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31  Using Arduino / Sensors / Re: X-Ray detector/sensor on: February 03, 2013, 04:52:42 pm
Looks like he's mapping x-ray (speedgun?) locations.
If it were customs checks, they are likely to be fixed at known locations (ports) or at random, one-off locations.

32  Using Arduino / Sensors / Re: X-Ray detector/sensor on: February 03, 2013, 04:11:47 pm
It's a trailer.
May be scanned for illegal immigrants, drugs, munitions, or maybe to check it's speed smiley-wink
33  Using Arduino / General Electronics / Re: Rookie - start over on: February 03, 2013, 01:10:31 pm
Does this article help?

here
34  International / Deutsch / Re: PWM-Signal on: February 03, 2013, 11:03:01 am
Die Spannung in den LED ist bei 5V - egal, was PWM-Wert über Null gewählt wird.
Weil es auf schaltet und aus (Hochfrequenz) Ihre Auge nimmt die Helligkeit auf im gleichen Verhältnis wie die PWM-Wert sein. Einfache Werte wäre 0/127/255 - So würde "sehen" nichts, halbe Helligkeit, volle Helligkeit.
Dies ist für einen Motor simmilar. Die volle Leistung wird in Impulsen angewandt. Der Motor scheint zu "sehen" die Spannung als Prozentsatz der vollen Leistung 255 / n angewendet

Vergessen Sie nicht, wenn Sie ein Messgerät zu verwenden, müssen Sie AC Einstellung. Wenn Sie einen "echten" durchschnittliche Gleichspannung sehen möchten, mus man die Wellenform (einfachste Methode) chosing einen Widerstandskämpfer und capapcitor deren Werte am besten passen die Frequenz des PWM-Signals intergrate.

Der Effekt ist wie das Ausfüllen ein Bad ohne das Plug! Aber anstatt einen stetigen Strom von einem Abgriff, verwenden wir eine Schaufel (die Schaufel repräsentiert die Zeit-Frame) mit unterschiedlichen Mengen von Wasser bei einer regulären Zeit aufgetragen. die scheinbare "Spannung" wird durch die durchschnittliche Höhe des Wassers in dem Bad repräsentiert. Ich hoffe, tha gut smiley übersetzt

siehe http://de.wikipedia.org/wiki/Pulsweitenmodulation
http://hermes.eee.nott.ac.uk/teaching/cal/h61sig/sig0011.html
35  Using Arduino / General Electronics / Re: looking for a louder buzzer on: February 03, 2013, 05:07:17 am
You probably know, but you can drive each side of a piezo sounder in anti-phase to get more umph!
36  Using Arduino / General Electronics / Re: looking for a louder buzzer on: February 03, 2013, 05:02:26 am
Smoke alarm buzzer!

The ones inside these things are really loud and a wimpy 9vdc seem to have enough current to drive them.

http://ecx.images-amazon.com/images/I/41vOLU-588L._SL500_AA300_.jpg

Lefty
Beware of radioactive sources in ionizing types. May be anything up to 120 db at 1m

each 6db (aprox) is twice as loud - check the distance at which measurements are taken.
http://www.sengpielaudio.com/calculator-distance.htm

I used to make bespoke sounders for the military (supposedly 240db although I quoted then as "very loud" as my meter went off scale), they made your face hurt when testing through ear defenders. Highly illegal in the UK. My neighbours would ask, did you hear that damn alarm again yesterday? Nooooooo smiley-wink
37  Using Arduino / Programming Questions / Re: Using a global variable as the tested condition in a for loop on: February 02, 2013, 06:12:21 pm
You are pronouncing the "J" wrong, it's pronounced "Yoke"  smiley-wink
38  Using Arduino / Programming Questions / Re: Using a global variable as the tested condition in a for loop on: February 02, 2013, 05:20:39 pm
Thanks AWOL smiley
39  Using Arduino / Programming Questions / Re: Using a global variable as the tested condition in a for loop on: February 02, 2013, 05:07:08 pm
Can you post your code?

