SnifferBuddy is a puck-shaped device designed for indoor grow environments, monitoring key ambient conditions such as temperature, humidity, VPD, CO₂ levels, and light status. It uses a SCD40 (or SCD41) sensor and a photoresistor for precise measurements within the grow tent.
The readings are transmitted via MQTT, enabling seamless integration with workflows such as Node-RED, Home Assistant, or custom applications. This package includes support for storing readings in a local DuckDB database for data analysis and post-processing. A GrowBase is needed to store the data.
The system operates entirely on your local Wi-Fi network, ensuring no data is sent to the Internet.
Deploy multiple SnifferBuddies to gain a detailed, nuanced view of the entire grow space.
Opening up the SnifferBuddy
reveals its components:
- ESP8266 Wemos Mini D1
- SCD40 or SCD41 sensor
- Resistor
- Photoresistor
- 3D-printed enclosure
- thin wire
Building a SnifferBuddy requires basic soldering skills. For detailed instructions on how to assemble it, check out the Build Guide.
With the enclosure assembled and components installed, it's time to set up and configure the firmware. This is covered in the Firmware Guide.
The Data Collection Guide covers how to setup the data collection process.
There are a variety of tools available to explore the data. As an example, a marimo notebook is included in the examples folder. First, install pip install marimo. Then run marimo edit examples/play_with_sniffer_data.py to open the notebook. I copied a version of the duckdb database from my GrowBase to the examples folder to have data readily available to play with.
To run the marimo notebook on the Raspberry Pi, install marimo and copy the play_with_sniffer_data.py notebook to a directory on the Raspberry Pi. In the same directory, start marimo with the --host flag. marimo edit --host 0.0.0.0 /home/pi/snifferbuddy/notebooks/play_with_sniffer_data.py. The URL will have the IP address of 0.0.0.0 when you click on the link. Replace 0.0.0.0 with the IP address of the Raspberry Pi. The notebook should now be running on the Raspberry Pi.
Refer to sections 1.1–1.3 of the SCD4x datasheet for details on the accuracy range and expected lower and upper bounds for CO2, relative humidity, and temperature measurements. For example, if the temperature reads 70° F, the actual value can range from 68.6° to 71.4° F.
The SCD4x datasheet (section 3.6) details the On-Chip Output Signal Compensation mechanism, which adjusts for temperature inaccuracies caused by self-heating from the sensor and nearby electronics. This temperature offset is initially set to 4°C. It can be adjusted within a range of 0°C to 20°C to address additional environmental factors, providing a means to calibrate the sensor for greater accuracy.