Show Posts
Pages: 1 ... 390 391 [392] 393 394 ... 830
5866  Using Arduino / General Electronics / Re: problem with schematic on: May 17, 2013, 05:04:09 pm
Use a multimeter to see the voltages, all the symptoms suggest battery backwards.
5867  Using Arduino / General Electronics / Re: powering with a 11v lipo battery on: May 17, 2013, 05:03:11 pm
You should consider adding a fuse to the LiPo supply since those batteries can supply huge currents
if there is a short - the fuse prevents the wiring from melting / catching fire.  Add an inline fuse to the
+ve supply close to the battery.
5868  Using Arduino / General Electronics / Re: USB D+/D- Resistors on: May 17, 2013, 05:00:22 pm
Sounds plausible, but they should be more like 47 ohm if they are the terminators.
5869  Using Arduino / General Electronics / Re: My serious fail with ribbon cable on: May 17, 2013, 04:57:59 pm
Why not ask wikipedia?
5870  Using Arduino / Programming Questions / Re: delay() & equivalent not working. on: May 17, 2013, 04:53:19 pm
You need to post the entire sketch so we can work out what's happening.
5871  Using Arduino / Programming Questions / Re: Splitting Long into Bytes & recombining on: May 17, 2013, 04:51:25 pm
You are victim of casting to the default type, namely int (signed).
In this line the sub-expressions like "byte1 << 24" are cast to the default int type,
which is signed 16 bit.
  recomb = byte1 << 24 | byte2 << 16 | byte3 << 8 | byte4;

How about using something like this:
  recomb = byte1 ;
  recomb = (recomb << 8) | byte2 ;
  recomb = (recomb << 8) | byte3 ;
  recomb = (recomb << 8) | byte4 ;
in which all the intermediate expressions are unsigned.  (Caveat, I haven't tested this)
5872  Using Arduino / General Electronics / Re: SPI clock frequency when using ADC on: May 16, 2013, 08:16:36 pm
Thanks.  I'm really just trying to figure out if it is possible to damage the IC by overclocking.  Seems unlikely.  The reason I might want to "take the chance" is that I can't accomplish my goals by limiting myself to 1MHz clock.  I need more speed, and that's why I'd like to go faster, at the possible expense of some accuracy.

Its not running at any significant power level so over clocking won't risk burning it out.
5873  Using Arduino / General Electronics / Re: problem with schematic on: May 16, 2013, 08:10:00 pm
You connected the battery backwards, it overheated...
5874  Using Arduino / General Electronics / Re: Duty cycle of Arduino on: May 16, 2013, 08:05:35 pm
The only issue is heat dissipation (if in a confined space) - and your electricity bill!

If your sketch writes to EEPROM then the limited write-cycles of that would be the limiting factor.
Also the data retention time for the FLASH memory might be an issue after many years - quoting
from the datasheet:
Reliability Qualification results show that the projected data retention failure rate is much less
than 1 PPM over 20 years at 85°C or 100 years at 25°C.
5875  Using Arduino / Programming Questions / Re: Newbie here!! Starting a loop while its still finishing? on: May 16, 2013, 07:55:49 pm
Usually you drive 2 phases at a time, the other being open-circuit.  That does require 6 pins to
control all 6 MOSFETs of the 3-phase bridge.  Its called trapezoidal drive.
5876  Using Arduino / Programming Questions / Re: Problem when changing pwm duty cycle Timer2 on: May 16, 2013, 07:39:56 pm
2A is pin 11, 2B is pin 3.

Which mode are you trying to use - you don't explicitly set all the WGM bits, so I can't tell if its mode 3 or 7.
5877  Using Arduino / Motors, Mechanics, and Power / Re: Continuous Servo/Relay issue on: May 16, 2013, 03:08:02 pm
You mustn't turn off power to the servo while it is still being sent PWM signals, you risk damaging it or the Arduino.

First detach() the servo from that pin, then digitalWrite (servoPin, LOW), then turn off the power to the servo.
5878  Using Arduino / Programming Questions / Re: error: unknown escape sequence '\c' problem on: May 16, 2013, 03:04:35 pm
Why are you looking for 0x12 at all? The usual terminating characters are 0x10 and 0x13.

newline/linefeed = 10  (decimal, not hex),
carriage-return  = 13
5879  Using Arduino / Programming Questions / Re: Reading encoder gives very strange results using the encoder library on: May 16, 2013, 03:01:30 pm
Rather than start a flame war I'll address the question.

The large numbers are at or near 2^30-2^16 which is suggestive.  Without seeing the code
for update() its hard to see why this should be.  The 2^16 error would be indicative of the
noInterrupts() failing perhaps, but the 2^30 error is strange, but from the log its clearly
coming from the read() function, which calls update().

Are all the necessary volatile declarations present?
5880  Using Arduino / General Electronics / Re: Using a single power source for Arduino and stepper on: May 16, 2013, 08:13:28 am
Just be sure to check the spec for any regulator chip - not all of them go to 27V (although
7805's etc do, I believe).  A cheap LM2596 switch-mode DC-DC converter from eBay perhaps?
Pages: 1 ... 390 391 [392] 393 394 ... 830