23 March 2023

Solar UV Radiation Meter๐ŸŒค

Frequent or prolonged exposure to high levels of solar ๐ŸŒž ultra-violet ( UV ) radiation can damage the human skin.
The SpacerLabs solar 'UV Radiation Meter' ( abbreviated UVRM ) provides a way to measure the radiation and display the result as the UV Index and UV Level. Informed decisions about appropriate precautions can then be taken if necessary. ๐Ÿ˜Ž๐Ÿค 
The UVRM is based on the Silicon Labs SI1145 'UV Index sensor', together with a 32bit micro-controller, blue 0.96" 128x64px OLED display module and power management system. The UVRM is powered by an internal 3.7V rechargeable Lithium battery, which can be charged in-situ via the micro USB connector. A custom 3-D printed blue & white hand-held enclosure gives the UVRM a smart appearance.
UV Index ( zero to 11+ with a resolution of 0.01 ), and UV Level are displayed according to the W.H.O definitions; Low, Moderate, High, Very High & Extreme. The SI1145 also derives a "Visible Light Index" ( VIS ) and an "Infra-Red Index" ( IR ). These indices are not displayed directly by the current versions of the UVRM.
UVRM displaying an indoor UV reading
Two main options have been developed allowing the UVRM to be used as a stand-alone device when extended battery life is important or the option of wireless connectivity using BluetoothⓇ.
SpacerLabs has developed a custom App called  "Light_Meter" to connect to the UVRM using BluetoothⓇ communications.
The SpacerLabs 'Light_Meter' App
Using one of the BluetoothⓇ versions of the UVRM with a paired and connected mobile device running the App makes it easier to view the data in some outdoor situations ๐ŸŒž. The VIS and IR indices are also exposed.
 
( W.H.O = World Health Organisation )
 

15 March 2023

Multi Sensor Air Quality Monitor

An inexpensive domestic 'Air Quality Monitor'  ( abbreviated AQM ) has been modified with additional sensor support, display module and 32-bit micro-controller.
The original AQM, ( made in China ), uses a Cubic PM1006 Particulate Matter sensor to determine the PMx ( x =  microns ) particulate matter concentration in the air and changes the colour ( green, yellow or red ) of an illuminated indicator accordingly. This feature has been retained in the SpacerLabs modified versions.
The modified versions measure PM1, PM2.5 & PM10 and, optionally, have either a CCS811 sensor or AHT20 sensor also fitted to provide TVOC & CO2 or temperature & humidity data as well. The measurement data are displayed on a blue or white 128x32 pixel OLED display. Firmware which controls the sensors and the display is uploaded to the micro-controller via a micro USB connector.
AQM version PM1006/CCS811
AQM version PM1006/AHT20 will be deployed in the kitchen where airborne particulate matter ( smoke ) and high humidity caused by cooking can be monitored.
AQM version PM1006/CCS811 is suitable for a workshop environment where CO2 & TVOC could be present, in addition to particulate matter.
A SpacerLabs App, called "Air_Quality", has been designed, so that the PM1, PM2.5 & PM10 measurements can be viewed on a mobile device, using BluetoothⓇ communication. The PM2.5 concentration value will change colour in the same way as the illuminated visual indicator on the original domestic AQM.
SpacerLabs 'Air_Quality' App
The AQM can be powered by a USB charger connected by a cable with a USB-C plug.
The micro-controller also has built-in wifi as well as BluetoothⓇ. This opens up the future possibility of integrating the multi-sensor AQM into a 'smart home' network.

TVOC  = Total Volatile Organic Compounds ( paint, solvents etc ).