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1  Using Arduino / Project Guidance / Re: Heating water? on: March 20, 2013, 12:17:41 am
Thanks for replies! smiley

I think I'll go with the coffee maker's heating element and separate power for Arduino, which controls the element with SSR.
And yeah, I meant closing the circuit when I said open... Another example of me being tired.

And I need the water to be hot so all the good taste can absorbed into it (but NOT boiling). smiley
2  Using Arduino / Project Guidance / Re: Heating water? on: March 19, 2013, 04:36:03 pm
Put it into a small project box, observing isolation distances from 240V to low voltage parts!!!

The SSR is like a LED with a built in resistor. It will not load the output on the Arduino much less than a LED and fitting resistor, so no need for anything extra. You can connect it up directly.

// Per.

Put it into a small project box, observing isolation distances from 240V to low voltage parts!!!

The SSR is like a LED with a built in resistor. It will not load the output on the Arduino much less than a LED and fitting resistor, so no need for anything extra. You can connect it up directly.

// Per.

Thanks!

I'm a little tired... So simple, but effective solution... smiley I like it.
I was worried about the SSR because I've read that Arduino can't supply enough amps to open those normal relays, but I think SSR is a little different. (It seems to require just under 5mA to open it, which is good)
3  Using Arduino / Project Guidance / Re: Heating water? on: March 19, 2013, 04:26:49 pm
Normal Coffee makers run on 120/240V single, there is no low voltage inside. Some of the more advanced ones with timers etc. have a low voltage, but this voltage is NOT isolated from the mains, so if you connect to that you're getting yourself killed sooner or later, so DON'T toy around with it!

// Per.

Mm'kay, you made your point clear. And yeah, I was thinking one of those cool timer/IC boards...

How can I then power Arduino from the same wire, let's say 240V?
Do I really need an DC adapter to 12V and I would also need to split the 240V for the heating element too?

I also need to power a few servos and maybe a 5 - 12V dc motor. I think I also need a relay for the heating element (which maybe needs to be controlled by transistor)?

You power your Arduino from a DC-Wallwart that supplies it with 7,5V optimally (then you don't waste all that power in the voltage reg.)
You control the Coffee maker from a SSR, like this http://goo.gl/E4k8p

// Per.

But I would still need to split a 240V line to 2 cables, one to Arduino and the other to the coffee maker. I would like to have a compact/fairly small 1-cable solution:
240V AC input -> 7.5V DC output for Arduino and 240V AC output for the coffee maker heating element controlled by Arduino.

Thanks for the relay tip, you think Arduino could handle it without transistor?
4  Using Arduino / Project Guidance / Re: Heating water? on: March 19, 2013, 04:04:26 pm
Normal Coffee makers run on 120/240V single, there is no low voltage inside. Some of the more advanced ones with timers etc. have a low voltage, but this voltage is NOT isolated from the mains, so if you connect to that you're getting yourself killed sooner or later, so DON'T toy around with it!

// Per.

Mm'kay, you made your point clear. And yeah, I was thinking one of those cool timer/IC boards...

How can I then power Arduino from the same wire, let's say 240V?
Do I really need an DC adapter to 12V and I would also need to split the 240V for the heating element too?

I also need to power a few servos and maybe a 5 - 12V dc motor. I think I also need a relay for the heating element (which maybe needs to be controlled by transistor)?
5  Using Arduino / Project Guidance / Re: Heating water? on: March 19, 2013, 03:46:57 pm
Thanks, that's almost what I was looking for but I need also around 7 - 12V for an Arduino, that's why I was thinking using a coffee maker.
I think coffee makers have a little control PCB in there, which runs on around 12V, which I could use to power Arduino, without a need for external PSU or converter / regulator.

I think I'll disassemble some old coffee makers tomorrow, if I find any of course... smiley-wink
6  Using Arduino / Project Guidance / Heating water? on: March 19, 2013, 03:10:17 pm
Hi!

I got a pretty nice idea, which involves heating some water (kinda like a coffee maker).
I don't need any large amounts, one liter should be enough, but how can I get it to about 90 - 95°C and so it can still be drinked?

I was thinking maybe I should borrow the heating element from an old coffee maker, but I thought to make this thread, if there is any other way.
Or if I could buy just the heating element somewhere... No need to buy a whole coffee maker.

I think I must use a big heating element like those 1kW coffee makers? Even the best 12V coffee makers can take over 20A, which is pretty much... (and still just ~250W power).

Also, what kind of tubing will handle around max 100°C water? And doesn't dissolve anything to the water so I can still drink it?

Thanks for the answers in advance! smiley
7  Using Arduino / Project Guidance / Re: Lights for drums - Beginner need some advice on: March 16, 2013, 06:24:35 am
I think few 5050 SMD RGB led strips could be enough (pretty cheap too). I suggest getting 5050 strips, 3528 won't be bright enough.
You can find 5 meters of the RGB strip for under 20$ on eBay. If you don't need multiple colors, just buy those one-color strips.
8  Topics / Device Hacking / Re: DVD Player Haxoring, VFD display. on: March 09, 2013, 07:37:43 pm
I digged one of my my all-kinds-of-things boxes and found a display with SM16312 chip (or SMI6312). It's pretty similar to yours.
Unfortunately I couldn't find any other parts related to this display, so I don't know about the power supply or other things.

