Power delivery issue for our human following robot project

Question

We are very new in the game of robotics and we are dealing with a power delivery issue for our motors.

We are using two 12V DC motors to give motion to our robot. We are using the L293D motor driver to control the motors.

But motors are not receiving enough power so that they may give enough torque. I measured the power output to the motors and it is 3.7V.

For power we are using an 9V DC battery. We are using an Adriano UNO board as our microcontroller.

Full list of parts used:-

1. Ardriuno UNO
2. 9V battery
3. L293D motor driver
4. UV sensor

Now how can we deliver addition power direct to the motors using the L293D motor drivers. Please help

Code: https://github.com/pantharshit00/robo

Answer 1

It would be nice to know more about your robot. I've built robots in that range, and can make some suggestions.

First, if you're using a 9v battery such as the ones used in smoke detectors, you need a better battery. These just don't put out enough current to run everything a robot requires. I'd suggest a set of 6 AA batteries in series. This will provide you with the same voltage, but much more current.

Second, test the L293D motor driver by connecting the Arduino to the motor driver and motor and the power batter. Program the Arduino such that the pins will set the motor running at full speed with absolutely no PWM. Then edit your question to show the voltage across the motor.

Third, I believe that the Arduino Uno uses 5V logic, but I'm not absolutely sure that there isn't a 3v3 version of it.

Fourth, when putting together a robot, it's best to do one system at a time, get that working, and then add a new system. In this case, I'd suggest getting the motors working, and only then add the UV sensor.

Fifth, when asking a question, it's a good thing to provide links to everything necessary. It's even better to include these things in the question. It would be nice to have a schematic of the circuit to see if perhaps the pins are hooked up correctly. Not all the Arduino pins work the same.

I may have given too much information. I think that the main problem is the 9v battery.