Another wireless UV Radiation Meter

In the last post, ( 30 September 2020 ), I described my UV radiation meter. That version had Bluetooth (BLE) enabled. Since then I have made a second * version of the meter, but this time having WiFi functionality instead. It is based on the same hardware ( SI1145 sensor & Heltec WiFi Kit 32 module ) as before. As the WiFi Kit 32 module ( see 02 August 2020 ) has both integrated Bluetooth and WiFi, the only changes needed have been to the firmware. I have used an identical enclosure; so the physical appearance is also the same. However, different information is now being displayed on the OLED display.

In use, WiFi typically has a communication range greater than BLE. The meter can be configured either as a Client station connected to an existing network's WiFi router, or as a stand-alone WiFi Access Point; the latter being the more suitable for outdoor use. The meter hosts a web-server, so that a web-page with the UV index measurement can be displayed by connecting to its IP address using a browser on a pc, smart phone, or other WiFi enabled devices etc.

 

A simulated reading displayed on a smart phone

The image above shows the UV Index measurement displayed in a browser. I should point out that the reading was made under controlled laboratory conditions during testing. A background UV Index reading made in an indoor environment would typically be about 0.02 !  

I am calling it the "Spacer-Labs" UV radiation sensor after the location of my laboratory.

* Actually I have also made a third version without any wireless connectivity at all.      

Wi-Fi and Bluetooth with ESP8266 & ESP32

Several years ago I began experimenting with Wi-Fi using modules based upon the ESP8266 family of devices manufactured by Espressif Systems in Shanghai. They are microcontroller chips with built-in 2.4GHz Wi-Fi capability. Development boards using these chips are readily available at very low cost from many different suppliers. At first I used the basic ESP8266-01 incorporating the ESP8266EX chip, and then progressed to boards with more functionality ( I/O, serial comms, ADC etc ) i.e., the NodeMCU-12E using the ESP8266MOD. I was thinking about some IoT ( Internet of Things ) applications. Although I made some gadgets, nothing was actually being controlled remotely. Eventually I moved on to other activities.

However, my interest in this topic returned recently after discovering the successor to the ESP8266, namely the ESP32, ( 32bit, 240MHz clock & more memory ), with both built-in Wi-Fi and Bluetooth ( classic Bluetooth & Bluetooth Low Energy, BLE, server & client ) capability; also development boards incorporating the ESP32 such as the NodeMCU-32S and some others including a video camera ( ESP32-CAM ) or an OLED display ( Heltec WiFi Kit 32 ). All these remarkable devices cost only a few dollars.

My collection of Wi-Fi & Bluetooth development modules

In the above image, left to right :-

NodeMCU-12E, Wi-Fi only.

NodeMCU-32S, Wi-Fi and Bluetooth.

WiFi Kit 32, Wi-Fi and Bluetooth, 128 x 64 px OLED display.

ESP32-CAM, Wi-Fi and Bluetooth, 2Mpx video camera, 4GB uSD card slot.

ESP8266-01, Wi-Fi only.

Perhaps I'll make a BLE server to notify a value from an unusual sensor; e.g., air quality, charged particles, UV, magnetic field. ( Obviously for my personal experimental use in my private capacity as a hobbyist. )

( I tweeted updates to this post on 5 August 2020 and 12 August 2020. Click on the link on the left ).