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31  Using Arduino / Programming Questions / Re: Millis Accuracy Again on: April 18, 2013, 02:20:23 pm

Exactly. He's getting way too much variation to conclude that millis() are the cause.

Exactly X2

I did a quick look at your code and offer these suggestions:
1. Delay() is bad, and it appears your code is planted there. Try using a non-blocking delay.
2. You are running lots of ISRs (Serial, SPI, ADC, to identify a few) which could be blocking. Try eliminating/minimizing some and see if your timer accuracy improves.

32  Using Arduino / Programming Questions / Re: adressing data from assembler on: April 08, 2013, 12:13:47 pm
Generating your own pro/epilogue code:
33  Using Arduino / Programming Questions / Re: "RMSVal" was not declared in this slope on: April 02, 2013, 12:48:35 pm
Also check use of RMSPin v. RMSPIN
34  Using Arduino / Sensors / Re: Autonomous Lawn Mower Navigation on: March 20, 2013, 10:49:06 pm
Don't you need a surveyed point for the GPS to compare with to do differential?
35  Using Arduino / General Electronics / Re: 23K256 SRAM Issues on: February 23, 2013, 06:15:31 pm
OP, so what was your original problem?

It appears it was the HOLD pin. Thank you. Thank you. Thank you.
36  Using Arduino / General Electronics / Re: 23K256 SRAM Issues (SOLVED) on: February 23, 2013, 11:54:54 am
For anyone struggling with this, here is how I solved it:

Used the following components and wire routing:
(1) Arduino Uno
(2) Microchip 23K256
(3) SparkFun Logic Level Converter (BOB08745)
(4) 10K Resistor

Arduino--Logic Conv--23K256
GND------HV GND------VSS

Please note, no cats were harmed during the entirety of this experiment.
37  Using Arduino / General Electronics / Re: 23K256 SRAM Issues on: February 23, 2013, 01:53:49 am
I think we're on to something here. Let me release this cat and try an experiment. I'll report back...
38  Using Arduino / General Electronics / Re: 23K256 SRAM Issues on: February 22, 2013, 10:58:58 pm
I powered the chips off the arduino 3v3 pin and ran CS, SI and SCK thru a spark fun Logic Level Shifter (and also ran them thru an adafruit nxp0108 breakout board). I tired using 1k8/3k3 R voltage dividers too and with and without a pullup on CS. I get data out of the chip, but its gibberish. Thx.
39  Using Arduino / General Electronics / 23K256 SRAM Issues [solved] on: February 22, 2013, 08:12:53 pm
 I’ve spent the better part of 2 days attempting to get SPI 23K256 RAM chips to communicate with an arduino. I’ve tried 3 arduino boards (168, 328 & uno), two 23K256 chips, wired them with and without voltage dividers and logic level shifters.

I’ve tried several SPI and SPISRAM libraries found on the internet.

I’ve also read countless reports of others having similar issues and come to the conclusion these chips hate me. I view anyone claiming they've made this work skeptically.

At this point I'm contemplating sacrificing animals to the God of Peripheral Interfaces. For the sake of stray neighborhood cats, any advice would be appreciated.
40  Using Arduino / Programming Questions / Re: GPS direction/ distance problems on: February 17, 2013, 08:39:07 pm
You could be travelling backwards, looking toward your original location, but the GPS would not know this, it would display you moving toward your destination.
No, it wouldn't. It would show a vector moving away from the target. Now, it would not know, or care, which way you are facing, or whether you are moving in the direction you are facing, or not. All it knows is which way you are moving.

41  Using Arduino / Programming Questions / Re: GPS direction/ distance problems on: February 17, 2013, 10:19:36 am
Distance is in NM, so .01 = 60 feet, either GPS is not updating (indoors?) or try a destination that is closer.
42  Using Arduino / Sensors / Re: Calculating Vehicle Position with an IMU on: February 11, 2013, 12:57:11 pm
I had an old Stack data acquisition unit for my kart.  Thing is probably 10 years old or older now.  It had an accelerometer in it which it used to derive track maps.  This was a long time ago, and it didn't use a gyro or magnetometer, just an accelerometer.  The track maps visually looked very accurate, although I can't say exactly how accurate, and to scale they were, but visually it did a very good job.  Accelerometer data is very noisy, so if you are just integrating the raw data, I would imagine the results to be awful.  You are going to want to use some form of complimentary filter or Kalman filter to integrate to determine your position.

Reasonable track maps can be derived from accelerometer AND a wheel speed sensor. However, remember this is also on a track and typically defined over several lap iterations.
43  Using Arduino / Programming Questions / Re: LATLONG 2 UTM/MGRS library for Arduino? on: January 04, 2013, 11:35:02 am
is there an Arduino library that can convert LatLong data from a GPS to UTM or MGRS strings? Google didn't find anything useable.

Doubtful, I just looked at some old LL to UTM conversion code of mine and it takes up 12000 bytes. Conversion to/from MGRS would probably exceed 16000 bytes.
44  Using Arduino / Programming Questions / Re: Need help with Chess Algorithm for Arduino. on: December 18, 2012, 09:43:00 pm
Google Avr-Max or micro-max
45  Using Arduino / Programming Questions / Re: delayMicroseconds(0) = 16383µs on: December 06, 2012, 10:42:38 am

Why is anyone calling delayMicroseconds(0) in the first place?
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