Open Arduino-Based Environmental Sensor Package for COSMOS Nodes:

Design, Integration, and Real-Time Environmental Monitoring

Week 6 Updates

• Print preliminary enclosure CAD design
• Integrate MOSFET-based heater control for MQ gas sensors
• Expand environmental sensing capabilities with remaining sensors
• Integrate TEENSY 4.0
• Verify sensor functionality and update system schematic
• Explore Kicad PCB Editor

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Agenda

Humidity Test

Setup as of 7/2/26

MOSFET: A Type of Transistor

• MOSFETs are voltage-controlled transistors commonly used for electronic switching.

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• An N-channel MOSFET was selected to switch the MQ-4 and MQ-7 heater circuits.

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• Arduino digital outputs drive the MOSFET gate to control the heater duty cycle.

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• Programmable heater switching reduces thermal interference with nearby temperature sensors while maintaining gas sensor operation.

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N-Type MOSFET on the breadboard

Week 6 Progress

Temperature accuracy

• Investigated thermal interference between the MQ gas sensor heaters and onboard temperature sensors.

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• Implemented MOSFET-controlled heater cycling for the MQ-7 and MQ-4 to reduce enclosure heating.

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• Developed Arduino timing logic to collect MQ data after sensor warm-up while allowing enclosure cooling between cycles.

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• Scheduled temperature measurements during the final minute of the heater OFF cycle to improve measurement accuracy.

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Temperature Sampling Logic Validation

• Implemented timed temperature and humidity sampling.

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• MQ heaters remain OFF during the sampling window.

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• Serial Monitor verifies correct 10-minute sampling cycle.

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• Reduces thermal interference and improves measurement accuracy.

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Serial Monitor on Arduino IDE: 6/30

Thanks!

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