Modify arduino code to make bell & horn momentary.

[pmachocki]

Currently the bell and horn stay on for a fixed amount of time which is a problem since the RF link can sometimes trigger a signal without human interaction.

This noise makes the horn come on and stay on when this functionality was not desired.

The change will modify the bell and horn to be only on while the stick is in the on position.

[robin731]

That's not the current design for the horn & bell logic, though it's always possible they aren't working as intended. They are currently designed to be momentary, only on when the servo value is sufficiently far from center, and in addition they have a maximum on time in case it gets stuck (10 seconds max for bell, 2 seconds for horn). That's how it appeared to be working before the Faire in October, though we had very little time to test it then. I have updated the rduorgan.ino file with the current code that's running in the robot so that you can inspect and modify the code as needed.