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Arduino tamiya twin motor gear power supply and stuff

 

Hello thereI am building a simple Arduino tank but the problem is that after running it for 20? seconds it starts to run slower and slower. Then after turning it off, and on it does not run anymore. After letting it stay off for almost 5 minutes, it runs really slow. Looks like the 9v battery can't handle it?

So let's explain what I have:

Arduino UNO, breadboard, . The Arduino is using the USB connection to power up, The two DC motors use one 9V battery.

On the website where I bought the 754, I read that it gives 2A, is that for each output or both together? because each DC motor needs at least 2A. And is the sn754410ne anything good? I have seen a few using this, also can be found on youtube, running to motors.

 

 

I want to use a better battery pack, for example a LIPO battery pack, and I don't use any capacitors right now, do I need to use it if I for example  use 2x 9V battery or 2x LIPO 7,2V? The motors run each on 3V -  6V.

If you guys know anything better for powering this baby up, please tell me. I want to use the tank for atleast half hour or more?

Setup:

PINS
1 to pin 9 on Arduino board
2 to pin 3 on Arduino board
3 to motor1
4 to the gnd rail on the breadboard
5 to the gnd rail on the breadboard
6 to motor1
7 to pin 4 Arduino
8 to power (+) rail.
9 to pin 10 Arduino
10 to pin 5 Arduino
11 to motor2
12 to GND rail
13 to GND rail
14 to motor2
15 to pin 6 Arduino
16 to power (+) rail

Power (+) rail on the breadboard has 9V battery connected, gnd on the breadboard has 9V gnd, and arduino gnd connected.

 

Any other advice is also appreciated, am just a newbie at this.

 

Thanks,

 

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I have stated this a number of times to a number of different people trying to run their 'bot on a 9v battery. On average, I believe, a 9v can supply about 800 mAh of power(?)/current(?). A set of rechargeable AA batteries can offer 2 to 3 times that at the cost of extra weight. Check wikipedia for 9v vs AA or even some of the better AAA batteries. Either add a battery pack for your motors, or, switch completely to a AA battery pack for your bot.

There are some/many here that would suggest you even consider LiPos, but, without the proper charger, that might not be the best option.

Yeah, I know.  But folks WILL keep doing it.  It's a natural assumption for anyone who doesn't understand the finer points of battery capacity and current draw.  The microcontroller needs 5 volts and often has some sort of voltage regulator, they might even have a 9v battery clip that came with their "Arduino beginners kit."  So they use it, and it works--For a few minutes.

Thank you for your reply! I'll try some AAA recharchables and in the future some LiPos with proper charger. Sorry if my question was a little bit stupid. 

A 9v battery is NOT suitable as a power supply for motors.  You could run the Arduino off it for a while, but motors will suck it dry in minutes.

Your motor driver has a peak current of 2 amps and a constant current of 1 amp.  It's probably a little light for a Tamiya dual motor.  Some folks have piggybacked motor drivers to double their current output.  You could try that if your motor driver gets too hot.

.

Thank you for your reply, 

I have a spare 754 here, would that help? Using 2 754's each running one DC motor.

 

EDIT* 

So two 754's on each other would do the trick?

Piggybacked means you stack the driver chips one on top of the other, with the top ones legs pinched in a bit so that it grasps onto the bottom one, taking care that they have the same alignment.  Then CAREFULLY solder each set of pins together, again taking care to not create bridges across adjacent pins.

You do this at your own risk.  If you're new to soldering, it's not exactly a beginners project. And while I've seen it work with some driver IC's, it might not work with all.  I don't recall seeing it done with that particular circuit, but I don't see any reason why it shouldn't.

I used to do repairs on video teletypes that had a preprogrammed 8051 in them.  The replacement part cost almost $100, and the $3 spares we had in the store wouldn't work till they were programmed;  and of course I didn't have a programmer that would work on an 8051.  SO, I found out I could piggyback a new one over an old one, go to the setup screen and enter the customer's configuration, then turn off the terminal and swap the chips.  I learned that trick after we had charged one customer on numerous occasions for replacing the $100 part.  I wonder what my boss charged them for the ones repaired with my cost cutting shortcut.

Never mind.  I tend to ramble.

Well awesome to know, thank you!

Well the configuration now is:

2x754's stacked (It works, get's a little warm but nothing much)

Arduino

2 push buttons (left motor/right motor)

twin gear.

 

Everything is powered off the 5V of the Arduino UNO R3. So no external power source. 

 

Let me say: 'It works!', but the question is, will this harm the Arduino? Everything running on the 5V for now?