Watermeter
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Features
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. low power consumption (operates mostly in SLEEP mode)
. uses 2 x 16 chars backlight LCD VERTICALLY
. standard Hitachi character display used as graphical display (by using
  custom character set)
. semigraphic
. measures watertank up to eight levels
. bar graph (scale 1/8 - 8/8)
. shows liters 
. adjustable liters per graph line (stored in EEPROM) (from 00.1 to 99.9)
. 3 button operation
  - button 1 = on/off for short or long time, with or without backlight
  - button 2 = change view
  - button 3 = set
. shows battery voltage
. works with 9-wire sensor (easily constructed, consists only of stripped wires)
. uses alternating current to preserve sensor damage due to electrolytic effects
. one input (RB5) is used to automatically switch the device on (for medium
  time) when waterpump is operating


Operation
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button 1
  press once: on for short time (backlight for short time)
  press twice: on for long time (backlight for short time)
  press third time: on for long time (backlight for long time)
  press fourth time: off

button 2
  press once: go to view 2 (liters/volts)
  press twice: go back to view 1 (bar graph)

button 3
  press once: go into set mode and flashes first digit (while in set mode,
              button 1 is used to advance the digit)
  press twice: flashes second digit (button 1 to advance)
  press third time: flashes third digit (button 1 to advance)
  press fourth time: leave set mode


When waterpump starts working, device and backlight are on for medium time.


Short time = 1 minute
Medium time = 5 minutes
Long time = 60 minutes



Display
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2 views

view 1: bar graph showing water level
view 2: graph display (16 x 20 = 320 pixels) showing liters and volts