A portable exhaust fan with sensing and auto-shutdown function
Let's get rid of mushrooms growing in bathroom from now on!
- Avoid using AC adapter in a humid environment.
- The circuit is simple enough to fit in a waterproof plastic food container.
- Using a powerbank with low current shutoff function, the energy saving function can be simply implemented.
- Built-in EEPROM Datalogger mode, measure your environment and change your own threshold value.
- Could be built with DC-DC boost converter module LM2577 and generic 12V computer fans
- Select your own parameter to be record or detect ( change in #define )
- Easily set up the turn-on mode through a 4pin mode jumper
( Normal Mode / Serial debug on / Readout EEPROM / Clear EEPROM / Datalogger mode )
refer to the schematic below
Default Software Specifications
| Parameter | Units | Notes | |
|---|---|---|---|
| Arduino Board | Pro Mini 16MHz | - | 8MHz untested |
| Fan Refresh Cycle | 4 | sec | timer1 ISR |
| Data Logging Cycle | 60 | sec | timer1 ISR*15 |
| DHT Sampling Cycle | 1.5 | sec | needs >1 second |
| Size of Average Data Set | 10 | - | only record the average data |
To be done
- Adding a tiny I2C OLED (128*32) with sleep mode
- Adding capacitive sensing pads / slider for a non-contact input interface
- Adding a buzzer to notify when job is done
- A modern but simple interface that doesn't need much intelligence while using
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Schematic :
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Hardware :
Follow the schematic and my photos , you can make it easily. -
Software :
Open the sketch /software/AutoExhaustFan using the Arduino IDE- External libraries
- [Sketch] → [Iclude library] → [Manage Libraries] and search for "DHT"
- Select "DHT Sensor library by adafruit" and Click the [Install] button.
- Another library could be found in Arduino Playground - DHT11Lib if you want to import it manually.
After installing the library, click the [upload] button on the IDE then you're done!
Remember to use the datalogger function and re-define your own threshold value. - External libraries
