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Topic: Use digital pins to use a 8-9V Motor ? (Read 1 time) previous topic - next topic

yeko

Nov 21, 2013, 07:04 pm Last Edit: Nov 21, 2013, 07:08 pm by yeko Reason: 1
Hi guys,

I'm making a DIY IR Controlled Car . So for that I've 2 x 8-9V motor .
You understand now what's my problem : digitals pins of arduino nano (or uno, i have both) give just 5 V but I need 8-9 V.
I must use digital pins because i follow this tutorial :
http://www.instructables.com/id/Simple-2-way-motor-control-for-the-arduino/#intro

Thanks guys in advance !

(sorry for my bad english)

JimboZA

We shouldn't even think of plugging a motor in like that, even if it works on 5v. At a minimum you should control it with a transistor (with a diode across the motor). That won't allow reversal of direction though, so you'll need an h-bridge.

Have a look at small, cheap, controller boards like the Pololu 2130
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

jremington

Just another of those awful, completely misleading tutorials! Note the disclaimer:
Quote

I am not responsible for any thing bad that happens to you or to your arduino!
(damage to the Arduino is quite likely with 99.99% of motors chosen at random)

MarkT

That instructable might teach you why you don't driver motors from logic devices
the hard way - steer well clear of it.  All inductive loads can destroy chips if you don't
make sure you have the right protection circuitry (free-wheel diode, snubber circuit,
etc).

The Arduino cannot supply enough current for all but the most microscopic of motors
without exceeding its abs-max ratings - don't do this!
[ I won't respond to messages, use the forum please ]

yeko

Ok thank guys for your answers !
I would use a L293D or the DRV8833 , there is a lot of tuts on google about it .

So thanks for help !
Bye

JimboZA

Seeing as you have the ability to choose, rather stay away from the 293 and it's larger cousin the 298: they are older technology and wasteful of energy. Go with newer stuff like the 8833 like that Pololu I linked.

Have fun....
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

yeko

I think to the Pololu but I don't found a tuto to use it .

JimboZA

You don't really need a tutorial- look at the "minimal wiring diagram" in the Pictures tab....

You supply the motor power across Vin and Gnd as the pic shows: the control is provided by the AIN1/2 and BIN1/2 lines on the left,  the outputs AOUT1/2 and BOUT1/2 to do what you need to drive the motors.

There are 2 motor channels, A and B. Each has 2 inputs, which are digital lines from your Arduino. If you want speed control, at least one of those will need to be a PWM line. You control direction by changing polarity on those 2 inputs. So if say BIN1 high and BIN2 low is clockwise, the BIN1 low and BIN2 high will be anti-clockwise. Pulse either with PWM and you'll get speed control.

Don't forget to join the grounds together.



"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

yeko

#8
Nov 23, 2013, 10:32 am Last Edit: Nov 23, 2013, 08:18 pm by yeko Reason: 1
Ok the minimal wiring schema isn't hard to understand ! So thanks for that .

But i want to find it on ebay or amazon or another site with low shipping cost because i live in France and i don't want to pay 15$ of shipping fee for a 5$ product (DRV8833) .  :)

Instead of the L932D on ebay (because it's older)



yeko

So finally i buy a SN754410 on ebay (http://goo.gl/mUuPoV) .

There is a mini-list of Double H-Bridge IC :
- DRV8833
- SN754410
- L293
- L298

Thanks to all !

Bstanko6

I use a sainsmart l293d motor shield. I find it to work quite well, though you need to refer to adafruit for tutorial as there is none under 'sainsmart'.

JimboZA

The 293 and 298 are wasteful of energy remember. The SN754410  is pin-compatible with the 293, but I'm not sure if it's the same technology?
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

yeko

For the L293 and L298 you need 2 Capacitors on pins 4,5 and 13,12 compared to the SN754410 that doesn't need it .
That's why there are shields for L293 and L298 with integrated capacitor . It's simply to use .

But how to you know they are wasteful of energy ?

JimboZA

Because there's always a significant voltage drop across those things. I forget what it is for 293 but the 298 loses 1.8 min, up to something like 4 at higher current. Since that voltage is at a current, that's power, and power times time is energy. Look at pics of a 298 shield and you'll see a heatsink the size of a truck. The 293's middle 4 ground pins are also for attachment to heatsink.

The 8833 may need a heatsink at high current but it's not in the same league.
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

yeko

#14
Nov 24, 2013, 08:07 pm Last Edit: Nov 24, 2013, 08:12 pm by yeko Reason: 1
I've seen the sainsmart shield but it is compatible with arduino uno (duemilanove and mega) and i've a arduino nano .

JimboZA , can you talk me about the SN754410 ?  (wasteful ?)

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