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Analog Level Switch Component Documentation

Analog Level Switch

Section titled “Analog Level Switch”

Path: src/AnalogLevelSwitch.cpp

Revision History: Initial documentation

The Analog Level Switch component reads an analog input pin and interprets the voltage as a discrete position or “slot”. This is useful for interfacing with multi-position switches, potentiometers, or resistor networks connected to an analog input. The component provides smooth reading with configurable debouncing, hysteresis, and auto-calibration for reliable slot detection.

REQUIREMENTS

Section titled “REQUIREMENTS”
  • An analog input pin connected to a voltage divider circuit
  • Appropriate resistor selection for desired voltage levels (detailed guidance provided in header file)

FEATURES

Section titled “FEATURES”
  • Converts analog readings into discrete position slots
  • Configurable number of positions/slots (up to 32 by default)
  • Adjustable ADC value offset and step size per slot
  • Smoothing with moving average or exponential moving average
  • Configurable debouncing and hysteresis to prevent position flickering
  • Modbus integration with registers for current level and raw values
  • Individual slot state monitoring as Modbus coils

DEPENDENCIES

Section titled “DEPENDENCIES”

AnalogLevelSwitch

Component

ModbusTCP

ArduinoLog

App

BEHAVIOUR

Section titled “BEHAVIOUR”

The AnalogLevelSwitch reads the analog input at regular intervals, applies smoothing, debouncing, and then maps the analog value to a discrete slot.

n confirmations

not confirmed

Initialize

ReadAnalog

SmoothValues

DetermineSlot

Debounce

StateChanged

NotifyChange

TODOS

Section titled “TODOS”

PERFORMANCE

Section titled “PERFORMANCE”
  • Review smoothing algorithm choice based on application requirements (MA vs EMA)
  • Consider using hardware filtering for high-noise environments
  • Optimize ADC reading intervals based on use case

SECURITY

Section titled “SECURITY”
  • Validate Modbus access controls to prevent unauthorized writes
  • Consider adding range validation for configuration parameters

COMPLIANCE

Section titled “COMPLIANCE”
  • Ensure ADC readings are within the ESP-32’s input voltage specifications
  • Review compliance with relevant industrial standards if used in regulated environments

RECOMMENDATIONS

Section titled “RECOMMENDATIONS”
  • For optimal performance, use 1% or better tolerance resistors in voltage divider
  • Keep equivalent resistance of voltage divider relatively low (1k-100k range) to ensure ADC accuracy
  • Be mindful of resistor tolerance and ADC non-linearity when designing circuits
  • Use the resistor calculation guidance in the header file to design appropriate circuits

EXAMPLE

Section titled “EXAMPLE”
#ifdef PIN_ANALOG_LEVEL_SWITCH
  analogLevelSwitch = new AnalogLevelSwitch(
      this,                        // owner
      PIN_ANALOG_LEVEL_SWITCH,     // analogPin
      ALS_NUMBER_OF_LEVELS,        // numLevels
      ALS_LEVEL_STEP,              // levelStep
      ALS_ADC_VALUE_OFFSET,        // adcValueOffset
      ID_ANALOG_LEVEL_SWITCH,      // id
      ALS_MODBUS_ADDR              // modbusAddress
  );


  if (analogLevelSwitch)
  {
    components.push_back(analogLevelSwitch);
    Log.infoln(F("AnalogLevelSwitch initialized. Pin:%d, Levels:%d, Step:%d, Offset:%d, ID:%d, MB:%d"),
               PIN_ANALOG_LEVEL_SWITCH, ALS_NUMBER_OF_LEVELS, ALS_LEVEL_STEP,
               ALS_ADC_VALUE_OFFSET, ID_ANALOG_LEVEL_SWITCH, ALS_MODBUS_ADDR);
  }
  else
  {
    Log.errorln(F("AnalogLevelSwitch initialization failed."));
  }
#endif

References

Section titled “References”

The component is specifically designed for multi-position switches using voltage dividers. The header file includes detailed information on the resistor selection process for creating a voltage divider setup that can reliably detect different switch positions.