Arduino Uno + servo problem

Hi,

I am having issues with my Arduino Uno controlling a small servo.

When i load the servo sweep-knob sketch it works fine the first time, however if i alter the code, for example changing the maximum angle in the mapping function, the software says uploading, and then just hangs, i get the following error message - avrdude: stk500_recv(): programmer is not responding.

I cant even forcequit the arduino application and have to hard restart my macbook pro.

I am running Mac OSX 10.5.8. and the servo is a SM-S2309S

Does anyone know why this may be? The whole purpose i bought the arduino was to control servos and solenoids so its rather frustrating.

Yours sincerely, Patrick M. Keenan

Try holding down the reset button and releasing it when you get the "Binary sketch size" message.

If your sketch is accidentally flooding the serial connection you might have to hold down the reset button, unplug and re-plug the USB connection, start the upload, and release the reset button when you get the "Binary sketch size" message.

I've heard of some UNO units developing software problems in the USB processor. Search for "DFU" (Direct Firmware Update) to see how to re-flash the USB processor on the Arduino UNO.