Wall ward and Serial Monitor/Plotter

Projects General Guidance
1

Hi guys!
I checked a lot of posts over this forum but unfortunately, I didn't completely find the answer on my question yet so here it is:

I would like to power 5 different MQ sensors (MQ3, MQ4, MQ5, MQ6, and MQ7). Each of these sensors has a heater so the current consumption is around 200mA and to be able to achieve so high current I need an external supply.

What I did so far is that I removed the 117-5 chip (Voltage Regulator) from my Arduino and directly welded (+) and (-) (I used an old USB cable). Then I connected the remainings of a USB cable to the wall ward over my mobile chargers adapter to the wall ward (My adapters outputs are 2A and 5V). After plugging I checked the voltage of 5V pin on my Arduino and the output was 5.1 V. So far so good.

Now, my question is: How can I receive my sensors readings since I use external power? Thank you so much and kind regards

2

A schematic would be a very useful piece of information at this point, even if it is hand drawn.

You can always power the arduino directly to the +5V pin (with a regulated 5V supply) and then not have to remove the voltage regulator.

You will also have to make sure all your sensors and arduino share a common ground

3

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html .

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Can you tell us your electronics, programming, arduino, hardware experience?

Thanks... Tom... :slight_smile:

4

Well...it is honestly a very simple circuit. You can see it on this link: IMG-20190731-200403 hosted at ImgBB — ImgBB
The difference is that on this picture are just 2 sensors while in reality there are 5 but just to make it easier to see I put 2 here. And where you see 2 cables (from where voltage regulator should be), these are going on a 5V 2A adapter and to the wall ward. I am really noob in electronics so i'd b really grateful for your help! All the best

5

If you want the get the reading in Serial Monitor, you still need the USB cable between the Arduino and the PC.

It probably would have been easier to bring the 5V, 2A supply into the breadboard +/- and then just have a pair of wires from the breadboard to the arduino +5/GND than to remove the voltage regulator.

The voltage regulator only comes into play if you use the barrel jack or Vin.

6

So you are telling me there is no way to have serial monitor/serial plotter when you use an external power supply? :confused:

7

Which of a dozen or so different Arduino boards?
And it's wall wart, like a wart on your wall. :slight_smile:

8

It is Arduino Uno R3 Rev3 ATMEGA328P. Yeah my bad...Wart it should be :smiley:

9

greg92:
So you are telling me there is no way to have serial monitor/serial plotter when you use an external power supply? :confused:

The Serial Monitor really has nothing to do with how you power your circuit. If you want to capture data that you are printing to Serial, you will need to use the USB port to do so.

If you want to send the data to the cloud or communicate with bluetooth or over ethernet, then you can do that but it will require a shield and/or other circuitry to do so.