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286  Using Arduino / Motors, Mechanics, and Power / Re: Elettrovalvola irrigazazione on: May 29, 2014, 02:16:29 pm
5 VoltAmpere or  5 Watts means (5VA / 24 V=) 0.21 Ampere.
That is not nearly enough to supply power to any valve i know of.
This is also the reason you see a short when trying to use this supply with your valve.

If you have a multimeter, measure the resistance of your valve.
That will give you an idea to what current you need, but make sure you can supply some more than that.
287  Using Arduino / Motors, Mechanics, and Power / Re: Elettrovalvola irrigazazione on: May 29, 2014, 12:28:45 pm
Quote from: Ross95
Hello, I have a 24V solenoid valve for irrigation. If supplied with 20V instead of 24V does it work?
Also, when I connect it to the transformer 220-24V, it creates a short circuit, does anyone know why?

Hi and welcome.
Please speak English in the international part of this forum.

Your valve will probably work at 20 volts, because the voltage isn't that critical.
As things go with electronics, the power is what is important.
And power is the product of voltage and current.
If you lower the voltage (of course within limits), there will be need for some more current in order to get the same power.

A valve normally is controlled by a coil.
That has a relative low resistance (a 24 volt coil with a resistance of just over 15 Ohms so drawing about 1.5 A is quite normal), and a short is a very low resistance.
You need to know some of the characteristics of that valve/coil in order to do the math on it.
If you know the power and a voltage the coil is rated at, you can find out what current you need to supply.
And of course if the current is specified (in Amperes) you'll know that too.
See if the power and / or current can be supplied by your power supply at all.

A coil also briefly draws more than the nominal current when switched on.
So if your power supply is just strong enough to power the coil, it might shut down due to over current when switching the coil on.
288  General Category / General Discussion / Re: Can't locate RX0 on the baord. Looking for Digital 0 pin. [pro mini 5v] on: May 29, 2014, 07:17:49 am
Yes, they are the same (hence the same label) the pins on the short side of the board are placed there for convenience while connecting it to a serial adapter, as you did.
You have to make sure that this pin is exclusively used for the goal you need it to be.
That means remove the USB/serial adapter while in normal use (e.g. not uploading your sketch).
That again means you need to work out an alternative way to power the Pro Mini.
289  Using Arduino / Displays / Re: VGA TO COMPONENT conversion on: May 28, 2014, 04:01:24 pm
Let's start with the entry level Arduino offers.
Just one of the very important lesson you will learn during your Arduino discoveries:
There are limits to what you can do using this hardware.
290  International / Nederlands / Re: Profielwerkstuk on: May 27, 2014, 05:10:08 pm
Hoi Valentin, welkom op het forum en bij deze leerzame hobby.

Er zijn hier genoeg mensen die je kunnen helpen met je vragen.
Maar je moet je wel realiseren dat dit een forum is.
En dat betekent dat het van en voor iedereen bedoeld is.
Je vraag om een en ander 1 op 1, bijvoorbeeld via skype te gaan doen, is niet helemaal waar een forum voor bedoeld is.
Ik snap heel goed dat je dat wil, omdat je op dat moment zo'n beetje 100 % van iemands aandacht krijgt.
Maar diegene is dan dus ook alleen met jou bezig, en na jou is er niemand die er wat van zal opsteken.
Heel misschien degene die je aan het helpen is.
Als je zoekt op het woord "distiller" (te vinden op de eerste Nederlandstalige pagina), kun je zien dat er ook geholpen kan worden via het forum.
Het grote voordeel daarvan is dat anderen er ook wat van kunnen opsteken, en natuurlijk ook dat meerdere personen hun bijdragen kunnen doen.

Overigens, het is niet zo'n goed idee om je mail adres open en bloot op een forum te zetten.
Das vragen om spam, ook al heb je (of je mail provider) nog zo'n goede spam filter.
291  Using Arduino / Displays / Re: VGA TO COMPONENT conversion on: May 26, 2014, 04:13:18 pm
Where's the question ?

The difference between VGA and component is very different from timing.
So your assumption is incorrect.

What do you want to do by analogReading using your Uno ?

Do you really think you can improve a VGA signal to become a (potential HD) component signal, using an Uno ?
292  International / Nederlands / Re: Communicatie met atmega 328 en due (serieel) on: May 26, 2014, 03:51:03 pm
De Atmega328 kan werken tussen 1.8 en 5 volt.
Je hebt het hier over de controller, en je hebt niet een Arduino product (anders dan de Due) genoemd.
Als je wel een Arduino product wil gebruiken, dan kun je kiezen voor de (lekker compacte) pro mini (klik!), die kun je bestellen in een 3.3 volt versie (op 8 MHz) en een 5 volt versie (op 16 MHz).

Kies je dus voor een 3.3 volt oplossing, dan heb je in ieder geval helemaal geen probleem met de seriële verbinding en spanningsverschillen.
293  International / Nederlands / Re: Potmeter analoge waarden controleren on: May 26, 2014, 03:37:03 pm
Hoi en welkom.


