Choosing an Arduino board for many sensors

Projects General Guidance
1

Hello,

Im trying to create a weather station that has 4 sensors, DHT11 (for humidity and temperature), BMP388 (for pressure and altitude), SEN0162 (UV sensor) and SEN0394 (for air quality). When trying to read the data sheet of each and seeing how they connect to an Arduino I realized some of the sensors are meant to connect to the same pins, my main question is can I for example plug pin A4 into a breadboard using a wire, and then have a line on my breadboard that connects more than one sensor to A4 or does it not work that way and each sensor needs its own SDA and they can't all be connected to one? If the way I explained earlier doesn't work, does that mean I need to look into different Arduino's other than the uno that might have more than one SDA built into them, or should I get more than one Arduino Uno.

This is going to be my first time using an Arduino for my uni project so I'm not experienced with them at all, just trying to figure out how to connect everything together through the data sheets given before blindly ordering stuff and then realizing it doesn't work the way I thought it does.

I was also wondering what's the black piece that you can put batteries into and then plug it into the DC power jack of an Arduino called. I was planning on using this so that the Arduino can be portable.

2

This is so you can TEST each device and learn how it works. Your final pin assignments are going to be based on your entire system.

3

So after testing each one individually will I not need to connect them to SDA anymore, and each sensor can be connected separately to any pin?

4

Do you understand how SDA works? You can connect them all to the SDA pins as long as you follow the rules.

5

No I'm not sure how SDA works, can you send me a list of the rules or redirect me to where I can learn them.

6

SDA is one of the wires on the I2C bus, to which you can connect several sensors at the same time. Tutorial here

SPI is another bus, accommodating several sensors.

7

Thank you very much, I now understand It slightly better and know how I can connect them all, as I was reading I saw that the one thing that matters in order to connect them all is that they don't have the same address, how do I check each devices address. Also I wanted to ask since you may know, what's the website people use to try to plan out their projects before building them, I see some people post their schematics when asking for help on the forums.

8

There is an Arduino program called I2Cscanner or I2CAddressScanner that will report the address of all the devices on the bus, and it is a good idea to use that to check whether I2C communications are working.

However, you should learn to use each sensor individually, and make sure you understand how it works. In that process, you should learn the address, or you can look it up in the sensor data sheet. Many devices have several selectable addresses.

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