Power for DC Motor and Arduino

I just started my Arduino journey so please excuse any simple questions. I did some reading and some sample projects and now I am hoping to build a autonomous bot using ultrasonic sensors and DC motors.

I want to power the entire bot from a single power source. Other than sensors and Arduino uno board I purchased these components,

  1. Turnigy 1000mAh 3S 20C Lipo Battery Pack This has balance charger pin and +ve, -ve output pins.
    http://www.ebay.in/itm/Turnigy-1000mAh-3S-20C-Lipo-Battery-Pack-/201336561858

  2. 600RPM 12V DC geared motors No-load current = 800 mA, Load current = up to 7.5 A(Max)
    http://robokits.co.in/motors/high-torque-dc-geared-motor-600rpm

  3. Dual H Bridge L298N DC Stepper Motor Drive Controller Board Module
    http://www.ebay.in/itm/Dual-H-Bridge-L298N-DC-Stepper-Motor-Drive-Controller-Board-Module-for-Arduino-/111641359612?

  4. I also have a L293D MOTOR DRIVER IC from a friend

I just started the project and need your inputs,

  1. Can I power 2 DC Motors and Ardunio from the lipo battery?

  2. The lipo is 11.1V (3S) battery do I need to regulate the power to Arduino? If yes what should I use. I read somewhere that this is not needed and Ardunio has voltage regulators built in to supply 5V is that correct?

  3. How do I take power from the lipo to both Arduino and DC motor, it has only one output, mostly I will be using perma proto board and soldering the connections

  4. I have Hobbyking 2-8S Cell Checker with Low Voltage Alarm and planning to use it in the bot which will warn if I am discharging more than the rated voltage. Do I need any other lipo battery protection circuit?
    http://www.hobbyking.com/hobbyking/store/_18588__HobbyKing_8482_Cell_Checker_with_Low_Voltage_Alarm_2S_8S.html

Any other suggestions, inputs for this project?

Thanks a lot for taking time and answering my questions.

  1. Yes. Arduino might restart if there's a big current surge that drops the battery voltage so low that 5V cannot be maintained. Thus most motor projects recommend separate supplies.

  2. Arduino has built in regulator. Might get warm running from 11.1V (and higher when fully charged).

  3. Make/buy a splitter cable, power both in parallel.

warn if I am discharging more than the rated voltage.

rated current perhaps? taking voltage too low (overdischarge)?
Seems like a good starting point.

customize the alarm to sound

Don’t risk your model by flying on depleted batteries

I wonder if that would that be hearable if your plane/copter was in the air and some distance from you, wind blowing, leaves rustling, etc?

Thanks a lot for your inputs. One more noob question. So far I have used USB and barrel jack (not sure if that's what its called) to supply power to Arduino.

I am planning to use L298N H Bridge it has 5V output for Arduino. If I need to supply power to Arduino with this output which pin I should connect to in Arduino? Will it be 5V PIN? Can Arduino accept power through its pin? If yes I am guessing that I can't use the 5V pin to power other sensors right?

Sorry for the noob questions. Appreciate your help.

L298N requires two voltage supplies - 5V for the control logic, and the higher voltage that is supplied to the motors. It does not supply either one to other devices.
Be sure to connect grounds together.

CrossRoads:
I want to power the entire bot from a single power source.

In other words you want to make life difficult and potentially expensive for yourself...

Its not normally worth the hassle - but one approach is to derive the logic supply from
a DC-DC converter with a wide input voltage range from the motor supply. This allows
the motor to supply to be all over the place (it will be) and yet get constant power for the
logic and sensors. You can also bolster the input to the DC-DC converter with LC filtering
to remove the worst of the spikes and drop-outs on the motor supply too.

One of the main reasons its a bad idea in the first place is that your logic supply will
get unreliable as the main batteries run down, so your robot goes out of control. Having
a logic board supply with greater endurance than the motor supply is a very wise precaution.

And get a motor driver than can handle the full current of your motors, L293/8
is entirely inadequate.