Arduino Uno powered with 12V 2A adapter

Hello to y’all,
I’m a semi-complete noob when it comes to Arduino. I have been thinking about this project for a while and I can’t figure out (mostly because of my lack of knowledge on this particular subject) how should I get it to properly work. So, the idea is I want to interface an Arduino Uno with the following parts:

  1. Lcd 20x4;
  2. Hc-05 Bluetooth module;
  3. Mq-5 Gas sensor;
  4. Dht11 temperature sensor;
  5. Rtc Ds3231 module;
  6. Three buttons;
  7. Two leds;
  8. An active buzzer;
  9. Water level sensor.

Problem is, it’s not an option to power the whole thing (on the long run) via a Pc Usb port. I need it to be powered either from an adapter or a battery. The battery would be the last resort though, it is much preferred to be able to obtain a whenever-ready system, without worrying about batteries and such.

Is there a chance to get it to properly work with, let’s say, a 12V 2A adapter? Will the Bluetooth (which uses the Rx Tx pins) be a problem, given the fact I’m not powering the Arduino via Usb?
Again, I’m pretty much of a noob and I know it. What I’m asking is probably a stupid thing.

First you need to see what voltage your parts need. Then look at the current they take. It is likely that if you start with 12V then you will probably need a regulator to make the required voltages from the 12V.
Do not use the voltage regulator that is built into the Arduino because they can not supply very much current without overheating.

A switching regulator, sometimes called a Buck regulator, is more efficient than a linear regulator and doesn’t get as hot.

A gas’s sensor takes a lot of current with the heater in it, and it needs to be on for two day before it can deliver a stable reading.

The adapter should be fine. The USB is connected to the Arduino 5V via a diode. When you power the arduino with an outside source the diode is reversed biased input effectively isolating your laptop power from the external power supply. It is important the grounds be connected. The D+ and D- voltages are referenced to ground, not a power supply. Using a small buck converter (less than a dollar from china) to supply your accessories.

denis662:
Is there a chance to get it to properly work with, let’s say, a 12V 2A adapter?

Unfortunately, no.

An Uno can only deliver about 100mA to power the sensors before the onboard 5volt regulator eventually overheats and (periodically) shuts down. The MQ-5 alone (highest user) is already using 160mA.
An external 5volt buck converter should be used to power the sensors and the UNO (on the 5volt pin).
Or use a supply with a lower voltage, like 7-9volt.

denis662:
Will the Bluetooth (which uses the Rx Tx pins) be a problem, given the fact I’m not powering the Arduino via Usb?

Another no.
Pins 0,1 (RX,TX) are permanently connected to the USB<>Serial chip.
Using them will usually give problems.
Better to use “SoftwareSerial” on different pins.
Leo…

Thanks y'all for the quick responses!

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