smôl Environmental Peripheral Board

The smôl Environmental Peripheral Board brings three low-power environmental sensors to the smôl modular ecosystem: atmospheric pressure, humidity and temperature (BME280), VOC air quality (SGP40), and ambient light (VEML7700). All three communicate via I²C and are optimised for ultra-low-power applications.

smôl boards stack together using 16-way 0.5 mm-pitch flexible printed circuits (FPCs), creating a compact, low-current sensor platform ideal for wildlife tracking, discrete long-term monitoring, and remote environmental sensing.

Onboard Sensors

• BME280 – Pressure, Humidity & Temperature
  • Temperature: 0°C to 65°C (full accuracy), -40°C to 85°C (operational)
  • Humidity: 0–100% RH
  • Pressure: 300–1,100 hPa
  • Current: 340 µA typical (measuring), 0.1 µA sleep
  • I²C address: 0x76
• SGP40 – VOC Air Quality
  • Output: Raw value (0–65,535 ticks) or processed VOC Index (0–500)
  • Reliable VOC detection in under 60 seconds
  • Current: 2.6 mA continuous, 34 µA idle
  • I²C address: 0x59
• VEML7700 – Ambient Light
  • Range: 0.01 to 167,000 lux
  • Resolution: 0.005 lx/ct
  • Current: 45 µA operating, 0.5 µA shutdown
  • I²C address: 0x10

Specifications

• Interface – I²C (all three sensors)
• Dimensions – 40.6 × 10.7 mm (1.60 × 0.42 in)
• PCB Thickness – 0.8 mm
• Interconnect – 16-way 0.5 mm-pitch FPC (smôl standard)

Resources

• smôl Hookup Guide – Assembly, stacking, and getting started
• Schematic (PDF)
• Hardware Design Files (GitHub)
• BME280 Datasheet (PDF)
• SGP40 Datasheet (PDF)
• VEML7700 Datasheet (PDF)