todo.txt

Things to do or ideas to implement:
* distance measurement
* add state summary (only calibrating / released / approached / pressed)
* add virtual sensor (combine multiple / all sensors) to use as distance sensor
* correct gain and / or offset in normal / inverted modes?
* gestures (wheel / slider / touchpad / keyboard)
* example code with button to measure SNR
* auto enable slewrate based on noise variance?
* IIR filter
* charge pin when number of sensors is 1 (provides speed up of almost 2 x)
* documentation (manual + presentation)
* update paper on nCharges based on capacitance instead of distance
* example code with wireless communication to measure common mode noise?
* combine multiple sensors for proximity sensing?
* add option for RC guard
* make N_MEASUREMENTS_PER_SENSOR optional (default to 16)?
* allow shorter time for recalibration if forceCalibrationAfterRelease is set?
* move some parameters from per sensor to TouchLib object
* add wireless to debug conducted noise immunity
* add reportedCapaticance and reportedDistance which are equal to capacitance
  and distance when capacitance and distance are larger than 0, and 0 elsewhere.
* overload constructor with custom scanorder
* use better logic for isPressed() / isReleased() that uses tresholds
  corresponding to current state
* force recalibration if average is too low (too much negative)?
* convert floating point to fixed point operations
* use unused analog input to calibrate parasitic capacitance (C_c); can also be
  used to track temperature drift (if necessary)
* make charge / discharge delays function of nCharges? (bigger capacitors need
  longer charge times)

* merge sensors: charge C_a, discharge in several sensors then measure voltage.
  Alternatively: charge sensors, discharge in C_a
* coded sensing: charge C_a, discharge in several sensors then measure voltage.
  Do this N times, each time selecting a different sensor to charge ADC and thus
  also a different discharge order.

* enable slewrate limiter by default
* store settings in eeprom
* generate setup code
* different sample functions for CVD, touchRead, resistive read, ... (+ allow
  for custom sample functions via function pointer?)
* add callbacks (function pointers) when button state is changed
* add ResponsiveAnalogRead method?

* fix bug in printing floating point numbers with fixed width (SNR example)
* test all 6 channels on ATmega32u4 (lilypad) (mux is slightly different than on
  mega2560?)