PMD update - WiFi(SAP), Bluetooth & Battery

🔘The SpacerLabs " Particle Matter Detector - PMD" was last updated here on 📅17 June 2025. Since then Soft Access Point (SAP) 🛜WiFi ( websockets server ) & Bluetooth versions have been developed, also powered by an internal 🔋battery.

WiFi & Bluetooth versions have the same appearance

A 🕸webpage has been designed, using HTML, CSS & JavaScript, specifically for the new 🛜WiFi SAP option. But the 🕸webpage User Interface ( UI ) for the STN ( Station ) option has also been revised to include status information about the internal🔋battery.

WiFi SAP version webpage on a phone's browser

The SAP 🛜WiFi version has no internet 🖧connection - see top of above image. So the online libraries used for the chart📈 plotting and background image in the STN version are not accessible by the SAP version.

The UI of the Bluetooth version is the Spacerlabs custom app "PMD_Viewer" for a Bluetooth enabled Android📱device.

App opened on a smart-phone🖁

Both the WiFi & Bluetooth versions have an internal re-chargeable battery🔋 permanently connected as a power source. The 🔋battery is a Lithium-Ion Polymer ( LiPo ) 3.7V 620 mAh type. Therefore these two PMD versions can be used for a limited time, in a hand-held or stand-alone manner, without the need for an external power source and connecting cable. Battery charge level 🪫information is displayed by the UI. The 🔋battery is recharged in-situ via the micro-usb socket.

 

The latest version of the 🗐'PMD User Guide' can be downloaded 🔗here. 🔳

PMS5003, colour display, BluetoothⓇ & cloud

🔘The project involving the 🪴Plantower 🗼PMS5003 digital Particle Concentration Sensor, described in the previous post on 8 April, has progressed further with the addition of embedded firmware using an  ESP32 microcontroller development board, a colour display, and BluetoothⓇ or Wi-Fi options.

The display is a colour TFT touch sensitive display with resolution 240 x 320 pixels, ( see image below ), last used on 5 January 2023.

Version with display using prototyping board 

Particle number per 0.1 litre ( ppdl ) of air and density ( ug/m^3 ) for various particle diameters Ø in microns are displayed. The "Air Quality Index  - AQI" ( 0 to 500 ) is derived from the PM2.5 density figure.  The "Quality" label which is assigned ( GOOD, MODERATE etc ) depends on the AQI. This is the method in common use internationally to quantify air pollution 😷 due to particulates. The touch-sensitive 'buttons' near the lower edge of the display give full control of the various modes of operation of the PMS5003. Some modes are initiated by sending instructions to the PMS5003 by serial data, and some are hardwired.

The ESP32 has a built-in BluetoothⓇ Low Energy, ( BLE ), module. The particulate matter data and mode functions as described above are available using the BluetoothⓇ version and the SpacerLabs custom Android App, "SpacerLabs PMD_Viewer vn.nn", on a compatible mobile device 📱having BluetoothⓇ enabled.

App user interface opened

Ubidots is a cloud hosted repository for measurement data. It was featured in this blog before, on 29 February,  then being used with the AQM device. The ESP32 also has a built-in Wi-Fi module. So a version of the firmware including Wi-Fi functionality was written, enabling the PMS5003 measurement data to be uploaded to the cloud.

PMS5003 Ubidots dashboard - ( click to enlarge )

An 'Air Quality' device, i.e., the Plantower PMS5003 Particulate Matter Sensor', has been added to our Ubidots dashboard together with several new widgets for displaying the particle measurements. A similar exercise was carried out with Thingspeak cloud; see also 18 February 2024. Search for channels by user ID spacerlabs to see the result.

The serial communications interface ( see 8 April 2024 ) is still retained, and is a common feature of all versions.