RESOURCES
MSP430x20x1, MSP430x20x2, MSP430x20x3
Mixed Signal Microcontroller (Rev. D)
Texas Instruments, 2007
MSP430x2xx Family User’s Guide (Rev. E)
Texas Instruments, 2008
Ultra-Low Voltage Nanoelectronics Powered Directly and
Solely from a Tree, Carlton Himes, Eric Carlson, Ryan J.
Ricchiuti, Brian P. Otis, Babak A. Parviz,
IEEE Transactions on Nanotechnology, 2009
AUTHOR’S NOTE
The project described in this article was awarded the
third prize in the international MSP430 Ultra-Low Power
Design Challenge 2010 sponsored by Texas Instruments.
If you’d like to see a video of the winning project, point
your browser to www.designmsp430.com/displayVideo
.aspx?id=29e378ef-e65b-4e79-8dfa-91dc8e84dbe3.
interval to wake up the microcontroller approximately
every second, so most of the microcontroller’s time is
spent in Low Power Mode 3 (LPM3)
which reduces the power
consumption even further.
When the MSP430F2013 wakes
up, it displays the next counter value
from zero to nine in the LCD and
goes to sleep again. This process is
endless.
Next Steps
So, now you know how to
power an ultra-low power
microcontroller, by using the
bioelectricity supplied by the plants.
Unfortunately, since it’s necessary
to connect several potted plants
together in series to get enough
energy to activate the
microcontroller, this reduces its
practical use on a grand scale.
The minimum voltage necessary
to activate a transistor in the
current CMOS technology is
approximately 0.7 volts. However,
thanks to new developments in
energy harvesting technology, a new
generation of oscillator circuits are
emerging that are able to run from
0.3 volts.
Since the oscillator is the main
building block of a charge pump, it
may soon be possible to design a
circuit able to store that tiny amount
of energy for later use. It would then
be possible to power an ultra-low
power microcontroller with just one
plant instead of several. Now, that
would be a novel type of green
energy! NV
Carlos Cossio can be reached at
ccossio@hotmail.com.
I would like to thank Sonia Riveiro
for her assistance with this article.
40
September 2010