Ik vermoed dat je hier een soort van calibratie wil doen, om te compenseren voor externe omstandigheden (zoals temperatuur), of om te zien of de potmeter nog wel goed is.
Je meetbereik is van 0 tot 1023.
Maar als er iets fout gaat (een mechanische fout betekent vaak een onderbreking in de weerstandsbaan), dan zal je waarde óf 0 óf 1023 worden.
Uiteraard zijn er wel andere resultaten mogelijk bij fouten, maar het is maar de vraag of je dat op een dergelijke wijze gaat "vangen".

Quote from: Jantje
wegens afwijkingen in de electronica (potmeter, ADC poort, ....) is er geen garantie dat je ooit 0 of 1023 leest van analogRead.

Je kunt nu een beetje van de meetwaardes weggooien, om een calibratie te doen.
Dan zet je voor en na je potmeter een extra weerstand (van een lage waarde).
Dus tussen 5 volt en potmeter, en tussen GND en potmeter een weerstand.
Dat kost je wel een stukje bereik, maar je kunt zo dus wel goed vaststellen wat de slag van je potmeter doet en kun je dus omgaan met waar Jantje je hierboven op wijst.
Een breuk in de weerstandsbaan zal dan nog steeds 0 of 1023 opleveren, en zal tijdens het verdraaien van de potmeter een plotselinge omslag laten zien (geldt ook als er geen extra weerstanden worden gebruikt).

Overigens is het van groot belang dat je er voor zorgt dat de voedingsspanning stabiel is.
Anders krijg je alsnog afwijkingen in je metingen.
294  Using Arduino / General Electronics / Re: WIRING of KY-040 Rotary Encoder plus Demo Code on: May 25, 2014, 06:07:48 pm
Hi and welcome.

Did you read this (click !) ?
Don't answer that question, it's a truism, i already know you didn't.
Please do and edit your post accordingly.
That will make your post / example as useful as you hoped it would / meant it to be.
295  Using Arduino / General Electronics / Re: Multiple sensors on Arduino on: May 25, 2014, 06:00:34 pm
Thank you for sharing that.
It's not that hard to do, so lots of success with it.
If you do run in trouble, don't hesitate to ask on this forum !
296  Products / Arduino Due / Re: LiquidCrystal library for Arduino Due on: May 25, 2014, 05:54:16 pm
Both the magic wand and the crystal ball have been in the shop for repairs the past year.

Maybe you could be troubled to tell something yourself about what errors are shown ?
And what about how you did
Quote from: aristomenis
just import the library ( #include <LiquidCrystal.h>)
?
Did you check you have that library at hand ?
297  Using Arduino / Displays / Re: ezLCD3 does not name a type on: May 24, 2014, 07:01:06 pm
Hi Alexdut68,

You probably didn't get that library or didn't tell IDE where to find it.
298  Using Arduino / Motors, Mechanics, and Power / Re: Need to remove acceleration with AccelStepper driven motor on: May 24, 2014, 05:17:38 pm
Do so while your motor is on load.
If it is running free (without the load), you'll be doing work for nothing.
299  Community / Website and Forum / Re: How to show images attached to the post inline with the text of the post? on: May 24, 2014, 04:45:53 pm
Quote from: Paul__B
Now if you are really sneaky, I fancy you can attach the image, thus loading it to the Arduino server, then use the attached link to provide an inline image, and in modifying your post, remove the attachment at the bottom.  Or not.

So let's test that:
Attached a smaller picture that i've attached in some other post before.
Now i'm going to try to use that picture by pasting it's link into these img tags:
[img]http://forum.arduino.cc/index.php?action=dlattach;topic=242171.0;attach=82816;image[/img]

Let's have a peek then.
Seems to work for me.
And still seems to work after deleting the attached picture.
Might be due to some browser cache though.

Yet another test.
Tested with another browser, so no cache there, and the picture became a small red cross instead of what was uploaded.
So removing the attachment also removes the picture.

The other browser i used is an old IE.
I re-attached that image, and changed the links.
Still doesn't work (as i expected, to be honest) with that other browser.
Now it seems to be OK.
So with both browsers i can see both pictures.
300  Using Arduino / Displays / Re: TextStar Display on: May 22, 2014, 04:22:51 pm
Hi.

TextStar or TestStar (you mentioned both) doesn't ring a bell to me.
Is that a type or a brand ?
In case it is a brand, then what type are you talking about ?
Do you have a picture, and can you show that (or a link to it).

An Arduino has a TTL level RS232 port, and just RX and TX.
Handshaking and such stuff aren't there (initially i typed "are missing", but who misses those ?).
This has a very simple reason:
You only need a standard port which can also be used for other purposes, ad you will save a dedicated port with some additional level shifting hardware.

So if you need a real RS232 port, you'd have to add that piece of hardware yourself.
That would be a MAX232 (or some derivate) and supporting components, of which some 4 capacitors (acting as charge pumps) are the most important ones.
Google MAX232 for 5 volt level or MAX2323 for 3 volt level, you'll find lots of information.
 
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