lcm101.h

00001 #ifndef _LCM101_H_
00002 #define _LCM101_H_
00003 
00004 #include "mbed.h"
00005 
00006 /**
00007  * Simple class to read out an LCM101 S-beam force sensor connected to an analog
00008  * input.
00009  */
00010 class Lcm101 {
00011 public:
00012 
00013     /**
00014      * @param pin_a_in PinName of analog input
00015      * @param offset of analog value (calibration data)
00016      * @param factor multiplication factor for analog value (calibration data)
00017      */
00018     Lcm101 (PinName pin_a_in, float offset, float factor) :
00019         analog_in_(pin_a_in),
00020         kOffset_(offset),
00021         kFactor_(factor)
00022     {
00023     }
00024 
00025     /**
00026      * @return unscaled analog input value
00027      */
00028     float getForceRaw () 
00029     {
00030         return analog_in_.read();
00031     }
00032 
00033     /**
00034      * @return force value kOffset_ + kFactor_ * getForceRaw();
00035      */
00036     float getForce () 
00037     {
00038         return kOffset_ + kFactor_ * getForceRaw ();
00039         //it appears that higher order polynomials show better accuracy, within the 40 kg range that is.
00040         // Awaiting other instructions, a linear fit will be currently used however.
00041     }
00042     
00043     /**
00044      * @return ffset of analog value
00045      */
00046     float get_offset () { return kOffset_; }
00047     
00048     /**
00049      * @return factor multiplication factor for analog value
00050      */
00051     float get_factor () { return kFactor_; }
00052 
00053 
00054 private:
00055     AnalogIn analog_in_;
00056     
00057     const float kOffset_;
00058     const float kFactor_;
00059 };
00060 
00061 #endif