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1  Using Arduino / LEDs and Multiplexing / Problem with Wrobot 16x16 led matrix on: April 16, 2011, 01:33:34 pm
Hi all,
i bought from web one of this matrix: http://tinyurl.com/3zjhuk7

I followed all instructions and i connected it to my arduino uno without sensor shield (it's necessary?).

I've used IN pins of the matrix in this way:
Quote
Arduino digital pin 4,5,6,7 to input pin OIA,OIB,OIC,OID of LED screen
Arduino digital pin 8,9,10 to pin SER,SCK,RCK of LED screen
LED screen GND to Arduino ground and VCC of LED screen to Arduino power

I've also uploaded code.

But, using the code (open link to find it) and changing only
Code:
#define ScreenNO 4
to
Code:
#define ScreenNO 1
my matrix show me only lines without characters!!




What could be the cause?
What's wrong in wires or code?

thanks all!
2  Using Arduino / Motors, Mechanics, and Power / Re: Control speed of DC Motor with potentiometer on: March 30, 2011, 01:22:20 pm
@johnwasser

Right! Now is connected to pin 3 and the speed is controlled!!

Many thanks man!
3  Using Arduino / Motors, Mechanics, and Power / Re: Control speed of DC Motor with potentiometer on: March 30, 2011, 12:43:43 pm
I get pot values.... from 0 to 1023.
Sorry for copy/paste code, analogInPin was forgotted.
What kind of value i need to pass to pot?

I'm very newbie, about coding, about electronics and about english!  smiley-lol

Quote
Maybe your speed problem would be solved if you used a PWM pin for the output.
What is a PWM pin?

Quote
You seem to have a freewheel diode in the wrong place - needs to be across the motor.
What is diode correct place? Have you a detailed example for a beginner?

thanks for helps!
4  International / Generale / Re: Perchè il potenziometro ha 3 piedini? on: March 28, 2011, 05:40:53 pm
Può darsi sia rotto, perchè attaccandone un altro a rotella funziona correttamente.

grazie
5  Using Arduino / Motors, Mechanics, and Power / Control speed of DC Motor with potentiometer on: March 28, 2011, 05:38:45 pm
hi all,
it's possible to control the speed of a dc motor with a potentiometer?
I started reading this article: http://homepage.mac.com/joester5/art/digitalart2/dcmotor.html

I've attached all successfully, but i CAN'T ABLE TO set speed!

If i turn pot, dc motor run or stop, but at the same speed (fast).



Any idea to fix this issue?

This is the used code:
Code:
int sensorValue = 0;
int outputValue = 0;
int transistorPin = 2;

void setup() {
  pinMode(transistorPin, OUTPUT);
}

void loop() {
  sensorValue = analogRead(analogInPin)/4;           
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  analogWrite(transistorPin, sensorValue);
}

tks.
6  International / Generale / Re: Perchè il potenziometro ha 3 piedini? on: March 28, 2011, 03:42:46 pm
...può darsi!
Comunque il potenziometro è connesso. Riesco a leggere i valori che però... NON CAMBIANO!!!

Anche invertendo Vcc con GND sono sempre uguali...
O sempre 0 o sempre 1023!!

Sto usando questo snippet:

  int sensorValue = analogRead(A0);
  int outputValue = map(sensorValue, 0, 1023, 0, 255); 

Il pot è conneso con p3 a Vcc, p1 a GND e p2 ad A0.

any idea?
7  International / Generale / Re: Perchè il potenziometro ha 3 piedini? on: March 28, 2011, 01:22:06 pm
Ciao,
faccio riferimento a quello in foto, in particolare la seconda foto.

Cosa intendi per contatti esterni? 3 ed 1?
La massa qual'è il 2 quindi?
Non trovo un datasheet da nessuna parte e non so come attaccarlo!
Ci vogliono delle resistenze sulla massa?

grazie.
Ah, non ho ancora un tester, quindi nulla...
8  International / Generale / Re: Perchè il potenziometro ha 3 piedini? on: March 27, 2011, 02:47:17 pm
Ciao ragazzi,
ma alla fine come si collega?
I piedini 1,2 e/o 3 dove vanno? Che resistenza ci vuole (se ci vuole)? Vcc?

Vorrei ricevere sulla seriale i cambiamenti di valore dello slider... how to?

grazie
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