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16921  Using Arduino / Project Guidance / Re: Advice on my project on: October 20, 2011, 06:22:33 am
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However, I currently a problem with the program
Care to share?
16922  Using Arduino / Programming Questions / Re: Execution time measurement tool for Arduino software on: October 20, 2011, 05:24:41 am
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and immediately deletes the temporary folder.
That doesn't happen to me.
16923  Using Arduino / Programming Questions / Re: PIR Sensor problem on: October 20, 2011, 05:23:43 am
Perhaps the shop you bought it from can help you.
16924  Using Arduino / Programming Questions / Re: password library + lcd + 4x3 keypad on: October 20, 2011, 05:18:27 am
Psst, up there, on the right, there's a search tool.
There's also one over at the main site (link, up there, on the left)
16925  Using Arduino / Programming Questions / Re: password library + lcd + 4x3 keypad on: October 20, 2011, 05:06:47 am
I'd use EEPROM
16926  Using Arduino / Programming Questions / Re: Please need help from mentors. on: October 20, 2011, 03:31:03 am
If you're doing a debug class, make sure you put the debug strings into progmem.
16927  Using Arduino / Programming Questions / Re: please help robotic hand on: October 20, 2011, 03:28:12 am
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i have found code for moving servo's via flex sensors using the analog outputs but after 2 weeks of searching have yet to find digital ??
Can you explain what this sentence means, please?
16928  Using Arduino / Programming Questions / Re: Execution time measurement tool for Arduino software on: October 20, 2011, 03:08:57 am
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Determining the execution time for "for(int i=0;i<100;i++){}" may seem easy.
It may seem easy, but the compiler could simply optimise that particular loop out.
To avoid this, you could qualify "i" with "volatile", but that wouldn't necessarily be representative.
16929  Using Arduino / General Electronics / Re: Square Wave Signal noise 20HZ - 200 HZ on: October 20, 2011, 02:16:20 am
What does the trace from the calibration output on the scope look like?

Can we see the code?
16930  Using Arduino / Project Guidance / Re: Tracking device with arduino on: October 20, 2011, 02:02:20 am
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Don't forget to give the kid a small suitcase for the batteries
Make sure it is a lead-acid, and they won't be able to wander too far !
16931  Using Arduino / Programming Questions / Re: Understanding the BlinkWithoutDelay Program on: October 20, 2011, 01:56:11 am
"unsigned long" vs. "long":
An "unsigned long" cannot represent negative values. A "long" can.

"const int" vs. "int":
A "variable" with the "const" qualifier cannot have its value changed at runtime.

If you miss out any of the steps it won't work as it is supposed to.

The blink without delay sketch has three key lines:
Code:
unsigned long currentMillis = millis();
 
  if(currentMillis - previousMillis > interval) {

    previousMillis = currentMillis;  
 
Think about how you could do a similar task given a clock, an egg-timer, a sheet of paper and a pencil/eraser.

"delay" method:
Turn on the light.
Turn over the egg-timer.
Wait until all the sand has run through.
Flick the switch.
Repeat.

"Blink without delay method":
Turn on the light.
Write down the time now.
label: Look at the clock.
Is the time now minus the time you wrote down greater than the blink time?
YES: Flick the switch, and note the new time.
Go off, put the kettle on, read a page of a book, get the teabags out, whatever.
Repeat from "label".

"delay" is an example of a "busy wait"; the processor is continually looking at the clock to see if the required wait time has expired, and can't do other things.

"blink without delay" allows you do do other things in between looking at the clock, but make sure that the other things don't take too long to execute.
16932  Using Arduino / Motors, Mechanics, and Power / Re: Electronics noob question(DC Motor) on: October 19, 2011, 04:03:17 pm
You could use an R/C ESC (electronic speed controller) and the servo library.
16933  Using Arduino / Sensors / Re: Measure pressure from the water faucet with the arduino on: October 19, 2011, 03:25:41 pm
There were those pressurised water reactors that were popular in the nuclear industry a few years back.
I've heard of those.
16934  Using Arduino / Motors, Mechanics, and Power / Re: Electronics noob question(DC Motor) on: October 19, 2011, 03:17:13 pm
It jerks because it is drawing too much current from your arduino and may have damaged your processor.
Never connect motors directly to an Arduino.

Ever.

Use a motor shield
16935  Using Arduino / Programming Questions / Re: Where should uint8_t and boolean be defined? on: October 19, 2011, 02:29:25 pm
"uint8_T" ?
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