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691  Using Arduino / General Electronics / Re: 555 timer not resetting when connected to two relays... on: January 12, 2014, 08:57:00 am
I believe this is a wiring issue.

But really though, dump the relays for Transistors.
692  Using Arduino / General Electronics / Re: 555 timer not resetting when connected to two relays... on: January 12, 2014, 08:53:49 am
693  Using Arduino / General Electronics / Re: 555 timer not resetting when connected to two relays... on: January 12, 2014, 08:51:42 am
Your schematic does not look right.

Pin 2 detects a low signal.
Pin 6 detects high (causing pin 7 to discharge it)

694  Using Arduino / General Electronics / Re: I need please explanation in this schematic on: January 10, 2014, 10:22:38 pm
I have a friend who's studying English and Aged Care, and she told me that this woman in the class who'd been here in Australia just 3 months had asked the question, who do i need to go to pay for the certification?.. she then proceeded to go on about in Asia where she was from (no specific country i'm not going to be racist) she said she just paid $2000 and got what she wanted from the actual school.

Terrifies me to think people in those countries may be working *legally* with absolutely no clue...
695  Using Arduino / General Electronics / Re: Relaying/switching 2000w at 240v on: January 10, 2014, 09:24:58 am
http://www.ebay.com.au/itm/HHC68A-1Z-AC-220V-Coil-General-Purpose-Relay-8-Pins-SPDT-15A-240V-AC-15A-28V-DC-/400580260812?pt=AU_B_I_Electrical_Test_Equipment&hash=item5d4471b3cc

3600watt (no heatsink required)

696  Using Arduino / General Electronics / Re: ON/OFF circuit when it receive 3v signal. transistor? relay? on: January 10, 2014, 09:04:47 am
ok.

mosfets need a certain voltage to switch on, hence you'll need a logic level mosfet, if 3v is not enough to saturate it, it will not be fully switched on, it'll act like a resistor letting some current through.

So, you'd use a regular transistor  from a digital pin, to switch it on with 3v, no problem and then you use that to switch on the FET. or alternatively you find a FET which can switch on from 3v.
697  Using Arduino / Project Guidance / Re: Bluetooth - quick power up and down every second on: January 10, 2014, 08:37:02 am
if you said 10 seconds.....
698  Using Arduino / General Electronics / Re: Relaying/switching 2000w at 240v on: January 10, 2014, 08:11:44 am
And a mechanical relay would barely produce much heat you'd need one rated for more than 2kw though 3kw?  should allow for any give.

Someone is going around starting fires by the smell of it (outside my window)
699  Using Arduino / General Electronics / Re: ON/OFF circuit when it receive 3v signal. transistor? relay? on: January 10, 2014, 08:05:09 am
How much current can the 3V signal source?  Switching 2A means needing to
consider the current gain of the transistor (usually low gain at high currents).

However there are some modern devices that have good gain at high currents.

However without knowing the voltage of the circuit being switched (nor whether is
AC or DC), can't make any definite recommendations.  Is the circuit being switched
sharing a ground with the control side circuit?

I was under the impression he'd be using a regular pnp/npn to switch on a non logic level mosfet or power transistor...

i
700  Using Arduino / General Electronics / Re: Powering arduino with a 36 V battery on: January 10, 2014, 06:46:46 am
I've finally solved it.
I've done a tension divider with 2  390k ceramic resistor (18 V). Arduino works, but, I know that volatge is too high so I will use a 9V regulator because we all know that Arduino has its own voltage regulator and the voltage recomended is between 7-12V.

The buck converter is also an excellent option.

Thank you for all your answers

"I've done a tension divider with 2  390k ceramic resistor (18 V)"

and that actually powers the Arduino? I don't see how there's enough current flowing and putting it through a voltage regulator will probably lead you back to square one, you'd be just as well off using just 1 resistor to accomplish the same thing.

Buy a switching regulator.



701  Using Arduino / Project Guidance / Re: How to avoid arduino from starting over each time I unplug it. on: January 10, 2014, 06:30:52 am
May i ask as to why you need to unplug it?...

A button to shut it down would be an idea, and then increment the eeprom a byte at a time to store the location until you hit the end and begin at the start, it would take many many years to wear out the eeprom like that (wiping the last value to 0 so you can search)



read my post again..

"wiping the last value to 0 so you can search" (ie.... anything that's not 0/null)
702  Using Arduino / LEDs and Multiplexing / Re: use 1 pin from arduino for bi color LED? on: January 10, 2014, 03:49:16 am
You can use the arduino to multiplex and control multiple leds or use shift registers

I guess you could buy 7 segment driver ics and pass in the value with your arduino.

Or a combination, 3 pins to a shift register, they inturn control a driver.


There's several options...
703  Using Arduino / LEDs and Multiplexing / Re: Leds in parallel on: January 10, 2014, 02:13:34 am
thanks for the respond, you are right, not enough information, my leds are 15 mA, you answered my question, but i meant to make blink each single led (assuming the pin can handle their mA) with only one pin, first one led, after the second and finally the third.

not gonna happen, each led has to be controlled by individual pins, the most that can happen is you light up all 3 dimly or destroy your pin.....

Why can't you use 3 pins of your arduino, resistor on each pin?
704  Using Arduino / LEDs and Multiplexing / Re: use 1 pin from arduino for bi color LED? on: January 10, 2014, 02:03:33 am
2 pins from your arduino instead?
705  Using Arduino / Project Guidance / Re: Controlling 1440W 120V coil resistor heater on popcorn popper with arduino uno on: January 10, 2014, 01:13:44 am
ohhh, sorry my mistake..

then cool, yeah you could use PWM on an SCR to control the current to the popcorn maker, an SCR sounds like a good way to go in which case.
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