66% or better

Getting the lead out of the Arduino runtime

mhvlib_arduino_efficiency_runtime

Ah, the Arduino.

Love it or hate it, there’s no denying that part of its accessibility comes at the expense of speed and efficiency. We honestly like the platform as well as all of the others out there, because we believe that everything has its proper place and purpose. The crew over at Make, Hack, Void think that the Arduino dev boards are well and good, but that the core of the Arduino runtime could use some improvement.

They have taken it upon themselves to dig deep into the code and make some of the improvements that many advanced Arduino users have been clamoring for. Their MHVLib is an efficiency oriented runtime library which works on all AVR microcontrollers, whether they be standalone uCs or Arduino-branded hardware.

They have changed the way that the Arduino handles pin and port information, as well as how object and buffers are allocated in memory. Their code still relies on an Arduino-style bootloader, though they recommend Optiboot since it’s about a quarter of the size of the Arduino version.

There’s a complete list of what has been implemented available on their site, and you can grab the code via their GIT repository if you want to give it a try yourself.

Spamming a label printer with #cookiehammer

[John] has always loved stock ticker machines. These machines are highly collectible, so short of finding one that wasn’t hurled from a Manhattan skyscraper in 1929, a stock ticker is out of reach for the casual enthusiast. There is another way to get a stock ticker-like device though: hack a label printer to print out stuff from Twitter.

The build is really quite simple. A Dymo thermal label printer was modified to accept standard 2.25″ point of sale receipt paper. Now that the printer can shoot out line after line of text, [John] wrote a little bit of Ruby code using a Twitter API, RMagick for graphics processing and a Dymo printer driver.

Every 30 seconds, the code does a Twitter search for a specific hashtag and prints those tweets. #cookiehammer was the first thing that came to mind, so it stuck. Right now there’s a few tweets for #cookiehammer, but we expect [John] will have to put a new roll of paper in his printer fairly soon.

It may not be as informative as a stock ticker machine, but we think [John]‘s twitter printer build sure beats watching CNN. Check out the walk through after the break.

[Read more...]

Incredibly cheap upcycled cargo bike

diy_lastenrad_cargo_bike

What has two wheels, is made from five different bikes, and can carry all of your stuff for miles and miles on end?

[Paul Blue’s] DIY Lastenrad, that’s what. (Google Translation)

A Lastenrad is a cargo bike where the load sits in front of the rider rather than being towed behind. [Paul] wanted one for hauling things around town, and rather than buy one, he built one of his own. One thing we particularly like about this build is that the bike borrows parts from five other bicycles that were in various states of disrepair. That kind of re-use is something we can really get behind.

[Paul] estimates the total build cost to be under 50 Euros, which is fantastic considering how useful his Lastenrad is. After logging about 100Km on the bike, he says that it handles quite well, and that even when fully loaded it is extremely easy to make his way about town.

Continue reading to see a video of the bike’s first test ride.

[Read more...]

Hacking SPOT personal satellite tracker to pass more information

For less than $100 you can buy a little tracking module that will upload your location to a satellite. But you’ll only get latitude and longitude information. [Natrium42] spent some time reverse engineering the hardware, and the communications protocol, to allow custom data to be transferred using a SPOT module.

The flat fee for the hardware includes a one-year service plan allowing you to tack your device on the SPOT website. [Natrium42] started poking around in the transmitted data packages, and figured he could push custom messages like altitude data if he had some way to encode it as a valid latitude/longitude package. He found that location data is transmitted as two sets of three bytes each. The four least significant bits of each set get rounded by the server, leaving a total of 40 usable bits between the two data sets. He wrote encoding and decoding functions that will allow you to transfer whatever information you want.

So what is this good for? To get the process working he removed the MSP430 microcontroller from the board and is using his own replacement. So you can transmit GPS data from the onboard module, your own module, or sensor data for anything you’re able to hook up the to the replacement uC.

Make Your Own GPS Receiver!

GPS receivers may be available for well under $100 these days, but what’s the fun in buying one when you can build it yourself? According to [Andrew], the creator of this device, he was inspired by Matjaž Vidmar who developed a GPS receiver from scratch over 20 years ago. His article can be found here and includes some nicely hand-drawn diagrams as well as a lot of theory.

However, [Andrew's] article is a bit more up-to-date and features plenty of theory itself. He explains how he built his four-channel GPS receiver, able to track four satellites at the same time. This is the minimum number of satellites needed to track your position using such a device.

GPS technology is quite incredible, and the amount of soldering as well as the understanding of the theory behind it required to build such a device is astonishing. Interestingly (sadly?), it seems we are beyond the time of LORAN hacks, but if you have an old one to share, be sure to send it in! For something a bit easier, maybe one could try making a GPS “cateye” to track what your pet does all day!

A sunrise clock for those cold, dark winter mornings

sunrise_alarm_clock

For most of the working world, the onset of autumn and winter in the Northern hemisphere means one thing – waking up well before the sun rises to get a start on the daily grind. [Brent] from Freeside Atlanta knows that routine well and decided to build himself a sunrise alarm clock in an attempt to wake himself more naturally on those dark mornings.

He bought an assortment of LEDs in varying colors including blue, red, yellow, and white, along with a few UV diodes for good measure. His goal with this array of LEDs was to simulate the natural colors of the sunrise, rather than simply slowly brightening the room. The clock uses a DS1307 RTC to keep the time, and an Arduino is tasked with lighting the LEDs about 25 minutes before it’s time for [Brent] to wake up.

He says that it seems to be working pretty well, gently waking his body before the clock radio kicks in. It certainly beats a loud buzzer!

Weekly roundup 10/1/11

In case you missed them, here are our most popular posts from the past week.

Our most popular post was about a Chinese man who is attempting to build an octocopter that he can fly around by pairing motorcycle engines to propellers. There were a considerable number of comments on this one!

Next we have a post about a project where a 12-series PIC is used with a single inductor to create a working RFID tag.

Our third most popular post was [Bertho's] tutorial about capacitive sensing. This is his entry into the Dangerous Prototypes 7400 Logic competition so you’ll really get to see the nuts and bolts of how this type of sensing works.

Next is a post that is about a pretty unique lathe made out of concrete. If you have the weight capacity in your workspace, this could be a nice addition to your tools.

In fifth place is a post about [Eric's] second revision of his word clock that tells time in German!