Glass Jar Sensor Package Development

Glass Jar Sensor Package System

Design and Research Project

Snapshot Overview

Project Dates: May 2022 through December 2023

Technical Skills Used:

Circuit Design & Analysis
PCB Design
Sensor Integration
Inductive Charging
Soldering
Arduino Programming
Electronics under Vacuum Conditions

Project Outcome(s):

Successful development of sensor packages for use in monitoring the seal of glass mason jars.
Package was designed and tested to be fully contained within a vacuum-sealed regular mouth mason jar.
Sensor package was designed, tested, and deployed to collect data continuously throughout short term and extended test durations (up to one month of uninterrupted operation).
Package designed and tested to collect humidity measurements as low as dew points of about 25 C.
Successful development of a multi-component power system for maintaining consistent power output to sensor package within sealed jar for extended periods of time.

A combination of inductive power pairs and an uninterrupted power system (UPS) associated with each jar was chosen and tested to provide a consistent power output during testing.

Compact Design

The development of compact sensor packages was the second portion of a two-part research project meant to quantify the moisture leakage into glass mason jars over time. The reasoning for this overall research project was to understand the consequences of dry-room failure in the storage of materials with irreversible reactions to moisture. To this end, each complete sensor package (including power and data recording systems) needed to be able to easily fit into regular mouth glass mason jar. Another requirement of the project was the ability to record data consistently for test periods of up to a month.

In order to determine the amount of humidity leaking through the mason jar seal, multiple measurements were recorded from within the jar. The primary sensor of the package was the MS8607 sensor, a temperature, humidity, and pressure sensor. Pressure within the jar was a beneficial metric that was used to verify the absolute humidity (a function of relative humidity and temperature) recorded within the jars.

Similarly to the climate chamber control system, the sensor package functions from an Arduino Nano Every. The Arduino Nano Every provided a small form factor with an adequate amount of computing power. Data was recorded using a combination of a real-time clock (RTC) module and MicroSD card module. These two modules allowed for precise timestamps with each measurement. The RTC module proved very beneficial in its ability to wake the Arduino up from sleep at set time intervals. With the ability to have the Arduino sleep and wake-up, the team was able to minimize power draw during our long-term tests.

Long-Term Power

Most regular mason jars have a mouth diameter of about 2.375 inches. This size constraint meant that large capacity batteries would be unrealistic to power the system. Over multiple months of sourcing battery supplies, I realized that we had the ability to use wireless power for our packages. After determining that powering the sensor packages with inductive coil pairs was a viable solution, I sourced a small-form universal power supply that could act as our backup power, if the wireless connection was interrupted. The inductive power coils took an input voltage of 12V and functioned transferring 5V 2A between the coils.

The image to the above was taking during some of my final testing of the power system before mounting the transmitter coils into the climate chamber. The image below shows the sensor systems placed on their respective transmitters within the chamber. A plate of clear acrylic was used to separate the jar receivers and the chamber transmitters to the necessary transmission distance. The acrylic also acted as a waterproof protector for the transmitter coils.