HAT is a three-letter acronym (TLA) for hardware attached on top: the terminology used for a hardware specification for add-on modules for the Raspberry Pi model B+. With a HAT, no soldering is required, so the module simply plugs onto the Raspberry Pi. Taking advantage of this design concept and the popularity of the Raspberry Pi, Avnet has introduced an Indoor Air Quality (IAQ) Sensor HAT.

Based on Renesas ZMOD4410 IAQ sensor platform, the sensor HAT accelerates product designs requiring IAQ measurements. It provides an evaluation, development, quick-prototyping and proof-of-concept tool for the rapid development of commercial, industrial, and heating, ventilation and air conditioning (HVAC) products that employ an IAQ input.

The on-board, calibrated ZMOD4410 sensor measures the concentrations of total volatile organic compounds (TVOCs) from parts-per-billion to parts-per-million and can estimate equivalent carbon dioxide (eCO2) levels for greenhouse gases. These important indicators for monitoring indoor air quality are electrically and chemically (gas) tested with lab calibration data stored in each sensor’s built-in nonvolatile memory. The module’s sense element consists of a heater element on a silicon-based microelectromechanical systems (MEMS) structure and a metal oxide (MOx) chemiresistor.

In addition to the IAQ sensor, the HAT includes a Renesas HS3001 high-precision relative humidity and temperature sensor as well as software-controlled status LEDs.

Using a pre-compiled test application built with Renesas’ proprietary licensed algorithms that is included with the HAT and runs on the Raspberry Pi operation system, the IAQ HAT can measure TVOC and eCO2 out of the box. Called the AES-RHSEN-ZM44-G, it is available in the Americas from Avnet for $49.95.