What inputs to electronic systems are available

• Push to make switch (PTM) is a momentary switch that closes the circuit only while pressed and is commonly used in doorbells and keyboards.
• Single pole, single throw switch (SPST) is a latching switch, either rocker or toggle, that connects or disconnects a single circuit and is used in power strips and light switches.
• Single pole, double throw switch (SPDT) is a switch, either toggle or slide, that connects one input to one of two outputs, allowing switching between two circuits, and is used in mode selection for small electronic devices.
• Reed switch is activated by a magnetic field and closes or opens a circuit when a magnet is near, commonly used in security systems and proximity sensors.
• Membrane switch is a thin, flexible switch with printed circuits, activated by pressing a designated area, similar to a PTM switch, and commonly used in keypads and control panels.-

In electronics, inputs are signals or data received by a process. These inputs can be either digital or analogue.

• Digital inputs: these signals have only two states, represented as 0 (off) or 1 (on) they are used in devices like switches, which can only be in one of two positions
• Analogue inputs: these signals can vary continuously within a range, typically from 0 to 255 they are used in sensors that measure varying conditions

You may want to refresh your knowledge on electrical components

Push to make switch (PTM)

• momentary switch (it is only on when it is actuated or pressed)
• closes the circuit only while the button is pressed
• commonly used in doorbells and keyboards
• returns to the open position when released

Single pole, single throw switch (SPST)

rocker switch

• latching switch
• single pole, single throw (SPST) switch
• rocker mechanism to open or close a circuit
• commonly used in power strips and appliances

toggle switch

• latching switch
• single pole, single throw (SPST) switch
• connects or disconnects a single circuit.
• used in simple on/off applications like light switches.

Single pole, double throw switch (SPDT)

toggle switch

• single pole, double throw (SPDT) switch.
• connects one input to one of two outputs.
• allows switching between two circuits, unlike SPST version which only connects/disconnects one circuit.

slide switch

• single pole, double throw switch (SPDT) switch
• slide mechanism to select between two outputs
• used in small electronic devices for mode selection

Reed switch

• activated by a magnetic field.
• closes or opens a circuit when a magnet is near.
• commonly used in security systems and proximity sensors

Membrane

• thin, flexible switch with printed circuits
• activated by pressing a designated area
• similar to a push-to-make (PTM) switch, closing the circuit when pressed
• commonly used in keypads and control panels for a low-profile, sealed interface

Light dependent resistors (LDRs)

• sensitive to changes in light levels
• resistance changes with light intensity
• used to create light or dark sensors
• can be used as an input

Thermistors

• sensitive to temperature changes
• resistance varies with heat levels
• used to create heat or cold sensors
• can be used as an input

Moisture sensors

• Measure moisture levels using two copper contacts
• Provide a range of values (0-255) based on moisture
• Used in agriculture for soil moisture monitoring
• Integrated into circuits for real-time moisture data

Variable resistors

• two-terminal device for adjusting current
• used to dim lights or control motor speeds
• changes resistance directly in a circuit
• different from a potentiometer, which adjusts voltage
• can be used as an input

These graphs show a smooth, continuous curve. The voltage varies over time without abrupt changes. For example, the voltage from a microphone or a temperature sensor would produce an analogue graph. The key feature is the infinite number of possible values within a range.

These graphs display step-like changes, with distinct levels. The voltage switches between specific values, typically 0V and 5V, representing off/on binary states (0 and 1). An example is the pressing of a push to make switch (PTM). The graph looks like a series of square waves.