DC motor

[picpicpikapika]

Hi,
I think I am going to use a pair of 9V battery to drive my car...actually I need it to sustain around five minutes...I think a pair of nine volt battery should be able to do that...for the connection, can I straight away parallel it, or I need to add any circuit components for safety precaution?
Thanks a lot...

[kl84]

Yes, you can parallel them. Usually it's okay to do so for the same type of battery, eg: NOT putting AA & 9V in parallel.

However, like shiyan mentioned, 9V battery is not suitable for this kind of application. I personally will use rechargeable AA batteries if LiPo is not available.

[picpicpikapika]

Hi,
Can I still use the voltage regulator 7805 to regulate lipo battery???...Is this battery too heavy for the mcu??

[sich]

Can I still use the voltage regulator 7805 to regulate lipo battery???

Of course. As long as the voltage doesn't exceed 7805's max Vin.

Is this battery too heavy for the mcu??

Heavy in term of weight? Depends on the size. There's smaller LiPo batt at 1100mAH, 7.4V, ~100g, 70mm x 33mm x 15mm.
Heavy in term of power? Not a valid statement in this case. Your mcu only takes as much current as it needs, no matter how much more the power source (eg: battery) can supply.

[picpicpikapika]

Hi,
I am thinking of using two power supplies, one will be a nine volts battery, i am using it to power up mcu, ir sensor and motor driver( I am using L293D motor driver to drive the motors), another one is four AA 1.5V batteries, I am using it to supply power to pin 8 of the motor driver(this pin is for the motor power)...

Is this ok??

Besides, I have tried to run my racing car...it is working but it can't go straight although the motor driver has supplied two same magnitude voltage to the motors...please give me some suggestion thanks a lot

[sich]

it is working but it can't go straight although the motor driver has supplied two same magnitude voltage to the motors...

This is quite common especially for Tamiya motors. Many factors contribute to it, eg: different motor's performance, gear friction, wheels...
Usually if we're using microcontroller in the system, we'll tune the PWM given by microcontroller to L293D motor driver. It means each motor will get different PWM value so that as a result, both can rotate at almost same speed. Then the RC car can go straight.

[picpicpikapika]

Hi,
Thanks a lot...
Can I connect a capacitor across my dc motor??? Why type of capacitor can I use??

[A380]

Normally we place a ceramic capacitor 0.1uF (104) parallel to motor terminals.

[picpicpikapika]

Hi all the experts here,

I have finished my project and the project presentation was quite successful...
Thank you very much for all the assistance and suggestions...
Thanks a lot.

[sich]

Well done! We're glad that you find this forum helpful!