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6541  Using Arduino / Audio / Re: help w/ pocket piano on: January 09, 2012, 11:19:13 pm
The caps from Vcc to Ground are 'bypass' capacitors and are generally kept as close as possible to the power pins of the nearby chips.

I think you are correct that "POT_1" is a typo and they should connect to Ground.
6542  Using Arduino / Sensors / Re: Voltage Reference OK on AREF? on: January 09, 2012, 11:14:19 pm
I think the ATmega comes up with the ARef line connected to the Vcc line.  This might cause problems with the other users of the analog reference voltage until you get a chance to switch the ARef to External.  I think they recommend having the ARef voltage supplied thorough a resistor so while it is shorted to Vcc it doesn't draw a lot of current.
6543  Topics / Robotics / Re: Controlling 2 linear actuators with dual h bridge on: January 09, 2012, 05:30:12 pm

"Input voltage is 12VDC and recommended fuse is 10 Amp."

That should mean that if your H-bridge can source 10 amps you will be OK.  I would guess the expected stall current would be somewhat less than that.  Note that these are rated for 20% duty cycle (only moving 20% of the time).
6544  Using Arduino / LEDs and Multiplexing / Re: help with parameters on: January 09, 2012, 04:18:08 pm
Because you have your LED between the output pin and +5 it will be OFF when the pin is HIGH (both pins are at +5 so no current flows) and ON when the pin is LOW (the anode is at +5 and the cathode is at Ground so current flows).  You can't connect the common anode to Ground so you will have to invert the logic to the three outputs.

If you had a Common Cathode RGB LED you would connect the Cathode to Ground and the Anodes to output pins.

Also put in current limiting resistors for each LED.
6545  Using Arduino / Installation & Troubleshooting / Re: Fried certain component on arduino uno on: January 09, 2012, 04:08:06 pm
Is it the big chip just above the power jack with one large lead on the left and three smaller leads on the right?  That would be the 5V voltage regulator.  Not too hard to replace.
6546  Development / Suggestions for the Arduino Project / Re: pulseIn Bug on: January 09, 2012, 04:01:27 pm
There is no obvious cause for a 40-50 microsecond delay.  It doesn't look like the code has been touched since 2007.  Perhaps something in your code between calls to pulseIn() is introducing  a delay.

#include "wiring_private.h"
#include "pins_arduino.h"

/* Measures the length (in microseconds) of a pulse on the pin; state is HIGH
 * or LOW, the type of pulse to measure.  Works on pulses from 2-3 microseconds
 * to 3 minutes in length, but must be called at least a few dozen microseconds
 * before the start of the pulse. */
unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
// cache the port and bit of the pin in order to speed up the
// pulse width measuring loop and achieve finer resolution.  calling
// digitalRead() instead yields much coarser resolution.
uint8_t bit = digitalPinToBitMask(pin);
uint8_t port = digitalPinToPort(pin);
uint8_t stateMask = (state ? bit : 0);
unsigned long width = 0; // keep initialization out of time critical area

// convert the timeout from microseconds to a number of times through
// the initial loop; it takes 16 clock cycles per iteration.
unsigned long numloops = 0;
unsigned long maxloops = microsecondsToClockCycles(timeout) / 16;

// wait for any previous pulse to end
while ((*portInputRegister(port) & bit) == stateMask)
if (numloops++ == maxloops)
return 0;

// wait for the pulse to start
while ((*portInputRegister(port) & bit) != stateMask)
if (numloops++ == maxloops)
return 0;

// wait for the pulse to stop
while ((*portInputRegister(port) & bit) == stateMask) {
if (numloops++ == maxloops)
return 0;

// convert the reading to microseconds. The loop has been determined
// to be 20 clock cycles long and have about 16 clocks between the edge
// and the start of the loop. There will be some error introduced by
// the interrupt handlers.
return clockCyclesToMicroseconds(width * 21 + 16);
6547  Using Arduino / Audio / Re: can't get basic midi sketch to work on: January 09, 2012, 12:55:55 pm
For the output are you using Serial.write(value) or Serial.print(value, BYTE)?  Are you using Arduino 0.23 or Arduino 1.0?
6548  Using Arduino / Storage / Re: EEPROM Chip resets when arduino is reset on: January 09, 2012, 12:50:35 pm
You are attempting to read data from the buffer (result = Wire.receive()smiley-wink before you check to see if there is any data in the buffer (Wire.available()).  Perhaps the library is returning an error due to a buffer under-run.  It is possible that your data is in the EEPROM but your reading code is incorrect.
6549  Using Arduino / General Electronics / Re: What value resistor? on: January 09, 2012, 11:12:19 am
I hate it when the package fails to provide vital information.  Fortunately, 20 mA is a fairly common value for indicator LED's.

Try (Voltage - 3) / 0.020 = Ohms.

For example, with a 5V supply it would be 2V/0.02A = 400 ohms. 

Not sure what the "PLUS 100 OHMS" is about.
6550  Using Arduino / Audio / Re: can't get basic midi sketch to work on: January 09, 2012, 11:03:21 am
The electrical specifications for the MIDI connector ( shows a second 220 Ohm resistor from the TX pin to Pin 5 of the MIDI connector.  Couldn't hurt to try that.

It might also help to connect the MIDI Ground pin (pin 2) to the shell of the MIDI connector.
6551  Using Arduino / Audio / Re: can't get basic midi sketch to work on: January 09, 2012, 10:50:06 am
Could the 220 ohm (Red Red Brown) resistor be faulty?  Do you have a meter you could check it with?
6552  Using Arduino / Sensors / Re: Can I get a sensor shield to work with this sensor on: January 09, 2012, 10:23:31 am
The information you provided is not specific enough.  You should provide a pointer to the full specification of the transducer or at least provide the manufacturer's model number.
6553  Using Arduino / Audio / Re: can't get basic midi sketch to work on: January 09, 2012, 10:16:15 am
Does your MIDI-OX installation work with other MIDI devices such as a keyboard?

Have you tried hooking the Arduino to the input of a MIDI instrument to see if anything plays?
6554  Using Arduino / Project Guidance / Re: Run standalone? on: January 09, 2012, 08:27:29 am
Quick question, I'm a newbie. After programing a Arduino with the computer can it be flashed to run on it's own?

Yes,  Your sketch is uploaded into FLASH memory.  Apply power to the Arduino and your sketch will start running.
6555  Using Arduino / Motors, Mechanics, and Power / Re: Servo SM-S3317S SpringRC on: January 08, 2012, 10:23:58 am
My guess is that the servo is drawing too much power and causing the Arduino to reset.  Try running the servo off a separate power supply, like four AA batteries in series.  Connect battery + to the red wire of the servo and battery - to the black wire.  Then connect Arduino ground ALSO to the black wire and the signal pin to the white wire.
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