README
¶
Button SHIM Go library
Provides a Go implementation for interfacing with Pimoroni's Button SHIM. The top-level library provides a lot of the same functionality as the reference Python library, including:
- Handle press/release events for the buttons
- Update the color of the RGB LED.
Overview
Installation
First, clone the project into your Go path:
go get github.com/tomnz/button-shim-go
The library depends on the periph.io framework for low level device communication. You can install this manually with go get, or (preferred) use dep:
go get -u github.com/golang/dep/cmd/dep
cd $GOPATH/src/github.com/tomnz/button-shim-go
dep ensure
Usage
First, initialize a periph.io I2C bus, and instantiate the device with it:
package main
import (
"github.com/tomnz/button-shim-go"
"periph.io/x/periph/conn/i2c/i2creg"
"periph.io/x/periph/host"
)
func main() {
// TODO: Handle errors
_, _ := host.Init()
bus, _ := i2creg.Open("1")
shim, _ := buttonshim.New(bus)
}
The library implements button press and release handlers using channels. For example:
aPress := shim.ButtonPressChan(buttonshim.ButtonA)
bPress := shim.ButtonPressChan(buttonshim.ButtonB)
aRelease := shim.ButtonReleaseChan(buttonshim.ButtonA)
go func() {
for {
select {
case <-aPress:
fmt.Println("Button A pressed!")
case <-bPress:
fmt.Println("Button B pressed!")
case holdDuration := <-aRelease:
fmt.Printf("Button A held for %s!", holdDuration)
}
}
}()
The color and brightness of the pixel can also be changed:
shim.SetColor(255, 0, 0)
shim.SetBrightness(127)
Please refer to the godocs for full API reference.
Contributing
Contributions welcome! Please refer to the contributing guide.
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
Functions ¶
This section is empty.
Types ¶
type Driver ¶
type Driver struct {
// contains filtered or unexported fields
}
Driver is the primary struct for interacting with the Button SHIM device.
func New ¶
New returns a new Button SHIM hardware driver. The driver encapsulates a set of buttons and a single RGB LED, handling interaction with the actual device. Connects to the device on the given I2C bus at its standard address.
func NewWithConn ¶
NewWithConn returns a new Button SHIM hardware driver, using the given periph.io conn.Conn object. Typically New should be used instead, but this may be useful for testing using mocks, or a custom I2C connection with a different address than the default.
func (*Driver) ButtonPressChan ¶
ButtonPressChan returns a new receive channel that can be used to handle press events for a specific button. The actual message carries no payload - use it as a signalling mechanism only. For example:
pressA := shim.ButtonPressChan(buttonshim.ButtonA)
pressB := shim.ButtonPressChan(buttonshim.ButtonB)
go func() {
for {
select {
case <-pressA:
fmt.Println("Button A pressed!")
case <-pressB:
fmt.Println("Button B pressed!")
}
}
}()
func (*Driver) ButtonReleaseChan ¶
ButtonReleaseChan returns a new receive channel that can be used to handle release events for a specific button. The actual message indicates the final duration that the button was observed as being pressed for. The accuracy of this value is limited by the poll rate.
func (*Driver) SetBrightness ¶
SetBrightness sets the brightness of the pixel.
type Option ¶
type Option func(*options)
Option allows specifying behavior for the driver.
func WithButtonPollInterval ¶
WithButtonPollInterval allows modifying the button poll interval. A longer interval will use fewer system resources, but risks not registering a fast button press. Default 50ms.
Source Files