Is it okay to power the Arduino UNO and two DC motors with a 9V battery?

Using Arduino Project Guidance
1

Sorry for asking a simple electronic question but I'm a newbie in electronics.

I am currently using Arduino UNO and L293D motor driver to drive 2 DC motors.

The Arduino UNO is powered by the USB port of my computer and the 2 DC motors are powered by a single 9V battery.

I am going to make my project mobile so I cannot use the USB cable as power supply anymore. Would it be okay to connect like the below image? Any disadvantages?


from: Controlling speed of DC Motors using ArduinoHardware Fun | Hardware Fun

2

Those batteries do not have very much current capability and do not last long. They are all but useless in driving motors.

No comment on the setup as it is a Fritzing physical layout diagram and not a schematic.

3

Grumpy_Mike:
Those batteries do not have very much current capability and do not last long. They are all but useless in driving motors.

No comment on the setup as it is a Fritzing physical layout diagram and not a schematic.

What are the good way to power the Arduino and the motors?

Separate power source for them?

4

The problem with the 9v battery is the low capacity. This means that it is not able to supply sufficient current or won't last long.

What to use depends on what you actually want to do with the project. 9v made up of AA cells will work. Make sure you power the Arduino via the Vin if you use 9v or more. If you use 12v, it is better to drop it to 5v via a switch mode regulator. Or drop it to 7v and feed it into the Vin.

Weedpharma

5

samcheng92:
What are the good way to power the Arduino and the motors?

Start with a battery suitable for the motors - a LiPo rechargeable - with the correct charger. If the motors operate at 9V, then perhaps a 3-cell battery.

This will provide enough voltage to power the regulator of the Arduino.

If on the other hand, you are only going to use two LiPo cells, then you need a 5V buck-boost regulator to power the Arduino from them at its "5 V" terminal, or use a separate battery such as 3 "AA" alkaline cells.

If the motors really are lightweight, then you might use a pack of "AA" alkalines according to the motor voltage and a separate pack as before, to power the Arduino.

I won't comment on whether the L293D is suitable for driving motors from batteries.

6

Thank you for the above comments.

If i use 6 x AA cells, can i just replace the 9V battery as in the diagram to power both the Arduino and the motors? Or I have to power them using separate batteries?

7

can i just replace the 9V battery as in the diagram to power both the Arduino and the motors?

No because 6V is not enough to power the Arduino's regulator through the Vin connector, you need at least 6.5V for that.

8

Grumpy_Mike:
No because 6V is not enough to power the Arduino's regulator through the Vin connector, you need at least 6.5V for that.

6 x 1.5V AA battery should be 9V?

9

I recently learned Fritzing has a schematic section. In the future, post from the generated schematic and it will make it easier for others to see how things are connected.

Alkaline batteries don't generally supply as much current as a good rechargeable battery. NiMH or LiPo cells are often good batteries for these sorts of projects.

10

"post from the generated schematic"
Have you seen the generated schematics? They are terrible!

11

CrossRoads:
Have you seen the generated schematics?

No I haven't.

There goes that idea. I'll stop suggesting it.

12

They can be just about OK but it takes a lot of effort and normally people don't bother and it is worse than useless.

13

samcheng92:
6 x 1.5V AA battery should be 9V?

Grumpy's abacus has flat batteries! :slight_smile:

Weedpharma

14

No it was my slide rule that had the flat battery.

15

Hi guys, I have decided to use a battery holder with 6 x 1.5 AA cells as it is easy to get.

Just one more question:
Should I use the 6 x 1.5 AA to power the Arduino and a 9V battery to power the two motors
OR
Use the 6 x 1.5 AA to power both the Arduino and the two motors?

1 Like
16

Use the 6 x 1.5 AA to power both the Arduino and the two motors

1 Like
17

Grumpy_Mike:
Use the 6 x 1.5 AA to power both the Arduino and the two motors

Then I cannot use the DC 2.1 power jack as I have to use the breadboard to supply power for both Arduino and motors..

18

I don't see how that follows, you make a lead to do what ever you want.