In your example in the Playground, is there a way to preset the time in the code before compile time and not do an external synchronization of any kind?

The skinny does not have the latest auto software reset implemented as far as I can tell. If you go back to pressing reset before you upload it works fine for me.

Very good. Executing pulsein twice and taking the second value works perfectly. I measure consistent results from 10usec to 800ms with no problem. In my opinion the function should wait for the transition and then make the measurement for the duration of that high or low period depending on what you  asked for. As if starting a stopwatch on the transition and stopping it on the next transition. Thanks.

It seems that the consistency of value is inversely proportional to the duty cycle of the pulse measured. My comments earlier were at 50% duty cycle. At 10-20% duty cycle the pulse is correctly measured about 80% of the time.

In general I have had great luck with Arduino and enjoyed it very much. I am having difficulty with plusein however. It will not give a consistent result in the following sketch. I have tried both high and low transitions and have pulled the input pin to ground through a 10K resistor. I have also tried pulses from 3 usec to 100ms. In each case the output is generally about 50% correct with the balance all over the map. Thanks in advance.

long duration;
int Signal = 7;
void setup()
{
  pinMode(Signal, INPUT);
  Serial.begin(9600);
}

void loop()
{
  duration = pulseIn(Signal, HIGH);
  Serial.println(duration);
  delay(1000);
}

michelef,
Thanks, I tried the 0010 and 0011 avrdude.conf which appear to be the same and both appear to have the 644 in them. Any other ideas?

OK, I was able to upload and burn the atmega644p, but not the atmega644 with the bootloader. The clock is running at 16mhz and the led on PB2 flashes appropriately. I can compile a sketch, but when I try to upload it, I get an avrdude error saying expected signature for atmega644p is blah blah. I have a 644p in the breadboard. When I tried to burn the bootloader into a atmega644 I received the same error. Can someone suggest how I might approach this?

Thanks Mazx!

My atmega644 clock is 16mhz,crystal controlled.

My mistake, this file
http://svn.nycresistor.com/projects/sanguino/code/bootloaders/atmega644/

is uncompiled, the  other location I showed in the previous post has a compiled version,but appears to be for the 644p. At least that is what my environment with all the IDE updates and a breadboard atmega644 with the AVRisp II reports.

OK, I thought so, but the posted bootloader here:
http://macjordomo.fuortes.net/atmega644/

is an uncompiled c file. Does someone have the atmega644 (not 644p) bootloader compiled? With that
I am ready to go and try this.

Hoeken,
Can you tell me does the IDE compile the bootloader for the atmega644? Under which conditions?

These are just the ultrasonic sensors and not a complete range finder. You could build a complete ranger finder with an Arduino along the lines of what was done here:

http://www.edn.com/index.asp?layout=article&articleid=CA45965

but it maybe cheaper and easier to use the Ping sensor from Parallax or the Sparkfun Maxbotix version. Both have worked fine for me with the Arduino.

There are both positive and negative temperature coefficient thermistors. You probably have the opposite version of what you expect.

Terrific. Thanks.