It’s a bird, it’s a plane, it’s a … solar dice?  Actually, it’s an example of a sensor node in the Internet of Things (IoT).  And this sensor node reports orientation to a host, so you always know which side is up as well as when it is rolled.

What’s so special about this dice?  Well, it operates with just those 6 solar panels (1 of which are usually covered up by whatever surface the dice is sitting on) and it is fully autonomous.  It figures out when it is rolled and it decides to transmit that piece of critical data to the host.  The ultra-low power design inside allows perfect operation from such a small power source and consumes just 2.36 µA of current in standby operation.

The on-board CC430 draws just a handful of µAs in its low power modes, while the TPS62740 power supply consumes just 360 nA when operating.  Energy for the actual work of detecting movement (through an accelerometer) and transmitting this data to the host (via the 868-MHz radio band) is harvested from the solar panels and stored in a small 330-µF capacitor.  Ultra-low power is at the heart of this system.

Of course, the solar dice is just an example of a sensor node in the IoT.  But with this technology, anything is possible.  Temperature, pressure, motion, humidity, etc. can all be measured with different sensors and reported to a host.  The final applications are truly endless.  Comment to this post to let us know what interesting and life-changing sensor nodes you are designing!

Want to see the dice in action?  Check out the video, "Conquering the Internet of Things Solar Dice Demo." 

Want to see the ultra-low power design and use it as a starting point for your next IoT project?  The design files can be found at "Solar Dice: A Sensor Node" Reference Design: PMP9754.