On the 2018 Symposia on VLSI Technology and Circuits, the University of Michigan presented the Michigan Micro Mote. This tiny device is the result of a study led by David Blaauw, a professor of electrical and computer engineering. The project was a collaboration between the University of Michigan and Mie Fujitsu Semiconductor Ltd. Japan and Fujitsu Electronics America Inc.
More information about the study can be found in a paper published under the name: A 0.04mm3 16nW Wireless and Batteryless Sensor System with Integrated Cortex-M0+ Processor and Optical Communication for Cellular Temperature Measurement.
A Computer or a Senor?
The Michigan Micro Mote is tiny. The device is in the shape of a cube with sides which measures just 0.3mm each. This makes it almost a tenth of the size of the previous world’s smallest computer, a sand-grain sized device that was unveiled by IBM back in March 2018.
Although the scientists designed the Micro Mote to be used as a precision temperature sensor, the device could my some measures be defined as a computer. The tiny device is equipped with a processor, photovoltaic power system, RAM, wireless transmitter and a receiver which communicates through the pulses of light.
The device is powered from the base station which beams light to the beach and it also sends data back to the base as light through a transmission LED.
Because the Micro Mote is too small to have conventional radio antennae, it receives and transmits data with visible light. A base station provides light for power and programming, and also receives data.
The light from the base station and from the transmission LED can induce currents in its tiny circuits. “We basically had to invent new ways of approaching circuit design that would be equally low power but could also tolerate light,” Blaauw said.
The bone of contention is whether the device can indeed be labelled a computer since the device loses its programming and data is wiped away when the device runs out of power.
Precision Temperature Monitoring
The Micro Mote “converts temperatures into time intervals, defined with electronic pulses. The intervals are measured on-chip against a steady time interval sent by the base station and then converted into a temperature.
As a result, the computer can report temperatures in minuscule regions—such as a cluster of cells—with an error of about 0.1 degrees Celsius”, states a report by the University of Michigan.
According to researchers, it is believed that the technology of the Micro Mote can be used in extremely small environments, such as inside the human body. One example would be for cancer detection and treatment, as cancer cells are believed to be hotter than healthy tissue.
Multiple Industrial Applications
The utility of the technology has the potential to be much wider than just oncology. The sensor system is very flexible and could be reimagined for a variety of purposes, including biochemical process monitoring, oil reservoir monitoring and audio and visual surveillance.