## Project notes 2022-11-05 (Air quality prototyping)

The development of the code for the logging board has continued. It was fun having the flashing LEDs indicate the actual menu state, which is very useful. Still, it is not practical to tie up so many GPIO ports on the controller for this function.

 However, I was not ready to completely abandon its practical use. I found a better solution using a multicolor, digitally controlled Dotstar diod. I was delighted when the Unexpected Makers ESP32 TinyPICO's had them and included a practical library. Therefore, I have decided to replace the ESP8266 D1-mini with the ESP32 in the project. There are several advantages to doing so.

- The ADC resolution improves from 10-bits to 12-bits.
- Numerous ESP32 API functions will help improve the accuracy of the logger.
- The physical size is smaller with ESP32 TinyPICO. They can be purchased, for example, at Pimoroni and Adafruit.
- The ESP32 has the memory and speed to add code and new functionality as the project progresses.
- That may not be true for the initial (too small) display, but we will see. Of course, the project specification still needs to be defined.

I have to redo the calibration of the new implementation, which is why I'm prototyping. The cost is higher than the ESP8266, but it's worth the extra money. I claim that the solder fume extractor absorbs all the bad stuff; thus, I need to prove it. 

I have invested in Sinsirion's SGP40 air quality sensor, and I had a BME680 temperature/humidity sensor lying around. The latter sensor will improve the air-quality data. The latest pictured FR-2 prototype board helps generates test measurement data for the SD card.