G'Day,
I've been trying the mod with good results except when I drag the top of the window upwards to the top of the desktop to have the window full length (Win 7 Home premium 64bit). When I do that it freezes until I reduce the height o f the window.

Cheers ............ Mike B

Very handy, works well (takes me back to Win98 !!!).

Cheers ........... Mike B

Yeah,
That's what I do, I am just curious.
I imagine most would have a long list of sketches after a while.

Cheers ....... Mike B

G'Day All,
After starting Arduino 1.1
When I hit the up arrow in the toolbar to load a sketch the list fills the screen (height wise) and I can't scroll down to the bottom of the list.
I'm using Win7, can that be fixed ??

Cheers ............ Mike B

G'day All,

Under the tools menu is the option to choose a programmer like "AVR ISP" etc.
I can't turn up any reference to the use of the various programmers.
How do I decide which to use for a specific board ??

Cheers ............ Blakey

Duhh !!

Problem solvered, I had omitted the base resistor so I guess the transistor was suffering and pulled the pin down.

G'Day All,

I can't get my head around why this code will not acknowledge the PIN value when it's high.
I'm just practicing to learn.
The code works when the PIN is low but not when high, ie there is no serial  print ( +++ etc)  when the pin is high.
The routine controls the fan as coded except for the serial print when the PIN is high.

/*
Sketch to run 12v fan.
 Fan + to 12v, fan - to BC547 Collector.
 BC547 Emitter to ground and Base  to pin #8.
 
 MB 17/03/12
 */

int switchPIN = 8;


void setup()

{
  Serial.begin(9600);
  pinMode(switchPIN,OUTPUT);
  Serial.println("         CONTROLLING A FAN     ");
}


void loop()
{

  digitalWrite(switchPIN, HIGH);
  Serial.println("  FAN ON");
  int pinval = digitalRead(switchPIN);
  if (pinval == HIGH) {
    Serial.println("+++"); 
  }
  delay(3000);
  digitalWrite(switchPIN, LOW);
  Serial.println("  FAN OFF");
  pinval = digitalRead(switchPIN);
  if (pinval == LOW) {
    Serial.println("---"); 
  }
  delay(3000);
  digitalWrite(switchPIN, HIGH);
  Serial.println("  FAN ON  LONG");
  pinval = digitalRead(switchPIN);
  if (pinval == HIGH) {
    Serial.println("L+++"); 
  }
  delay(9000);
  digitalWrite(switchPIN, LOW);
  Serial.println("  FAN OFF  LONG");
  pinval = digitalRead(switchPIN);
  if (pinval == LOW) {
    Serial.println("L---"); 
  }
  delay(9000);

}

Thanks again,

I am probably chasing my tail with the jitter, although I would like know if there is any caused internally in the chip.
I can see a few millivolts on the input and since all my readings are being done next to a computer that is probably where some of the jitter is coming from.
I can see that using the 5v ref will be better in terms of reducing the response to the jitter, maybe I'll take the input volts lower to see if that stabilises it a little.

Cheers ........ Mike B

Thanks,
Yes charge is PWM and I will take a look at the input waveform.
Could you expand on the "Timing the analog read" please?
At the moment I have the PWM output disabled whilst measuring the input,
the fluke 3.5 digit VOM shows a steady input at the analog input but the
binary value is going up and down as mentioned. I am viewing the voltage
every second or so whilst I develop the code.
Yes the circuit is on a breadboard and unshielded but I notice this effect in
other projects I have made on veroboard enclosed in a diecast box.

Cheers ........ Mike B

G'day All

I need to monitor a battery voltage to control charge rate.
I have set up the usual volt divider on the 12v battery I am monitoring and decoupled it with 1uF.
The binary result is constantly going up and down by about 5 or 6 even with a regulated source.
I have tried smoothing and averaging without any success.
Since my interest is in the decimal part of the voltage being measured (the usual 13.80v) am I kidding myself or is it possible to tame whatever it is causing the jitter??
What is it that causes the jitter, say using the 3.3v ref on the duemillanova board ??

Cheers ....... Blakus

Ok mebbe you should do a bit of research on the basics of transistors and components 

On the other hand it's not rocket science either !!

I reckon for speed control of a fan ( 2 amps) just use a power mosfet, which are really cheap on eBay and control that with
the Arduino PWM output. AFAIK there are schematics in the tutorials to do just that.

You could use the direct output of a digital port to drive the mosfet since very little current is required to switch the
mosfet. Really a better way to do what you want. Check this link below to see what I mean about the mosfet.

http://www.ebay.com.au/itm/IRF640-IR-Power-MOSFET-N-Channel-18A-200V-/140616112859?pt=LH_DefaultDomain_0&hash=item20bd5f9adb  or search for some there.

Cheers ........ Blakus

You need to select a transistor that will carry the current you need.
Look at the data sheet and note the gain, that is the ratio of base current to load current.
So if you have a power transistor that will take say 3 amps with a gain of 100 then you will have
to pass about 30 mA into the base to pass that load of 3 amp.
Usually you add a bit more current through the base to make sure the transistor is fully turned on.
So if you are using 12v supply the resistor for the base will be roughly 12v/.03a = 400ohm.
That is for switching, if you will be varying the speed then a larger heat sink will be required
for the transistor. If you only want to switch on and off then a power mosfet would be a better choice.
Also a darlington configuration would be better at that level of current.

Have a look through the RedRock site, thev'e been into such things for years. You might get a few ideas ??

www.redrok.com

Cheers ....... Mike B

Yeah, the reference goes to an analogue input. (12v gives around 2.5v)
I'll be using the 5v reg ref as supply to the transistor.
I'll just read off the binary values when it's working and plug them into the code.
I only just need to know terminating and commencing points of charge so I'll
give it a try and see what happens. It may well be heat sensitive so I'll do some
field tests on one.
Thanks for the interest.

Cheers .......... Mike B

The schema for the isolated volt sensor attached.