Inputs Flashcards
What do input devices allow ?
Systems to understand changes in the environment around them
Examples include: sensors such as LDRs or thermistors that detect when it is too hot or cold in a room
What is the key fact with input devices ?
They take signal from the physical world and turn it into an electrical signal
They are either a switch or a sensor
Examples of signals are light legel, temp and pressure
Examples of electronic signals are voltage and current
How do switches work ?
- They allow a current to flow through them when contacts inside are joined together
- Usually named after how they woke
- Eg push to make switch allows a current to flow through it when pressed which makes a circuit
What are the types of switches ?
- push to make
- push to break
- rocker switch
- toggle switch
- tilt switch
- reed switch
What are PTM/PTB switches used for ?
Console controller buttons Eg fire or jump
What are reed (magnetic) switches uses for ?
Window sensors on alarms
What is a use of a toggle switch ?
Power switches
What is the use of a rocker switch ?
Light switches
What is the use of a tilt switch ?
To detect if something is no longer level
What do sensors do and what are they used for ?
Detect change in light level, temp and pressure
Often used in night lights and security alarms
What is an LDR?
Light dependent resistor
- special type of resistors who’s resistance changes on light level
- LDR can be used to give an input to a circuit due to change in the resistance
How does a thermistor work ?
- similar way to an LDR except temperature
- usually resistance decrease as temp increase ( NTC) but some work in the opposite way (PTC)
Example: in a heating system it can be used to check room temp and trigger turning the heater on or off
What do pressure sensors do ?
Produce a signal that varies depending on the amount of pressure placed on them
Useful for security
Example: pressure pad can trigger alarm
