Sparkfun Electronics RedBot Getting Started page 14

Another sensor provided for the RedBot is a specially designed accelerometer board. This board
couples a Freescale MMA8452Q accelerometer with a TI PCA9306 level shifter and is designed to
attached directly to the A4/A5 header on the RedBot. In addition to normal accelerometer data
collection, it can be used to detect bumps (as in collisions) or taps (for user input).
RedBotAccel();
The class constructor accepts no parameters; simply instantiate an object of the class and the
2
library will handle all necessary configuration. Including the I C library provided by Arduino is not
necessary either; all that is handled by the library.
void read();
Unlike most read-type functions, does not actually return a value. What it does is copy the
read()
most recent accelerometer values into three variables (naturally enough, named , and . Those
x y z
values can then be easily referred to using the class object name.
void enableBump();
boolean checkBump();
void setBumpThresh(int xThresh);
These three functions allow the user to enable and check bump detection. Under normal
circumstances, the function shouldn't be needed; the bump threshold is already set
setBumpThresh()
to a good value. Users may find it useful to increase or decrease the sensitivity level; the range for
that number is 0-127.
returns a if a bump has been detected since the last time was called. It
checkBump() true checkBump()
may be useful to call to clear any existing bumps before attempting to detect a bump for
checkBump()
Page 14 of 19