[edit]
deleted rest of reply, cus I was wro, wroooo, wrooooooo, damnit, not right! smiley-grin
Thanks AWOL
[/edit]
40  Using Arduino / Motors, Mechanics, and Power / Re: Can someone put some PWM motor control samples in the IDE? on: February 02, 2013, 04:55:47 pm
A motor need not be driven by a shield. However, as stated, it is better that example software is maintained by the vendor.

As you have noted, example software should be succinct and lend itself to experimentation.
It should also make pitfalls clear. In this case, not applying both forward and backward signals at the same time.

Hardware can overcome this problem allowing one line to select direction, the other control speed. This might be done via TTL/CMOS logic (integrated drivers, or using discreet components - the latter being a better way to learn) or a neat solution is to use a hybrid H-Bridge made of a DPDT (or two DPST) relay and a FET. An advantage of using relays is that they (tend) to be break-before-make, reducing the need to manage timing between applying back or forward signals. The positive leg of the relay H-Bridge is supplied via a FET to manage the PWM signal. Selection of the relay contact material is important, and often whetted or self-cleaning types may be advantageous.

Slightly off topic - have you noticed that some sealed relays have a little pip on them, usually in the corner? This is to improve shelf-life [edit] and to protect the contacts during manufacture [/edit], this pip should be broken open when in service to improve contact life.

Back EMF Breaking [BEMFB] may be required. BEMFB usually requires a further control line (although simple BEMFB can be implemented with two lines), and can be extremely violent! For this reason, PWM may be used to manage the motor shunt (short circuit).

As you can see, bi-directional motor control can range from crude, full speed fore & aft, right the way through to variable speed control and braking control. The more you invest in control logic, the easier it is to control safely.
41  International / Deutsch / Re: PWM-Signal on: February 02, 2013, 01:34:55 pm
PWM senden 5V bei allen Werten. Es ist die Länge des Impulses, die nicht die Spannung ändert. Allerdings, wenn Sie die Ausgabe integrieren, erhalten Sie einen mittleren Wert. z.B. 127 = 2,5 V, obwohl der Ausgang 5V für die Hälfte der Zeit von 0V für die Hälfte der Zeit gefolgt.
42  Using Arduino / Project Guidance / Re: Help: arduino php mysql (electronic toll booth) on: February 02, 2013, 01:25:43 pm
@peterH whats' the use of posting the same erroneous code again and again.i'll post it when it works.Till then suggest some useful changes instead of posting vague statements.
At this point, if I were peterH, I'd go help someone else! Be polite. The point is that if you post your non-working code, maybe someone can help....
43  Using Arduino / Programming Questions / Re: Is there a good Basic interpreter? on: February 02, 2013, 04:08:21 am
What's better for understanding the development of humans?

A flint ax?
A hatchet?
A bow saw?
A buzzsaw?

Would there be a task that I'd rather use a buzzsaw for that none of the others would be better for?
Making a chainsaw massacre movie. All arguments can be inverted.

Quote
No language (or any tool, for that matter) can do everything effectively and efficiently to everyone's satisfaction - that's why we have so many different langues / tools.
Indeed, and how many offerings of C do we have?
No language is written to create bad code! The goto was put there for good reason, and that was not to provide a method for making spaghetti. Just as it was in C!
Our understanding of what is considered to be good code has developed over time.
IMO it isn't the job of a language to impose structure, the language should be open and flexible. Maybe that is why I like assembler so much, the quality of the finished code is purely down to me. It's more than writing code, it's competition, a game, a challenge that I enjoy.
And as I said below, anyone can write "bad" or sloppy code, even, yes even on the Arduino, just take a look though these annals.
One has to separate the vagrancies of the workman from his tools before casting judgement from on high.
44  Using Arduino / Programming Questions / Re: Is there a good Basic interpreter? on: February 01, 2013, 04:58:23 pm
*fetches beer*
*pulls us a chair*
*throws a few GOTOs into the melee, sits back and watches the show"
 smiley-twist smiley-twist smiley-twist
45  Using Arduino / Motors, Mechanics, and Power / Re: Driving a 3A Stepper motor to full capacity on: January 31, 2013, 05:13:44 pm
What is a large barrel? How is it pivoted? I think that you may need to supply more data, maybe some drawings?
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