Cats of Engineering - Mungo Jere

Here's Mungo Jere's photo for the Cats of Engineering layout at Adafruit.

Energy Scavenging WSN

Putting together all the pieces now. Here is a complete Open Source Hardware (OSHW) Wireless Sensor Node (WSN) that energy scavenges. Have a Peltier thermo-electric generator resting on top of a 20W wirewound resistor and scavenging the energy from the waste heat of that resistor.  The Peltier device then powers a Linear Technology LTC3108 chip (described here) which powers a wireless sensor node (WSN) that is built from a NXP LPC1114 MCU and a Atmel AT86RF212 800 MHz radio (described here).  The wireless stack is the Chibi stack (described here).  The WSN transmits data every 2 minutes, which gives the storage capacitor in the energy scavenger plenty of time to recover.  The sleep state of the WSN draws about 25 micro-amps and the wake state when polling the sensors and the radio on draws about 11 ma.  The radio is on for about a second every 2 minutes. 

Click on image to enlarge

 The peltier device generates electrical power proportionate to the heat flow through the device.  The power output can be increased then by blowing gently across the top surface of the peltier device which increases the convective heat loss on the top surface and increases the flow of heat through the device from the hot side where the resistor is generating heat to the top cool side where heat is lost convectively.

Energy Scavenging LTC3108 OSHW SSOP package version

Just finished testing the LTC3108 board with the SSOP package.  Works great!   More to come.

Having fun with Sparkfun Ultimate IMU

Just got my Sparkfun Ultimate IMU and it is performing flawlessly.  Next I plan some changes to both hardware and software but as it is, right out of the box, it's amazing.  The IMU (with a quarter for size comparison) is powered by a LiPo battery.   It uses an Xbee to link to the PC (IMU Xbee is on the underside of the board).  This is a 9 axis part, that is there's 3 axis accelerometer, 3 axis gyro, and 3 axis magnetometer (to help manage gyro drift).   Thinking of agriculture related applications amongst other things.  I'll comment more on my progress and the changes in other posts.  One idea I have is to redo this using roughly the same software but with a updated MCU, a LPC1343 Cortex M3 vs the  LPC2148 M7 that comes with it.  Also will add a SWD JTAG connection so it can be used with a debugger (the Sparkfun unit does not come with any connection for JTAG).  Want to add a version of Kalman filtering to improve the performance as well.  More on that later.

LTC3108 Eagle files and component library posted on github

I've posted the Eagle files and the component library for the LTC3108 breakout board (both DFN and SSOP) on my public github site, https://github.com/wa7iut