Can I connect Arduino to 9 V battery ( I mean 4xAA - rechardable + 2xAA - normal = 7,8 ) and then VIN pin connect to H-bridge ( I have L293D , which will operate with 2 motors ) Is it possibility ? For better understand I make a picture. Should I use other supply for arduino ? In these "project" I will use even next items. Thanks in advance .
The motors need a separate power supply that matches their specifications.
a) power supply for the 'logic' (arduino, H-bridge, ...)
b) power supply for the load (motors, high power leds, ...)
If you don't run the motor at full speed then you can get away with using a higher voltage than the motor is rated at.
PWM-ing the enable pin of the H-bridge is an option, but you had better make sure that never ever fails.
but you had better make sure that never ever fails.
Well if it does fail it is not instant smoke, the motor just runs fast and hot. Disconnect it as soon as you see this and it will be fine. Motors can stand quite a bit of overload before they melt.
Do you mean that I have to use 6xAA for arduino and 2x(2xAA) for two motors . It seems to me a lot . Should I use 10xAA batteries ? I think that Arduino has enough power from 6 batteries even for motors . Do you have any other idea ? What about connect arduino to small 9V battery and then 4 batteries for each motors . Thank you in advance .
Do you mean that I have to use 6xAA for arduino and 2x(2xAA) for two motors .
I didn't suggest it and operating a L293D with a motor voltage lower than the supply voltage is something the data sheet for the device says you shouldn't do.
Operating a motor on a different supply to the arduino does make sense because sometimes the motor generates enough interference to reset the arduino.
What about connect arduino to small 9V battery
These batteries are rubbish when it comes to drawing power from them and are best avoided.
Top and bottom is that a L293D is not very suitable for driving small voltage motors.
Have a look at this page:-
http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
But if L293D is possibly for motors I dont want to change it ( Could it destroy or damage motors ? ) I am interested in supply voltage more. What are you suggest? I would like rather to cheap version , if it is possible.
Do you mean that I would connect motor direct to arduino ? But I want to rotate to forward and backward.
EDIT : Can I connect 5xAA bateries to Arduino and parallel to chip ( L293D - power for motors , maybe it would be enough for 3V motors 
) ?
Five batteries are suitable for me .
Do you mean that I would connect motor direct to arduino ?
No.
I am interested in supply voltage more
If you supply more voltage to your motor it will run hotter and if you run it for too long with this higher voltage then the motor will burn out.
You have to supply more than 3V to the L293 chip. 5 volts is fine to supply it with. However if you do then you could burn the motor out if you ran it for too long at full power. Using PWM to run it at 3/4 power would be the best thing to do.
You can try and run it off the same 5V as the motor but it might create too much interference. In which case you have to either:-
Grumpy_Mike:
2) Add supply decoupling so the interference does not cause your arduino problems like random resting. A page about decoupling is here:-
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html
I check the page ( and I remember that I learned it in school ) but I don't know how can I use this in my issue. I should connect arduino and chip parallel and I give there some capacitors ?
I should connect arduino and chip parallel and I give there some capacitors ?
It all depends on your motors as to what you need.
The best way is to connect the motor to the positive supply through an inductor with a capacitor to ground on each side of the inductor.
Grumpy_Mike:
I should connect arduino and chip parallel and I give there some capacitors ?
It all depends on your motors as to what you need.
The best way is to connect the motor to the positive supply through an inductor with a capacitor to ground on each side of the inductor.
But inductor in direct current behaves like resistance , nothing more ( I read it on Wikipedia ) , then what's the meaning of using inductor ?
Yes but the point is that the interference signal is not DC it is AC. So the inductor impeded the interference while letting the DC current get through.
But inductor in direct current behaves like resistance
Not quite, a pure inductor acts like a short circuit to DC. The only resistance comes from the wire it takes to wind it. This is very small in the values of inductors we are talking about here.
I'm sorry for my nescience but I still dont understand what I would connect together and what not . If you have a little time ,can you make a picture of involvement ? One picture is better than thousand word . Thanks in anvace .
It was on the link I gave you to read:-
hi, I have a quick question that is related to this thread: does anyone know if I can pwm the enable pin on the L293D to control the speed of the dc motor? So that I can control both the speed and direction of the dc motor using the L293D. My small dc motor runs on about 5V.
if I can pwm the enable pin on the L293D to control the speed of the dc motor?
Yes you can.
A few questions ?
)
To much questions ( You are smart , but I am noob ) I'd rather use 10xAA bateries , this is to hard for me .
No the arduino is connected to the motor in what ever way you want to control it. You were asking about a H-bridge and I was telling you about how to power the motor and the arduino from the same supply. The diagram is showing how to power the motor and not let the interference get onto the power supply and so feed into the arduino and upset it.
The other component you circled is a capacitor, it is an electrolytic capacitor, the other one is a non polarised one, preferable a ceramic one.
So connection replaced chip L293 ( if I understand you ) and can I use it for two motors ? But how can arduino control this motor (Should I insert any component which disturb connection if I want to stop motor ? ) and next question : Should I use resistance in this connection if arduino needs more than 7V but for the motors are 7V limit ?
