Iam making a line follower robot , the issue is coming when making motors run.The L239D module has 4 inputs pins ( to control two motors) , 4 output pins (to drive motors) , and 6 power pins (5v,5v,GND,GND,9/12V,9/12V) . I have used one 5v pin to connect it to ardunio 5V supply and one of the 9/12v pin to series of two 9v battery. The motors are running low and when it is on ground the line follower not able to move. I even tried 3 9V batteries in series to make up the voltage 9+9+9=27V but not helping. Any help Thanks in advance.

  • Is your motor being drived when you hold it in the means when it is not placed on the ground – Maaz Sk Oct 21 '20 at 5:06
  • yes , when it is in hand i do see it getting rotated but not on ground – Mokka Naresh Oct 21 '20 at 6:24

I guess using 9 Volt battery in parallel will do your work because if the motor is moving as you quoted above means it is getting the voltage but not enough current to drive it, please connect the 9 volt battery in parallel and it will work for you


9V batteries, assuming you mean the little PP3-size ones, can't supply the current needed for driving robot motors; they are intended for low-current applications.

Putting them in series will give you a higher voltage, not more current, and the higher voltage could damage something else in the circuit.

Assuming you connected everything correctly, including ground: you need bigger batteries. Even 6 AAs in series would be much better than using a 9V battery for getting your robot to move.

  • If i can connect 3 9V batteries in parallel, is that going to help! , as the current is the requirement. – Mokka Naresh Oct 21 '20 at 4:39
  • Have you tried batteries in parallel – Maaz Sk Oct 21 '20 at 6:28
  • It will help a little, but they will be empty very quickly. Make sure they are at about the same voltage before connecting them in parallel. – ocrdu Oct 21 '20 at 9:21

On your next try use a different H-Bridge, one with MOSFET outputs, you can have a voltage drop across the L239D of 2.4V. Measure the voltage at the motor and at your batteries you will see what I am getting at. You might want to try connecting the motors directly to the battery first to see if it will do what you want.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.