Indoor Air Quality sensor IAQ01

This repository contains all CAD files needed for making a Veles IAQ01 wired sensor, part of a family of Veles Smart Household sensors.

Basic properties

Measured values

• Carbon dioxide
• Temperature
• Relative humidity
• Volatile Organic Compounds (VOC)
• PM (particulate matter) [optional extension]

Connectivity

• RS-485 with Modbus

Power requirements

• Input voltage: 5 - 30 V DC

Status indication

Sensor has a RGB LED, which shows current air quality status on a continuos scale from red to green. Limits for this full green / full red are user adjustable. Indication can be also configured to non-continuos "semaphore" mode, using only 3 colors (green / yellow / red). Intensity of the LED can be set (or the LED can be disabled entirely).

Where to get these sensors?

We hope to be able to be to offer you these sensors in one way or another (fully assembled or some kits with PCBs and components). In the meantime, you can build one yourselves! You will need a bit of experience with PCB ordering, soldering, and flashing the firmware on STM32. Don't worry though, none of these require deep expertise. Also a 3D printer will come in handy, if you want some of those pretty enclosures. We suggest using white PETG - this makes the LED shine nicely through the front of the enclosure.

Project files

• Hardware
  • Schematic and PCB (KiCAD project) in PCB/iaq_wired_sensor.kicad_pro
  • PCB step model in PCB/Project_Outputs/3D_MODEL/iaq_wired_sensor.step
  • Gerbers for PCB manufacturing in PCB/Project_Outputs/GERBERS
  • Schematic exported as PDF in PCB/Project_Outputs/Schematic/iaq_wired_sensor.pdf
  • Interactive HTML BOM file in PCB/Project_Outputs/iBOM/iaq_wired_sensor_rev1_ibom.html
• Firmware
  • This is a STM32Cube IDE project
  • Uses a number of git submodules - clone this repo with --recursive or use git submodule update --init to get them
• Enclosure
  • FreeCAD project in Enclosure/IAQ_Sensor_Enclosure.FCStd
  • STL files in Enclosure/STLs
    • Printing tested on Prusa Mk2S and Ender 3
• Documentation
  • Datasheet in Documentation/Datasheet/IAQ_Wired_Sensor_Datasheet.pdf
  • Product flyer in Documentation/Product_Flyer/wired_iaq_sensor_flyer_rev1.pdf

Images

Veles Smart Household

This sensor is part of Veles Smart Household. Goal of this project is to create open hardware and software platform for measuring various quantities, not only related to indoor air quality:

• temperature
• humidity
• atmospheric pressure
• carbon dioxide (CO2)
• carbon monoxide (CO)
• volatile organic compounds (VOC)
• particulate matter (PM - dust particles)
• light intensity
• soil moisture

... and some more!

Sensors are connected either via RS-485 Modbus or wirelessly to central unit. Wireless sensors are currently in development. Central unit may be any anything that can read from the bus: any computer with RS-485 to USB converter (e.g. Raspberry Pi) or an actual PLC. Readout of the sensor is possible via Modbus: either using your own favourite application or using your Python package.

We want this to be community effort! Come help us make something great!

Other Smart Household repositories

• RHT wired sensor
• Python package for sensor readout and visualization (work in progress)
  • Can be installed using pip install veles

Further reading

If you need more data, check out the datasheet.

Modbus register cheatsheet

If you're here just to see the addresses for the readout, here they are:

Input Registers

Value	Register
CO2	30010
SHT4x	30011
RH SHT4x	30012
T SCD4x	30013
RH SCD4x	30014
T SHT4x SIGNED	30015
T SCD4x SIGNED	30016

Holding Registers

Value	Register
LED ON	40001
LED BRIGHTNESS	40002
LED SMOOTH	40003
CO2 ALERT LIMIT1	40004
CO2 ALERT LIMIT2	40005
SCD4x T OFFSET	40006
MODBUS ADDR	40007

Device Information Registers

Value	Register
VENDOR NAME	30010
PRODUCT CODE	30011
REVISION	30012
PRODUCT NAME	30013
SERIAL NUMBER	30014