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64 Articles

How Low Can You Go?

April 9, 2011 by 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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Birthday Gift Is A Constant Reminder Of Impending AARP Membership

March 22, 2011 by 16 Comments

birthday_countdown_timer

Sometimes milestone birthdays can be a bit depressing. 30 is rough, and 40 tougher – but 50…that’s a big one!

[Ryan’s] uncle is going to be turning 50 shortly, and in the interest of good-natured fun, he has constructed a handy birthday countdown timer for his uncle, lest he forget (or tries to avoid) the big day.

The device displays the amount of time left before his uncle’s birthday, playing an audio clip of “Don’t fear the Reaper” when the clock strikes 00:00. This is accomplished by using the MSP430’s internal clock to keep time, while also interfacing with a Nokia 3310 LCD panel to display the countdown timer. The music is provided by the circuit board from a greeting card he gutted for the project, which was wired to the LaunchPad in order to be triggered at the right moment. Everything was crammed inside an Altoids tin, as you can see in the picture above.

Though not overly complicated, it’s a fun little project, and we’re hoping his uncle gets a big kick out of it. Once his birthday has come and gone, [Ryan] plans on converting the piece into a permanent desktop clock for his uncle.

Header File Brings Arduino Sketches To The TI Launchpad

March 9, 2011 by 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]

Reverse Engineering A Mobile Phone E-paper Display

February 24, 2011 by 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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Learn To Debug Msp430 Chips Using IAR

February 15, 2011 by 7 Comments

If you haven’t done any debugging with microcontroller programs [Kphlight] posted a follow-along guide for debugging MSP430 chips. You can see above that he’s using the TI Launchpad and has chosen the free (but code limited) IAR Embedded Workbench that is one of the IDE’s that TI provides for the kit. The example builds a Pomodoro timer with just five LEDs and one resistor. You’ll flash the code to the chip, step through each line of the firmware, and learn how to manipulate register data during code execution.

It’s a great primer for the uninitiated, and we’d love to see one using open-source tools like DDD and GDB. If you do write one, don’t forget to send us a tip about it. If you want to give open source a try with this hardware check out our own tutorial.

LaunchPad MIDI Synth

February 13, 2011 by 6 Comments

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[NatureTM] sent in a writeup for the MIDI synthesizer he recently built using a TI LaunchPad. The construction is pretty simple overall, consisting of little more than the MSP430, a handful of resistors, and an optoiosolater. Of course, a MIDI controller is required, but he already had that on hand.

Once the MIDI data is read from the optoisolator, his code takes care of the rest, adjusting the square wave sound generator to get the proper note. He does mention that since the synthesizer is monophonic, special care is taken to ensure that simultaneous notes are processed properly. You can route all of the sound into a single speaker, but he used the optoisolator to send the sound data to multiple LaunchPads instead, resulting in a fun little MIDI quintet.

He provides code and plenty of video on his site, but keep reading for a sneak peek of his synth in action.

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Launchpad Serial Morse Code Transmitter

February 11, 2011 by 11 Comments

LaunchPad-Serial-Morse-Transmitter

LaunchPad dev boards from Texas Instruments are cheap and easy to program, making them a great Arduino alternative if you can do without some of the bells and whistles. [ech0s] put his to good use by constructing a Morse code transmitter with dual operating modes. The transmitter can not only encode and transmit messages entered in a terminal client, it also allows the user to send messages by manually operating the key switch. Inspired by the high altitude balloon transmitter we featured last summer, this project uses similar components for signal amplification and transmission. Text can be entered in a Putty terminal window, which then is encoded into Morse by the MCU before transmission. At the moment, the speed of the radio transmission is about 15 WPM, which is reasonably quick. Even though his system performs quite well [ech0s] has some improvements planned, including having a proper PCB built as well as some software tweaks to improve buffering and bandwidth. Be sure to check out his video of the transmitter in action after the jump.

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