VCC pins usage for several sensors

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ajocius
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VCC pins usage for several sensors

Post by ajocius » Mon Mar 23, 2020 7:53 pm

I am using ESP32 with micropython code to read sensors data (mainly DHT22 and DS18B20 for temp and humidity). Both sensors that I mentioned use pull up resistor between data and VCC pins. Let say I want to connect 10 sensors (combo of above) to one ESP32. Can I use same VCC pin and 10 pull up resistors between that single VCC pin and 10 different data pins on 10 sensors? Or is it not a good practice? If this is bad practice, what solution do I have?

I see that my ESP32 (LOLIN32) has several 3V pins. Are those "independant" or just are there for convenience?

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jimmo
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Re: VCC pins usage for several sensors

Post by jimmo » Mon Mar 23, 2020 10:17 pm

Yep that's fine.

The issue you'd run into is if your pullups were too strong (i.e. low value resistance) and you were sinking too much current in them. But if you're using 10k, that's at most 3mA if they're all shorted to ground at the same time.

Generally the 3V pins are all the same net and just duplicated for convenience. The Pyboard does this too.

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