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1  Using Arduino / Project Guidance / Re: can i use Arduino micro-controller to copy files from SD card to External HD ?? on: April 09, 2014, 05:29:32 am
You will have better luck using raspberry pi
2  Using Arduino / General Electronics / Re: Battery charger on: April 07, 2014, 10:13:53 pm
No,

 IBat = VProg/RProg X 1200 (VPROG=1V)

750mA = 0.75A

0.75 = (1) * 1200 / R
R = 1200/0.75
R = 1600 Ohms
R = 1.6K Ohms

So you have use 1.6K ohms resistor for RProg.
3  Using Arduino / General Electronics / Re: Measuring Voltage of Battery on: April 05, 2014, 10:25:56 pm
Read this
http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/
4  Using Arduino / General Electronics / Re: Battery charger on: April 04, 2014, 06:12:42 pm
Yes, reference to the datasheet you can calculate the resistor base this formula  IBat = VProg/RProg X 1200 (VPROG=1V)



Thank you guys!

Quote
240mhA battery, your charge current change to 130mA
So this means that i always have to choose the lower value when i don't have the right value?

Also, can i charge this battery with that charger:
http://www.ebay.com/itm/BLC-2-Battery-for-Nokia-3310-3330-3510I-3320-5510-6800-6810-6650-3410-/360788753110?pt=LH_DefaultDomain_3&hash=item5400af7ad6
This is a 3.6V battery with 750mA
yes
5  Using Arduino / General Electronics / Re: Battery charger on: April 04, 2014, 09:19:52 am
Yes it can, but you have to set to correct charging current.
How?
Look at the Charge Table on the page, you have to change the value of the resistor Rprog
Since you are using 240mhA battery, your charge current change to 130mA so you have to change Rprog to 10K ohms
The resistor need to change was circle in RED
6  Using Arduino / General Electronics / Re: Battery charger on: April 04, 2014, 07:35:35 am
Yes it can, but you have to set to correct charging current.
7  Using Arduino / Project Guidance / Re: How to run a micro without USB? on: April 03, 2014, 07:56:25 am
This may be a really stupid question - What make you think that the Arduino Micro had two native serial port?
8  Using Arduino / Project Guidance / Re: plx daq and lcd keypad on: March 31, 2014, 10:45:36 am
Read this from Robin2 work on Demonstration code for several things at the same time, to replace your delay(30000) in the program
http://forum.arduino.cc/index.php?topic=223286.0
9  Using Arduino / Project Guidance / Re: How to make a waveform generator with frequency of 20hz-20Mhz on: March 31, 2014, 09:14:21 am
0-40Mhz, Sine wave generator for $25 using the AD9850 which is a Direct Digital Synthesis sine wave generator able to control by Arduino Uno.
10  Using Arduino / Project Guidance / Re: Powering LCD on: March 27, 2014, 10:29:02 am
Yes, you can Install power supply on ground level near LCD to power +5v and GND, but you have to connect the arduino GND with this GND too.

Another way was using ShiftRegister connection to your LCD, that will use only 4 wires.


https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/schematics#!shiftregister-connection
11  Using Arduino / General Electronics / Re: squeezing every bit of juice from AA batteries on: March 24, 2014, 08:00:10 am
I'd also recommend pololu.

I'd be interested to know the chips they use, but it seems they're not on the open source bandwagon.

Hi Jack,
The Step-up Voltage Regulators U1V11F3, U1V11F5, and U1V11A using TI TPS61200DRC for Adjustable version (BRR) and TPS61202DRC
 for 5V version (BRT)
http://www.ti.com/lit/ds/symlink/tps61200.pdf
12  Using Arduino / Project Guidance / Re: Reference EBooks on Arduino Programming? on: March 21, 2014, 08:02:32 am
http://playground.arduino.cc/uploads/Main/arduino_notebook_v1-1.pdf

http://www.me.umn.edu/courses/me2011/arduino/arduinoGuide.pdf
13  Using Arduino / Project Guidance / Re: LCD with SPI = saving pins? on: March 20, 2014, 06:12:55 am
You can expand more input/output with some logic IC

How to use TLC5940s to add more PWM outputs.

This PCF8574 chip (datasheet) implements I2C in slave mode and offers 8 independent input/output pins.
http://playground.arduino.cc/Main/PCF8574Class

Serial to Parallel using 74HC595 Shift Register http://www.arduino.cc/en/Tutorial/ShiftOut for more output pin
Arduino I2C Expansion I/O using PCA9535 & PCA9555
14  Using Arduino / Project Guidance / Re: connection of dtmf decoder and arduino uno on: March 19, 2014, 06:30:44 am
But I saw this code using pin 16,17,18,&19, it say can be connected to any four digital pins.


Code:
const int StD=0;           // Can be connected to Interrupt 0/1 (i.e. D2/D3)
const int Q[4]={
  16,17,18,19};            // Can be connected to any four digital pins
int key;

void setup()
{
  Serial.begin(9600);
  attachInterrupt(StD,dtmf,RISING);  // attach the interrupt to be activated at the Rising edge of the StD pulse
  for(int i=0;i<4;i++)
    pinMode(Q[i],INPUT);             // define the data pins Q1-Q4 as input pins
}

void loop()
{
}

void dtmf()
{
  key=0;
  for(int i=0;i<4;i++)
    key+=digitalRead(Q[i])<<i;        // Read the data pins digitally and convert it into a decimal number
  Serial.println(key);
}
15  Using Arduino / Project Guidance / Re: Problem making LED dot matrix work on: March 17, 2014, 08:43:17 am
Here is the way to make  your sure electronics RED GREEN Bicolour 16x32 Led matrix work
http://playground.arduino.cc/Main/HT1632C#.Uyb8vz-SzMw
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