How Low Can You Go?

April 9, 2011 by Jason Komp 29 Comments

That’s exactly what [Kenneth Finnegan] figured out with his original investigation into low powered MSP430-based circuits. He was able to keep a count-up timer running off of 20F worth of capacitors for over 10 weeks. Although quite impressive by its own merit, many people left comments that questioned whether similar results would be seen in a circuit with functionality more advanced than simply incrementing a single digit on an LCD. Well folks, [Kenneth] has stepped it up again with this ultra low power LCD clock.

The biggest challenge in creating this clock was finding an efficient way to drive the 28 LCD segments off of the limited number of pins on his MSP430G2231 chip while still having open pins for button inputs as well. An ICM7211 LCD driver is definitely up for the task (with a few clever modifications to drive the auxiliary characters such as the center colon), but requires 8 pins to drive it. A standard 74HC595 latching shift register brings this number down to a more manageable number of 3 total pins.

Once completed the total current consumption was found to be around 12μA – low enough for a claimed run-time of approximately two and a half years from the 3V 200mAh CR2032 coin cell used. If true, a set of standard AA alkaline cells in series as found in many clocks would run this little circuit for decades.

Stick around for a short video after the break and make sure to check out the original blog entry for schematics and the complete source code!

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Power-sipping MSP430 Mini Alarm Clock

April 4, 2011 by Mike Nathan 12 Comments

[Markus] had a TI MSP430 sitting around from the LaunchPad kit he bought a while back. He didn’t know what to do with it, but eventually decided that it would make a great miniature alarm clock.

He added a shift register to the mix in order to drive his 7-segment LCD display, using two of the MSP430’s output pins in the process. Four more pins were tied to the display’s cathodes, while the remaining two pins are connected to push buttons which register user input.

He crammed the clock’s logic as well as an alarm tune into the chip’s scant 2KB of memory space, literally occupying everything up to the last available byte. The clock is quite a power-miser, using just 2 µA in standby mode. According to [Markus’] calculations, that should enable the clock to use one set of batteries for 10+ years.

While this isn’t the first MSP430 clock we have seen, it certainly is the smallest and most simple. Stick around to see a quick video of his clock in action.

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Printable Gripping Rover Is Wristwatch Controlled

March 29, 2011 by Mike Szczys 4 Comments

[Lars Kristian Roland] is using a wristwatch to control this rover. The bot itself is a utilitarian build with a gripper based on this Thingiverse project. As you can see in the video after the break, it’s got variable speed control based on accelerometer data from a TI ez430 Chronos wristwatch.

The watch connects to the bot wirelessly thanks to a CC1110 development board which relays communications to the on-board Arduino through a serial connection. It looks like it’s a bit of a bother to make slow and precise movements using this setup, but this can probably be changed by tweaking how accelerometer values are interpreted (using a non-linear equation would allow you more control at low speeds without sacrificing top speed for the motors).

Because this is using the same RF hardware that the IM-ME does, we can’t help but wonder if the CC1110 development board could be swapped out for an unused IM-ME dongle?

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Header File Brings Arduino Sketches To The TI Launchpad

March 9, 2011 by Mike Szczys 31 Comments

[Chris Hulbert] is making it easy for Arduino users to program MSP430 chips with a header file that allows you to compile Arduino sketches for the Launchpad. This makes sense, as the growing number of Arduino sketches available, and the low cost of the TI Launchpad make for a good bedfellows. It’s really wasn’t that hard to make this happen, although you’re not going to find support for all of the Arduino functions just yet.

At the time of writing, [Chris] has just 51 lines of code committed to the project. It provides macros for setup(), loop(), delay(), pinMode(), pinBit(), digitalWrite(), and digitalRead(). You’ll notice that one of the most important parts of the header file is that it disables the watchdog timer for the user (a stumbling block for many MSP430 beginners). It’s an interesting solution, but to be truly useful we’d want to see hardware integration with the Arduino IDE. That, as well as the rest of the Arduino functions are at the tips of your fingers. Get coding and submit your push requests to [Chris] for inclusion in his repository.

[Thanks Chris]

Debugging MSP430 Using Eclipse

February 24, 2011 by Mike Szczys 8 Comments

[Springuin] just posted a tutorial about debugging MSP430 projects using Eclipse. He read our feature about debugging under IAR, a proprietary IDE which TI offers as a code-limited freebie with the TI Launchpad. In that writeup we wondered if anyone would put together a tutorial using open source tools like DDD and GDB to make debugging easier for those that choose to use operating systems other than Windows. Even though he didn’t directly use those particular packages, this should work just as well.

Eclipse is a popular IDE for many different languages like C, C++, Java, and others. We’ve already seen it used to develop for the TI Evalbot on Linux systems. [Springuin] is using the Java-based IDE on a Windows system, and this is the first time we recall seeing directions on using an open-source alternative for programming with the TI Launchpad under Windows. That being said, the only real Windows specific parts are the steps necessary for communicating with the programmer. Since this method uses MSP-GCC and msp430-gdbproxy, it should be easy to do this under Linux as well. Use our tutorial to set up those tools if you haven’t already, then follow this one for a setting up and debugging in the Eclipse environment.

Reverse Engineering A Mobile Phone E-paper Display

February 24, 2011 by Mike Nathan 6 Comments

msp430_epaper_display

While e-paper is common among e-readers, there are very few, if any phones other than the MOTOFONE that exclusively use an e-paper display. [Steve] had one of these phones sitting around and thought it could be used to build a low-power clock. Since the bistable e-paper display can retain the currently active content even when power is removed, he would only need to update the clock once a minute, when the time changed.

Unfortunately for him, very little publicly-available documentation exists for the display controller Motorola used. To get an idea of how the display was driven, he had to sniff the SPI communications between the processor and the display. Once he had the basic commands down, he spent quite a bit of time figuring out how to activate the different segments of the display, due to what seems to be a rushed design process on Motorola’s part.

Now that [Steve] had reverse-engineered just about everything, he connected the phone to a TI MSP430 to drive the display. He programmed the LaunchPad to serve as a basic clock with great results, as you can see in the video below.

If your interest in e-paper hacking has been piqued, be sure to check out our previous e-paper coverage here.

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Blinky Headgear

February 21, 2011 by Mike Szczys 4 Comments

[Everett Tom] added some blinking LEDs to his visor while honing his PCB design skills at the same time. He started with the TI eZ430-F2013 for prototyping the blinking circuit along with its mode toggle buttons. Once this was worked out he used BatchPCB (a low-cost professional board fab option) to manufacture a board. The final design hosts an MSP430 F2013 microcontroller as well as the voltage regulator circuit that draws power from the 9V battery that hides inside the head band next to the board.

You guessed it, video after the break.

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