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Topic: Breadboard, external power source (Read 385 times) previous topic - next topic

Stoil

Hello,

 Let's take this scheme for example:


If the arduino was plugged to a PC, which one would the motor use as a source - the arduino or the batteries ? Why ?

Regards!

Idahowalker

Neither, from that picture the chip is not powered nor is the Arduino powered.

Stoil


MarshaJ847

Looking at the data sheet for the sn75441one, pin 8 aka VCC2, is the power for the drives and should come from the batteries.
The 5v logic and enable pins are driven by the Arduino 5v when it is connected to the PC

Marsha

MorganS

How so ?
You connected the battery red wire to one of the strips on the breadboard. But there are no other wires connecting that strip to anything.

Note the black wire on the right-hand side. That connects the battery negative to the rest of your circuit.
"The problem is in the code you didn't post."

WattsThat

Quote
You connected the battery red wire to one of the strips on the breadboard. But there are no other wires connecting that strip to anything.
Incorrect. There is a yellow wire connecting battery positive to pin 8 of the 75441.

Marsha explained it in post #3.

OP: diagrams like this are why people despise fritzing crap. These are not schematics and they make the obvious obscure. They might be pretty pictures but they do not communicate well.
Vacuum tube guy in a solid state world

TomGeorge

#6
Nov 18, 2018, 06:26 am Last Edit: Nov 18, 2018, 06:26 am by TomGeorge
Hi,
Check this edited PICTURE, this why I hate fritzy.


Pin 8 IS coming from the batteries.
Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

TomGeorge

#7
Nov 18, 2018, 07:44 am Last Edit: Nov 18, 2018, 07:47 am by TomGeorge
Hi,
This will probably help, a SCHEMATIC.

Better than fritzy, it has component and pin labels. just about self-explanatory.
Also ;
  • a sense of signal flow, LEFT to RIGHT.
  • a sense of power flow TOP to BOTTOM.


Tom... :)
Everything runs on smoke, let the smoke out, it stops running....

Stoil

OK, so, IF pin8 on the driver is connected to the battery +, the power is coming from the battery. If pin8 was connected to the Arduino +, it would draw power from the arduino ? I thought pin1 and pin8 were for each side, so if you connected arduino 5v to pin1 and battery + to pin8, both would power one motor ?

Paul__B

If pin8 was connected to the Arduino +, it would draw power from the Arduino?
No, because the Arduino cannot supply power.  It would crash.

If you have a well-regulated power supply capable of sufficient current to power your motor (when stalled) and it is 5 V, then  you could use that to power the Arduino as well via the 5 V terminal.

TomGeorge

#10
Nov 18, 2018, 10:37 am Last Edit: Nov 18, 2018, 10:43 am by TomGeorge
Hi,
Look at the schematic, pin1 is the Enable pin for the other half, look at the revised fritzy, pin 1 is not connected to anything.
Pin8 is for the motor positive supply.
Pin 16 is for  the 5V to power the logic circuit in the 75441.

I think you are counting the pins the wrong way, not your fault, the fritzy doesn't tell you which is pin1.
If you look at any IC with the writing the correct way around to read, then pin1 is bottom left.



Tom.... :)
Everything runs on smoke, let the smoke out, it stops running....

Stoil

Hi,
Look at the schematic, pin1 is the Enable pin for the other half, look at the revised fritzy, pin 1 is not connected to anything.
Pin8 is for the motor positive supply.
Pin 16 is for  the 5V to power the logic circuit in the 75441.

I think you are counting the pins the wrong way, not your fault, the fritzy doesn't tell you which is pin1.
If you look at any IC with the writing the correct way around to read, then pin1 is bottom left.



Tom.... :)

This is the absolute best picture I've seen. I salute you.

TomGeorge

Hi,
Did you google    SN754410NE  datasheet

Thanks.. Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

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