electronics, and battery. This does away with the 9V batteries used on the original SegWii, opting for a very powerful lithium battery perched on the highest part of the assembly. It uses an Arduino as the main microcontroller. That detects roll, pitch, and tilt of the body by reading data from a Sparkfun IMU 5 board (we’re pretty sure it’s this one). Check out the videos after the break. The first demonstrates the robot balancing on its own, then a Wii remote is connected via Bluetooth and [Tijmen] drives it around the room by tilting the controller. The second video covers the components that went into the build.

This is impressive work for a 17-year-old. [Tijmen] lists his material cost at $800 but since he’s Dutch this might not be a USD currency.

Continue reading “Retake On A Wii Remote Controlled Balancing Robot” →

Cocktail Cabinet To Be Proud Of

April 5, 2011 by 17 Comments

At a glance you might think it’s the real thing, but if you look closer you’ll see that The Distraction Contraption is an extremely well-executed cocktail cabinet recreation that hosts a MAME setup. [Sam Freeman] took pictures of the entire build process and has posted them, along with captions, as a Flickr collection.

The project started after some inspiration from this diminutive cocktail cabinet. He wanted his own version that was closer in scale to the coin-op versions that would have been found in bars a few decades ago. He designed the case to fit a 17″ LCD screen using Google Sketchup. From there, he cut out the parts and routed the edges. The controls feature buttons and joysticks, as you’d expect, but that red cap on the end works as a spinner. He tried out a few different ideas for this auxiliary control. He found that using LEGO gears to map the spinner’s motion to the axle of a mouse worked best. To give the plastic knob a better feel he loaded it with pennies to increase the mass, bringing momentum into play. The final look was achieved using wood-grain contact paper, and custom printed skins.

Atmega Analog Two Pack

April 5, 2011 by 7 Comments

Back in February, [ProtoStack] posted a pretty good tutorial on how to do Analogue to Digital Conversion on an Atmega168. Based on a bread board, the tutorial also shows the often forgotten low pass filter on the AVCC lines to ensure an extra stable reference and an analog input connection to a simple voltage divider as a study point.

Moving on into the micro controller, the registers you’re going to need to twiddle are laid out and explained in detail. Finally you’re shown how to put it all together in a software project that outputs the analog reading onto a standard character LCD.

But hold on! There is more. Just released is a follow up to that tutorial which adds on Analogue to Digital Conversion Interrupts on an Atmega168A. So if you’re sitting there looking at an Arduino and want to know more about what’s going on under the hood, these are a good place to start.

Redeye Printer Interface

April 5, 2011 by 6 Comments

This handy printer interface started out as a request on our very own forums when forum member [victorf] needed some output via thermal printers. He had scored a number of HP82240B thermal printers intended for use with HP calculators, but of course they used the somewhat arcane HP protocol first drafted in the 1960’s and needed some help.

Fellow forum member [wireb] started to look into it, found out it uses a standard 32KHz carrier signal, and started asking questions about its use. Grabbing a pdf of the manual he was able to find out all the details to what the printer was expecting in the form of communications.

After a few weeks, [wireb] was able to make a convenient, logic level serial to HP-IR adapter based around a PIC16F1824 who’s firmware supports 9600 8N1 or 2400 8N1 speeds, ASCII text, and the printer’s “advanced” graphical modes via escape sequences.

If you have not checked out our forums yet we suggest you do!

Retrofitting LCD Projectors With High-powered LEDs

April 4, 2011 by 56 Comments

highpower_led

[Devon] recently repaired a handful of Phillips LCD projectors which he was quite excited to use. The only problem is that he didn’t want to mess with replacing the bulbs after every 2000 hours of use at $100 apiece. He was pretty confident that he could find a better way to drive the projectors, so he disassembled them once more and started looking around for bulb replacements.

He figured that a high-powered LED would do the trick, so he ordered a handful of parts and went about his first retrofit. Using his oscilloscope, he found that the control board pulses the high voltage board when the projector is powered on, and continues to pulse a signal until the machine is turned off. At this point, the HV board powers down the bulb.

He created a small circuit using a PIC that is used to interpret the initial pulse from the control board as well as watch for the steady “heartbeat” pulses that occur while the projector is powered on. This board is used to control the driver board for the high-powered LED he purchased.

His bulb replacement works well as far as color fidelity is concerned, but is not nearly as bright as he hoped for. He has plans to source some far brighter LEDs or automobile HID lighting in the very near future, and we look forward to seeing if he can match the brightness of the original bulbs.