Very often a variable name needs to provide more context.

I have found it very useful to use under_scores as a form of punctuation within camelCase to visually connect related variables.

Like this:

  spectrumPlot_x
  spectrumPlot_y
  spectrumPlot_drawHarmonics
  qa_signalDone
  qa_setLoadedFlag
  requestTimeout_minValue
  requestTimeout_maxValue

... and so forth.

(Note that the opposite doesn't work: camelCase as a punctuation within under_scores.)