I don't think your problem is the Serial.begin(9600);
Yes it is.
The ATtiny85 doesn't have a serial port.
THanks.! I just removed the serial.begin line and it still all works fine on the arduino (as I don't want to see the serial data)...( this is to control an infrared LED that triggers a Sony camera) it goes in to the ATtiny85 OK, but works very erratically.....responding randomly to the R/C input signal....and sensitive to fingers placed near!
I added some code to (I think) specify the correct pins on the ATtiny..excerpt below
#define RX_SIGNAL_IN 0
#define RX_SIGNAL_IN_PIN 1
#define NEUTRAL_RX 1500
volatile int nRXIn = NEUTRAL_RX;
volatile unsigned long ulStartPeriod = 0;
volatile boolean bNewRXSignal = false;
delay(2000); //time in mS between still photos
Moderator edit: [code] [/code]