Single Chip micro-Mote (SCμM) is a crystal-free wireless device fabricated on a single die. It is designed for ubiquitous wireless networks with ultra-small wireless devices to realize the smart dust vision.
Single Chip Micro-Mote
Single Chip micro-Mote (SCμM) is a crystal-free, 2x3mm2 single-die solution for wireless sensor networks. It is the outcome of the Smart Dust project, targeting to pack an autonomous sensing, computing, and communication system into a cubic-millimeter mote (a small particle or speck) to form ubiquitous wireless networks.
To make the mote millimeter-size, SCμM has replaced the crystal reference used by most commercial radios with different types of resonating electronic circuits and utilized optical communication to program the mote. A printable battery and higher frequency communication (to eliminate the antenna) are currently under development for integration onto SCμM, making SCμM an independently-operated micro-mote.
Crystals are commonly used in clock systems to provide high timing accuracy at the expense of increased space, higher energy, and increased cost. To fit in a millimeter scale die, SCμM replaces the crystal with resonating electronic circuits which provide 4 clocks:
A 2 MHz RC oscillator for clocking the chip sending/receiving
A 20 MHz RC oscillator for running software on SCμM
A 64 MHz RC oscillator for clocking an Intermediate Frequency (IF) to easily tune the high frequency incoming signal (~2.4GHz)
A 2.4 GHz LC oscillator for generating a 2.4GHz signal
Communication with SCμM
SCμM is designed to run various communication protocols to build wireless networks. It is optimized to run Time-Slotted Channel Hopping (TSCH) based communication protocols, such as OpenWSN 6TiSCH protocol stack implementation.
The OpenWSN project has created a port to run 6TiSCH protocol on top of SCμM. For proof of concept, with this port, SCμM is able to synchronize to an OpenMote, a COTS device for wireless sensor network, and establish a 6TiSCH network.