The board has total 10 wires, some labeled:
GND - ground
DATA - serial data (?)
D** (can't read, it's worn off)
LCK - serial clock (?)
RMOE - IR remote
+5V - voltage in

and 4 other wires without label, coming from a different place (two of them going straight to the display (the AC power or something?)).


It would be nice to use this display in something... Well, at least the board has a few buttons to use in other projects.
9  Using Arduino / General Electronics / Re: 3-Wire PC fan on: March 08, 2013, 08:55:11 am
Take a look at Arduino PWM, you could probably use this with the yellow wire or just the red wire too.
10  Using Arduino / Project Guidance / Re: Pulse limiter? on: March 08, 2013, 07:25:05 am
Thanks for help! smiley

I've tested & edited my code little and I think it works now. I'll test it with the device later today and report back! smiley
11  Using Arduino / Project Guidance / Re: Pulse limiter? on: March 07, 2013, 08:53:05 am
Thanks for reply! smiley

The actual problem is that the device is closed (no possible way to open and even check what it contains), and there is no datasheet.
And another problem is that I'm not 100% sure about the ratio of LOW/HIGH, so it's not accurate with only the frequency.
I could calculate the ratio and edit the code then though. And the device shouldn't be affected from the Arduino's +5v, everything else than GND is fine (except if it burns the wires or something...).

I'll try and post code soon! smiley



Code:

Code:
int currentMicros, previousMicros, lowTime;
int currentTime, previousTime;

int input = 2;
int output = 3;

void setup() {
  pinMode(input, INPUT);
  pinMode(output, OUTPUT);
  digitalWrite(input, HIGH);
  digitalWrite(output, HIGH);
  attachInterrupt(0, calculateFrequency, RISING);
  Serial.begin(9600);
}

void loop() {
  currentTime = millis();
  if(currentTime - previousTime > 500) {
    previousTime = currentTime;
    Serial.println(lowTime);
  }
}

void calculateFrequency() {
  previousMicros = currentMicros;
  currentMicros = micros();
  lowTime = currentMicros - previousMicros;
}

I'm also using my Arduino Mega (2560, if it matters), to output some kind of pulse with this code:
Code:
void setup() {
  pinMode(2, OUTPUT);
  digitalWrite(2, HIGH);
}

void loop() {
  digitalWrite(2, HIGH);
  delayMicroseconds(450);
  digitalWrite(2, LOW);
  delayMicroseconds(50);
}

Uno is running the first code, and it writes about 512 - 520 to the serial, which is pretty close to right? How can I get the code more accurate,
even 10 microseconds wrong can make the whole device fail... smiley-grin I was thinking something like this:
Code:
pulse = pulse - 15;
which would then make the output pretty close too 500 (+/- 5 probably).
12  Using Arduino / Project Guidance / Re: Pulse limiter? on: March 07, 2013, 07:15:49 am
Thanks for quick replies!

By "limiting" the pulse I meant the frequency of it, so yes... Arduino should make the output itself.
I think the high voltage doesn't matter in the other system, just the ground signal.
If Arduino and the external system have a common ground, Arduino should be able to make right kind of a pulse.

Copying of the input should be possible with "change" interrupt, but how about "recording" the length of HIGH and LOW from the input,
and the outputting the same pulse, with FALLING and RISING interrupts (for example)?
13  Using Arduino / Project Guidance / Pulse limiter? on: March 06, 2013, 02:58:14 pm
Hello!

I'm building a project to limit pulse, but the pulse itself seems to be pretty weird. The pulse comes as a grounded signal, otherwise the wire is just not connected.
How can I make Arduino to read this signal and then make it continue, but if the pulse's frequency is high enough, limit it?

The pulse is about 25 - 250hz, but the duty cycle is about 2%. So the pulse is LOW around 2% and 98% it's everything else than LOW,
but I think Arduino cannot read it as HIGH, because it's under 1v or so...

Another problem is that the pulse changes pretty quickly, so the code should need to have ability to respond to the changes pretty quickly too.
I think using delay() or delayMicroseconds() would just make the system fail, so delays aren't really usable. Interrupts could work, but I haven't got it working yet...

Thanks in advance! smiley
14  Using Arduino / Displays / Re: womarts LCD touch on: January 24, 2013, 12:23:42 am
Hi! smiley

I didn't even try the sample code, I used UTFT from the beginning. UTouch, TinyFat and other Henning's libraries work well. smiley

Also, the board is technically not a "clone", but a counterfeit. If it had something else printed than "Arduino", it would be legal.
It's illegal to make boards with text "Arduino", but legal without it. Freaduino, for example...
15  Using Arduino / Displays / Re: womarts LCD touch on: January 23, 2013, 08:11:37 am
Hello!

I received my LCD & Mega 2560 yesterday! smiley

The Mega itself seems to be working just like it should, Windows recognizes it as a genuine Arduino Mega 2560 R3, but I still think it's a counterfeit...
Genuine Mega2560 under 35€ with the 3.2" touch-screen LCD? No way...

The fonts on the board seems to be a little different than the genuine Arduino's. Also the print is kinda pale or something...
Also the logo doesn't seem to be "the real one", it looks just like 2 circles printed with 0 space. smiley-grin

Then the LCD... The board is red (which I don't really like, whatever...), and seems to be extremely sturdy.
The pins were about 0.2mm wrong, it was pretty hard to attach it perfectly. However, the pins bended to correct position after first attachment.
The LCD is pretty bright and the colors are vivid.

I can only recommend this to anyone who wants a cheap Mega + Touch LCD! smiley
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