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1096  Using Arduino / Project Guidance / Re: Trigger laser (or break a beam) without anything on the other side on: August 04, 2014, 05:11:37 am
And of course there's also Passive Infra Red which doesn't need a receiver on the far side or a reflector over there and a receiver over here. Might be worth a look, at least.....
1097  Using Arduino / Programming Questions / Re: Store multiple data to EEPROM on: August 04, 2014, 04:45:06 am
And by the way use lowByte and highByte to do the splitting up before saving, and then word later on after you read them back and stick them back together again.
1098  Using Arduino / Project Guidance / Re: SwitchCase (Question) on: August 04, 2014, 03:55:15 am
When I say triplicate, don't take me too literally: remember to adjust the pin numbers and variable names  smiley-grin
1099  Using Arduino / Motors, Mechanics, and Power / Re: Help with relay on: August 04, 2014, 03:51:22 am
Quote
But it says it's opto-isolated, and the LEDs in the isolators won't want that much current:
I would tend to agree but that is not whet the specification says.

There was a poster the other day asking why his USB cable was getting hot and he claimed that the optos on his device needed 60mA.

Yep in the absence of a datasheet, it's pure (possibly expensive) speculation....
1100  Using Arduino / Motors, Mechanics, and Power / Re: Help with relay on: August 04, 2014, 03:49:55 am
Yeah use an external supply for Vcc.

Can you see the traces on the PCB?- maybe you can try figure it out by some detective work.

Does it have a maker's model number to Google a datasheet?
1101  Using Arduino / Project Guidance / Re: SwitchCase (Question) on: August 04, 2014, 03:47:22 am
Right then you should look at this example and just triplicate the part where it's looking at the buttons and when any button is LOW (LOW means pushed, that's the logic with pullups) do the stuff you need for that button.
1102  Using Arduino / Motors, Mechanics, and Power / Re: Help with relay on: August 04, 2014, 03:34:31 am
But it says it's opto-isolated, and the LEDs in the isolators won't want that much current: they would surely be driveable by an i/o pin with a series resistor?

Could it be that the low side of  the relay, the 5V which is switched by the isolator, needs to provide that much current? I see there's a Vcc pin: maybe that's the one....

Do you have a link to a datasheet or schematic?
1103  Using Arduino / Project Guidance / Re: SwitchCase (Question) on: August 04, 2014, 03:13:05 am
You'll need to give details of your hardware: a schematic will be good.... we don't know what you mean by "button", in the sense of not knowing how they're wired.

Do you have many buttons on one analog pin with a resistor ladder perhaps?- or is it a button on each of many digital pins.

Might actually be a case for "if".... "else if".... "else" rather.

Show us what you have...
1104  Using Arduino / Project Guidance / Re: Clarification on power source(s)? on: August 04, 2014, 12:30:11 am
If you plug a 9V Wall-wart into the UNO external power barrel jack you can supply close to 1 A (800mA).
You can bus everything else to the UNO +5 V.

But, you should allow and Amp for a servo, so it really does need to be powered externally from the Arduino. Just make sure you hook all the grounds together.

Edit.... pic attached
1105  Using Arduino / Programming Questions / Re: Limiting Decimal Places For LCD Print? on: August 03, 2014, 09:58:44 pm
Code:
Serial.println(myFloat,4)

That would give 4 decimals, but yep it should be 2 by default.

http://arduino.cc/en/Serial/Print
1106  Using Arduino / Project Guidance / Re: read pot help wanted on: August 03, 2014, 09:38:37 pm
Wouldn't a non-linear pot still give analog 0 at one end and and 1023 at the other though, but just not be linear between the extremes? Surely the ends are the same no matter what the pathway? (Not that I've ever used one, just seems sensible to me.)
1107  Using Arduino / Programming Questions / Re: controling 2 relays independantly on: August 03, 2014, 12:19:03 pm
Thanks John
1108  Using Arduino / Programming Questions / Re: controling 2 relays independantly on: August 03, 2014, 09:52:46 am
Quote
  digitalWrite(Relay1Pin,RelayOff);
  pinMode(Relay1Pin,OUTPUT);

John is there a reason for putting the digitalWrite before the pinMode?
1109  Using Arduino / Project Guidance / Re: where/how to place "blink without delay" on: August 03, 2014, 08:44:52 am
This code several things at a time is an extended demo of BWoD. It may help you to grab the concept.

...R

I already linked to that in Reply3....
1110  Using Arduino / Project Guidance / Re: where/how to place "blink without delay" on: August 03, 2014, 08:33:09 am
Tried the millis approach but it gets rather complex quickly with the many states

It can, yes, but if you implement a state machine as suggested by GM on his myzen site, or by Nick Gammon it keeps things ordered.
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