README.md

Raspberry Pi4 GPIO demo in Ubuntu-server 20.04

gpio_util

GPIO util based on rppal crate. Encapsulate rppal API into easy use interface:

// Create `InputPin` instance. Return `Error::PinNotAvailable` if fail.
const GPIO_PIN_8: u8 = 8;
let input_pin = GpioUtil::create_input_pin(GPIO_PIN_8).unwrap();
if input_pin.is_low() {}
if input_pin.is_high() {}

// Create `OutputPin` instance. Return `Error::PinNotAvailable` if fail.
const GPIO_PIN_8: u8 = 8;
let output_pin = GpioUtil::create_output_pin(GPIO_PIN_8).unwrap();

// Set pin state
GpioUtil::set_pin_state(output_pin, PinState::High);

// set output pin state and set delay after that
GpioUtil::set_pin_state(output_pin, PinState::High, Some(Duration::from_secs(1)));

• How to run cargo test?

  By default, the 'ubuntu' account can't access the GPIO device via /dev/gpiomem and /dev/mem. So for running the cargo test for this library, you have to use the command below:

  sudo -E /home/ubuntu/.cargo/bin/cargo test -- --nocapture

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How to run the sub project binary

Because the permission issue mentioned above, you can't just run cargo run.

You have to use one of the following way:

1. cargo run

   sudo -E /home/ubuntu/.cargo/bin/cargo run
   

2. Run the compiled binary

   cargo build
   sudo ./target/debug/xxxx
   

3. Run by cargo watch

   sudo -E /home/ubuntu/.cargo/bin/cargo watch -c -x run
   

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Demo videos

1. PS2 joystick

   

2. Button triggered laser Demo

   

3. Laser security alarm system demo

   

4. Raining detector demo