Home Radon Mitigation Monitor
2020-12-08 | By Andy
License: GNU Lesser General Public License Raspberry Pi
Reason for my project
Radon is an invisible, tasteless, and odorless radioactive gas naturally occurring in the soil beneath our homes and is prevalent across major portions of the USA and EU. According to the US Environmental Protection Agency, radon kills more than 21,000 people in the US each year and over 20,000 per year in the EU. Radon mitigation systems use a low power fan to create a vacuum under our homes to draw down the radon levels to reasonably safe levels. The radon fans are often in attics, crawlspaces, and basements where they operate silently forgotten for years creating a slight vacuum pressure under the house. However, if the fan should fail to create the proper vacuum, the home occupants will be exposed to radioactive radon, the leading cause of non-smoker lung cancer.
Overview of the Project
The project uses a low-cost Honeywell ABPMAND001PG2A3 (480-6250-ND) pressure sensor and a Raspberry Pi. It can be Raspberry Pi 3 or 4. You will also need either a prototyping breadboard or some wire and solder. This hobby project adds an additional layer of monitoring and data logging.
Required hardware
- ABPMAND001PG2A3 (480-6250-ND) pressure sensor available from Digi-Key
- Raspberry Pi, power supply, and SD memory card available from Digi-Key
Hardware setup
There are 4-wires to connect the pressure sensor to the Raspberry Pi:
- RPI 40-pin Honeywell ABP pressure sensor
- Pin 1 (+3.3 VDC) Pin 2 (Vsupply)
- Pin 3 (SDA1) Pin 5 (SDA)
- Pin 5 (SCL1) Pin 6 (SCL)
- Pin 6 (GND) Pin 1 (GND)
A silicon or plastic tube is also required to connect the pressure sensor to the radon mitigation pipe to sense the vacuum pressure. The plastic tube is inserted into the mitigation pipe by drilling a small hole the size of the tube's outer diameter. The plastic tube can be any length. It is recommended to keep the I2C wires (SDA1 and SCL1) fairly short. I kept the wires to under 3 feet in length.
Required software
After installing the Raspberry Pi operating system, I downloaded the software from GitHub:
https://github.com/BrucesHobbies/radonMaster
The source code is 100% Python. The program will send alerts when the radon mitigation fan vacuum/pressure changes and also can send daily, weekly, or monthly status reports through email. You can also monitor the vacuum pressure without sending the alerts directly on the Raspberry Pi. The daily, weekly, and monthly pressure readings can be plotted on the Raspberry Pi. What I noticed is that the vacuum pressure does change significantly on days with gusty winds outside. The program employs an algorithm to minimize false alerts.
This project was helpful to learn how to interface Honeywell TruStability Amplified Basic Pressure Sensors (ABP), I2C and SPI bus interfaces, Python, Raspberry Pi operating system, and interfacing hardware to the Raspberry Pi.
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