DIY cellphone

Here’s an interesting concept. Lets make a kit to build your own super simple cell phone. Thats basically what a group at the MIT media lab is proposing with this prototype. Consisting of an SM5100b GSM module and a 1.8″ 160×128 pixel LCD screen on a very basic board holding some buttons, this thing is pretty bare bones. Barely any features aside from sending/receiving calls. It does have caller ID though. At$150, it isn’t really that competitive compared to the phones you’d get from your provider, but it is just a prototype.

We particularly like the laser cut flex areas for the buttons on the front.

[Thanks Paul]

Dead-bug Arduino is still breadboard ready

Here’s a no-PCB Arduino that doesn’t obscure the DIP footprint of the AVR chip. It’s built on an ATmega88 chip, and includes a programming header, reset button, a couple of filtering caps, and an LED. This is modeled after the Lilypad hardware, and fits nicely on top of the plastic case of the microcontroller, allowing it to be used in a breadboard or DIP socket. You can see a walk through of the components in the clip after the break.

We don’t really need most of the components on top of the chip (especially the status LED on the SCK line), but there are several things that we like about this. First off, the programming header is extremely nice. We could see this coming in handy for prototyping where you don’t want to add a header to your final design. Just use a chip socket, and this chip while you’re developing firmware. Once everything is dialed in, program a naked chip and swap the two. The same goes for the reset button, which is nice when working on firmware but may not be necessary in your final design.

This is quite an old project, and we’ve actually seen a successor to it. This is Rev. 2 and we looked in on Rev. 7 back in March. That one is a full Arduino, but the circuit board has no substrate.

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Prototyping the Bulbdial clock

Evil Mad Scientist posted a story about what went into developing the Bulbdial clock. We think the Bulbdial is one of the best pieces of kit out there for many reasons; using colored shadows for each hand is a brilliant idea, the design is clever and uses a low parts count, and the concentric rings that make it work also add to the aesthetic. But after seeing the original wood prototype it had crossed our minds that developing those circular PCBs isn’t the easiest thing to pull off. To save on board cost, the first run didn’t have the center routed out, but rather used almost-touching holes drilled during manufacture and finished by hand during assembly. They also go on to discuss the use of Charlieplexing to reduce part count and the search for a suitable diffuser for the clock face.

Surface mount breakout boards

We got a hold of some DS3232 RTC chips in a 20-pin SOIC package. We’d like to have one that is breadboard compatible for easy prototyping but when we searched for SOIC20W breakout board artwork we found none. We used Eagle to design our own and you can see the finished product above which we made using the toner transfer method and cupric chloride.

You’ll find the artwork after the break in case you need to make your own breakout board some day. If you know of surface mount breakout board artwork that is freely available please leave the link in the comments for future use, or send it to us on our tips line and we’ll add it to the post.

Incidentally, the DS3232 is the same as the DS3231 used in the ChronoDot but with the addition of some SRAM. We’ll let you know if we come up with an interesting project for it.

Update: We added 28 SSOP to DIP artwork submitted by [Paul Dekker]

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Light up your limbs

Here’s a Christmas tree project we can get behind. The “tree” itself is made of twisted pairs of insulated copper wire.  At the end of each pair a surface mount LED has been soldered between the two conductors.  All of the wire limbs converge into a 4×4 matrix. One tree uses a prototyping shield and an Arduino, the other tree is just using an ATtiny2313 microprocessor. Take a look at the twinkling tree in the video after the break.

This artful creation uses one color of LEDs.  We’d love to see future improvements that incorporate multiple colors, enhance the fading effects, and perhaps add some interactivity such as pulsing to an inspiring rendition of Chestnuts Roasting on and Open Fire (which, consequently, is called “The Christmas Song“).

Continue reading “Light up your limbs”

Tube prototyping station

[Gio] enjoys using vacuum tubes in his projects. He designs the circuits using a CAD program but was finding that there is no substitute for actually building a prototype before heading to a final design. To make this process easier, he built his own tube prototyping station.

At the top of the board he’s got three different sizes of tube sockets with the pins from each wired as common. The nine pins from the sockets break out to a terminal strip where they can be interfaced with a solderless breadboard. For added versatility he’s included terminals to tap into some RCA jacks, as well as a 100 kOhm variable resistor. We’d bet this is not something that you can find ready-made, but it sure does look a whole lot better than a workbench full of components alligator-clipped together.

Centipede shield design contest

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Our friend [Garrett Mace] from macetech has finished a prototype of a new shield which allows the Arduino (or any other microcontroller with I2C) to add 64 digital I/O pins using only 2 of the analog pins. Currently he only has a few pre-production boards, and rather than selling them he is throwing a contest to win them. The contest is looking for people who have a specific project in mind that could use the centipede, and on Friday November 13th he will pick his favorite two. To submit an idea, just head over the Arduino forums and post an idea complete with details and relevant schematics, etc.

We will be sure to follow up with the winners of the contest, as well as let you all know when the Centipede Shield makes it into production.