ESP8266 Community Forum

- Tue Dec 28, 2021 7:04 pm #93193 Hello,

I know nothing about electronics. I only learned about micro-controllers, Arduino, etc. a couple of weeks ago.

I just received the Senseair S8 CO2 sensor and am waiting for the NodeMCU CP2102 kit that includes a SSD1306 OLED.

This article doesn't show to combine and power a CO2 sensor and an OLED display.

Should I use those:
OLED VDD → NMCU VIN
Senseair G + → NMCU VU
?

Thank you.

- Fri Dec 31, 2021 6:58 am #93211 While powering up from the USB, you can either connect your CO2 sensor's positive to Vin or VU.
As for the SSD1306, it's better to connect the VDD pin to the 3V3 pin of the NodeMCU. Because, though in general SSD1306 can run from 3.3V to 5V, some SSD1306 OLED displays cannot stand more than 3.3V in the VDD pin.

- Fri Dec 31, 2021 10:55 am #93213 Thanks much.

Yes, it looks like that OLED uses 3,3V.

What about ground? Am I correct in understanding I should daisy-link the three parts in a closed loop?

- Sun Jan 02, 2022 3:23 pm #93238 That NodeMCU board has four GND pins (along with one Vin and three 3v3), so I'll just connect each element to its own voltage and GND.

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