Digital Inputs: Buttons, Switches and Decisions

10 Lektionen in dieser Stufe

1. Reading a Push Button with digitalRead
   Configure a pin as input and read its logic level. · Lab: Wire a button to 5 V with a pull-down resistor and mirror its state on an LED.
2. Floating Inputs and the Pull-Down Resistor
   Explain why an unconnected input gives random readings and how a resistor fixes it. · Lab: Remove the pull-down, watch the LED flicker when you move your hand near the wire, then restore it.
3. INPUT_PULLUP and Inverted Logic
   Use the internal pull-up and handle a button that reads LOW when pressed. · Lab: Rewire the button to GND with no external resistor and adapt the sketch.
4. Decisions with if, else and Comparison Operators
   Branch program flow using conditions and comparisons. · Lab: Light a green LED while a button is released and a red one while it is pressed.
5. Boolean Variables and Logical Operators
   Combine conditions with and, or and not and store results in bool variables. · Lab: Require two buttons pressed together to switch on an LED, then either one of them.
6. Detecting a Press Edge Instead of a Held Level
   Remember the previous state to react once per press. · Lab: Count button presses and blink the count back after a pause.
7. Contact Bounce and a First Software Debounce
   Recognise bounce as multiple false edges and suppress it with a short wait. · Lab: Show miscounts from a bouncing button, then add a debounce and compare.
8. Toggling and Cycling Modes with One Button
   Use a counter variable to step through several behaviours. · Lab: Make one button cycle an LED through off, on and blink.
9. Slide, Tilt and Reed Switches as Inputs
   Wire other switch types and understand they are all just contacts. · Lab: Build a tilt alarm LED and a magnet-operated door indicator.
10. Selecting Behaviour with switch-case
    Replace long if chains with a switch statement and avoid fall-through mistakes. · Lab: Rewrite the mode lamp with switch-case and add a fourth mode.

Abschlussprojekt

A pedestrian crossing with a request button plus a lamp whose three modes are cycled by one debounced button.

Teile für diese Stufe

• 1 × UNO-compatible board
• 1 × USB cable matching the board
• 1 × Solderless breadboard 830 points
• 1 × Jumper wire set male-male
• 4 × Tactile push button
• 4 × Resistor 10 kilohm
• 6 × Resistor 220 ohm
• 6 × LED 5 mm assorted
• 1 × Slide switch
• 1 × Tilt switch
• 1 × Reed switch with magnet

In jeder Lektion legst du die passenden Teile direkt in den Warenkorb. Arduino-kompatibel →