Some part of DC motor move slowly

[syldun]

Hello everyone, my final year project is car controller using 2 modes which is by ultrasonic sensor & android apps. My problems are

1. When the first try everything works fine for ultrasonic sensor mode but after a few day later, one of my dc motor move slowly and sometimes not moving. I need to move manually then it moving but still slow but when it move reverse it worked. For the motor shield I'm using arduino uno combine with L293D motor shield.
2. How do I combine 2 different coding to 1 complete coding? As I mention above the car control by 2 modes.
   Thank You.

[Grumpy_Mike]

How are you powering he motors?
Using 9V batteries like a PP3 is a mistake beginners often use.

@syldun

How do I combine 2 different coding to 1 complete coding?

Take a look at this
Merging Code

[gilshultz]

Post an annotated schematic as you have it wired, showing all power and ground connections and power sources. "Technical" links to the hardware devices helps a lot links to azon and similar are sales no real technical information.

[syldun]

I'm using 2x 18650ithium battery 2000mAh 3.7V

[syldun]

This is circuit diagram taken from youtube

[TomGeorge]

Hi

@syldun

my final year project i

Do you know how to draw an electronic schematic diagram?
The picture you have posted, tells us very little.

Please post, hand drawn is fine, a schematic showing ALL power supplies, ALL component names and pin labels.

Thanks.. Tom...

[johnerrington]

..and a link to the motors you are using please

How to make a schematic you can post.

When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…

[Grumpy_Mike]

Can you take a voltage measurement across the motors when they are moving slowly please.

[gilshultz]

That is a nice picture but in no way should be confused with a schematic. I would assume since this is your final year you have some schematic drawing experience and or training. If not there are many good tutorials on line that will teach you how to do it.