coniferconifer / air-bento Goto Github PK

Hi,
I am not very good at the electronics subject. I read the readme.md and I do not get few parts.

GY-21 board with SHT21 has 5V SDA/SCL pins , use FET 3.3V-5V level converter to connect to ESP32 I2C bus.

I checked the documentation and it looks it can work fine with 3.3V, so why you did you use 5V + level converter here?

Second thing regarding GP2Y1014AU0F:

Vo output goes up to 3.7V, so Vo is clipped by shotkey diode 1N5819 to protect GPIO33.

I checked "Dust sensor -> wiring", but how does this work? Should not be the diode connected in serial - I mean between V0 and GPIO33? I assume that the Shottky diode should drop the 3.7V to something like 3.3V? Alternatively could the level converter be used here instead?

The photos and documentation are very helpful, however could you please add a wiring scheme? It may be a hand draw. Alternatively I can recommend a fritzing software to make a digital one.

PS: I am really curious, because I am building a similar project - an "indoor air station" with following sensors:

• MH-Z14A for co2
• dust GP2Y1014AU0F (the wiring scares me) or PLANTOWER PMS5003 (seems very easy, power 5V, logic 3.3V - serial protocol, but it consumes the serial pins which gives best results from MH-Z14A)
• BME280 for Temperature Humidity and Pressure (it seems to be too 3.3V)
• MQ-4 for methane (long term plan)
• MQ-9 for carbon monoxide (long term plan)
  and some LCD + online monitoring (I uploaded data to google spreadsheet via ifttt hook)

See my repos: ESP32-pms5003 , ESP32-MH-Z14A with LCD

Best regards,
Rafal