Sensing of temperature, humidity, and pressure in a MEMS remote aerial payload Undergraduate student: Matthew Nakamura PI: Assistant Prof. Joseph J. Brown jjbrown@hawaii.edu Office: 808 956 7081 Department Office: 808 956 7167 Web: https://me.hawaii.edu/people/brown/ Department of Mechanical Engineering, UH Mānoa

Q: How can we directly sense environmental conditions in air column? A: MEMS environmental sensor payload with independent power and data transmission. Mobile power: 9V battery Base station Payload

8-week Design-Build-Test cycle 8/31 project start 10/10 operational electronics 10/18 casing prototyped, operation in lab 10/25 field operation One undergraduate student, <$100

Bosch BME280 Environmental Sensor $20+shipping 1.8 µW when active Temp: -40 to + 85 °C Pressure: 30 – 110 kPa Humidity: accuracy to ±3% RH Size: 2.5 x 2.5 x 0.95 mm https://www.bosch-sensortec.com/bst/products/all_products/bme280 https://www.amazon.com/Adafruit-BME280-Temperature-Humidity-Pressure/dp/B013W1AJUY/

Data Handling and Transmission Arduino Nano microcontroller 1.4 W at full power $22 + shipping Transceiver NRF24L01, Nordic Semiconductor 37.2 mW when in use 2 MBps data rate Clear line of sight needed 2.4 GHz channel $12 + shipping https://store.arduino.cc/usa/arduino-nano https://www.amazon.com/Longruner-NRF24L01-Wireless-Transceiver-Compatible/dp/B016PP62QO

Combined System Total mass incl. battery: 114.53 g Dimensions 10 x 6.5 x 2 cm Volume: 130 cm3 Combined System Microcontroller Sensor Transceiver

Unpackaged base station Transceiver NRF24L01, Nordic Semiconductor Arduino Uno microcontroller Direct connection to computer USB

Live remote sensing operation

With 3 toy drones, not quite enough load capacity

Flight Test 10/25: Enough Capacity, Some Data Hiccups

Other sensor systems can be similarly implemented or added. Conclusions In 8 weeks we prototyped and operated a mobile environmental sensing payload. Other sensor systems can be similarly implemented or added. Shrink footprint by consolidating electronics, sensors, and packaging, and by device miniaturization.

Materials integration from fundamentals to applications This work brought to you by: UHM Micro/Nano Lab Asst. Prof. Joseph J. Brown, Ph.D. https://me.hawaii.edu/people/brown/ Department of Mechanical Engineering University of Hawai‘i at Mānoa Materials integration from fundamentals to applications Applied Research Themes Freestanding nano-thickness structure. Interfaces: Structural, fluid, electromagnetic Microdevice engineering Nanomaterial-based fabrication Further reading: US Patent 9919921, issued March 2018. J.J. Brown et al. Nanotechnology, 2016, 27, 475504. N.T. Eigenfeld, et al. Advanced Materials, 2014, 26, 3962. Acknowledgments: Applied Research Lab, UH Mānoa Micro/Nano Group members Mechanical Engineering Department Marvin Young for connection to ARL Thermoacoustic transducer made with 34 nm thick nanobridges.