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211  Forum 2005-2010 (read only) / Troubleshooting / Re: Fried Duemilanove... on: May 09, 2010, 03:10:37 pm
A new chip should fix it; you need one with the boot-loader, of course. You should remove the existing chip and check the supply voltage at the socket, to make sure that the regulator hasn't failed.
212  Forum 2005-2010 (read only) / Troubleshooting / Re: FTDI chip dead? on: April 21, 2010, 02:02:28 pm
If you are handy with a soldering iron you could replace it. Chip Quik is very good stuff for removing chips without damaging the board:

http://www.chipquikinc.com/
213  Forum 2005-2010 (read only) / Troubleshooting / Re: Supplying power to Arduino with transformer? on: April 21, 2010, 02:09:21 pm
1000 uF or 2,200 uF should be plenty. Get a 16V one.

Use a regulator like an LM317 to get your 9V, resistors won't work properly.
214  Forum 2005-2010 (read only) / Development / Re: Duemilanove engineering drawings on: August 06, 2010, 03:37:28 pm
Here is my version:



I imported the Eagle file into Pulsonix, and used that for the dimensioning.
215  Forum 2005-2010 (read only) / Development / Re: Best place to fabricate custom Arduino PCB? on: August 10, 2010, 08:37:52 am
I use PCB Pool a lot.
216  Forum 2005-2010 (read only) / Interfacing / Re: TTL to LVTTL on: May 06, 2010, 02:47:15 pm
I've seen MOSFETs used for level conversion, I suppose that is the same sort of idea. I've ordered some for myself, as well. They might come in useful.
217  Forum 2005-2010 (read only) / Interfacing / Re: TTL to LVTTL on: May 06, 2010, 09:33:08 am
What GPS is it?

What is the Farnell order code? I'm just about to place an order with Farnell UK and I could add it, then post it on. I don't pay for shipping.
218  Forum 2005-2010 (read only) / Interfacing / Re: What capacitor for stabilising AC? on: January 12, 2011, 06:57:10 am
Use a full-wave (bridge) rectifier and you can use a smaller capacitor. The value depends on the current; as that will be minimal, something like 470 uF should be OK. You will also need to clamp the voltage to <5V, to avoid damaging the Arduino input. You could use a diode to the 5V supply with a resistor.
219  Forum 2005-2010 (read only) / Interfacing / Re: Mega + GE 863 Quad, Serial data corrupt on: August 11, 2010, 05:38:20 pm
FWIW, I didn't have any problems interfacing the GE863 to a small PIC, using assembly language. I used 38,400 baud and didn't need any delays apart from the ones in the manual.
220  Forum 2005-2010 (read only) / Interfacing / Re: max milliamps on: January 12, 2011, 06:52:40 am
You should be using a current-limiting resistor in the base connections.

The AVR outputs can deliver a max. current of 40 mA each, with a total current of 200 mA (IIRC). I'd aim for no more than 10 mA on each one.

The current available from the USB supply is negotiated in the software, 500 mA is the default value, and that is probably what is available to the Arduino. You need to calculate the total current consumption of your circuit, and use an external supply if it is excessive.
221  Forum 2005-2010 (read only) / Interfacing / Re: Galvanic Vestibular Stimulation - AWESOME! on: August 26, 2010, 11:50:34 pm
Attaching anything connected to a mains supply to yourself like that can be *very* dangerous. Use a battery to power the Arduino.
222  Forum 2005-2010 (read only) / Interfacing / Re: Talk between Arduino and PC wirelessly? Questions. on: December 12, 2010, 10:31:50 pm
Here is a PIC program of mine which checks the SPI comms between the MCU and the Nordic chip:

Code:
/*
** test.c
** SPI test program for PIC18F4520 and nRF24L01 or nRF24L01+
** Checks SPI comms between PIC and wireless chip
**
** RA0      LED (output)
** RA1      PB (input)
*/

#include <p18f4520.h>
#include <spi.h>

//function prototypes
unsigned char spi_Send_Read(unsigned char);
void dly(void);

// Defines
#define SPI_SCK            LATCbits.LATC3            // Clock pin, PORTC pin 3
#define SPI_SO            LATCbits.LATC5            // Serial output pin, PORTC pin 5
#define SPI_SI            PORTCbits.RC4            // Serial input pin, PORTC pin 4
#define SPI_CSN            LATCbits.LATC2            // CSN output pin, PORTC pin 2
#define SPI_CE            LATCbits.LATC1            // CE output pin, PORTC pin 1
#define SPI_IRQ            PORTBbits.RB0            // IRQ input pin, PORTB pin 0
#define SPI_SCALE      4                          // postscaling of signal
#define LED                  LATAbits.LATA0
#define PB                  PORTAbits.RA1


// Macros
#define nop() _asm nop _endasm

void main(void)
{
      unsigned char status = 0;
      unsigned char data[5];
      int i;

      // run internal oscillator at 8 MHz
      OSCCON = OSCCON | 0b01110000;
      while (!OSCCONbits.IOFS)      // wait for IOFS to go high
            ;

      OpenSPI(SPI_FOSC_16, MODE_00, SMPMID); //open SPI1
      PORTA = 0x00;
      ADCON1 = 0x0F;            // set up PORTA to be digital I/Os
      TRISA = 0x02;            // PORTA<7.2,0> outputs PORTA<1> input
      TRISCbits.TRISC3 = 0;      // SDO output
      TRISCbits.TRISC5 = 0;   // SCK output
      TRISCbits.TRISC2 = 0;      // CSN output
      TRISCbits.TRISC1 = 0;      // CE output
      SPI_CSN = 1;            // CSN high
      SPI_SCK = 0;            // SCK low
      SPI_CE      = 0;            // CE low
      nop();

      //write TX_ADDRESS register
      SPI_CSN = 0;                  //CSN low
      spi_Send_Read(0x30);
      spi_Send_Read(0x11);
      spi_Send_Read(0x22);
      spi_Send_Read(0x33);
      spi_Send_Read(0x44);
      spi_Send_Read(0x55);
      SPI_CSN = 1;                  //CSN high


      //read TX_ADDRESS register
      //Check that values are correct using the MPLAB debugger
      SPI_CSN = 0;                  //CSN low
      status = spi_Send_Read(0x10);
      data[0] = spi_Send_Read(0x00);      // 0x11
      data[1] = spi_Send_Read(0x00);      // 0x22
      data[2] = spi_Send_Read(0x00);      // 0x33
      data[3] = spi_Send_Read(0x00);      // 0x44
      data[4] = spi_Send_Read(0x00);      // 0x55
      SPI_CSN = 1;                              // CSN high

      while (1)
            ;
}


unsigned char spi_Send_Read(unsigned char byte)
{
      SSPBUF = byte;      
      while(!DataRdySPI())
            ;      
      return SSPBUF;
}

It uses the Microchip SPI library.

The code should work on the Arduino with a few changes. You don't have a debugger so you will have to send the results back to the PC via the serial monitor.
223  Forum 2005-2010 (read only) / Interfacing / Re: +-10V Analog input on: October 17, 2010, 05:29:33 am
This is the standard circuit for that problem:



It converts +-5V to 0 to +5V.

Use larger resistors, that SPICE simulation was to prove to someone that it worked.
224  Forum 2005-2010 (read only) / Interfacing / Re: Arduino WIRELESS Communication on: October 15, 2010, 01:02:14 pm
Range?
225  Forum 2005-2010 (read only) / Interfacing / Re: The forbidden Arduino! on: August 24, 2010, 01:45:24 pm
It's got a USB interface on the chip, and there are no availability problems?
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