examples: add Find My Gopherbot example

Signed-off-by: deadprogram <[email protected]>

Author: deadprogram

examples/findmy/README.md

@@ -0,0 +1,13 @@
+# Find My Gopherbot
+
+Your Gopherbot is now a FindMy beacon.
+
+Requires CircuitPlayground Bluefruit.
+
+Uses "Go Haystack" see [https://github.com/hybridgroup/go-haystack](https://github.com/hybridgroup/go-haystack)
+
+## Flashing
+
+```shell
+tinygo flash -target circuitplay-bluefruit -ldflags="-X main.AdvertisingKey='YOURKEYHERE'" ./examples/demo
+```

examples/findmy/beacon.go

@@ -0,0 +1,74 @@
+//go:build circuitplay_bluefruit
+
+package main
+
+import (
+	"encoding/base64"
+	"errors"
+	"time"
+
+	"github.com/hybridgroup/go-haystack/lib/findmy"
+	"tinygo.org/x/bluetooth"
+)
+
+var adapter = bluetooth.DefaultAdapter
+
+// AdvertisingKey is the public key of the device. Must be base64 encoded.
+var AdvertisingKey string
+
+func initBeacon() {
+	// wait for USB serial to be available
+	time.Sleep(2 * time.Second)
+
+	key, err := getKeyData()
+	if err != nil {
+		fail("failed to get key data: " + err.Error())
+	}
+	println("key is", AdvertisingKey, "(", len(key), "bytes)")
+
+	opts := bluetooth.AdvertisementOptions{
+		AdvertisementType: bluetooth.AdvertisingTypeNonConnInd,
+		Interval:          bluetooth.NewDuration(1285000 * time.Microsecond), // 1285ms
+		ManufacturerData:  []bluetooth.ManufacturerDataElement{findmy.NewData(key)},
+	}
+
+	must("enable BLE stack", adapter.Enable())
+
+	// Set the address to the first 6 bytes of the public key.
+	adapter.SetRandomAddress(bluetooth.MAC{key[5], key[4], key[3], key[2], key[1], key[0] | 0xC0})
+
+	println("configure advertising...")
+	adv := adapter.DefaultAdvertisement()
+	must("config adv", adv.Configure(opts))
+
+	println("start advertising...")
+	must("start adv", adv.Start())
+}
+
+// getKeyData returns the public key data from the base64 encoded string.
+func getKeyData() ([]byte, error) {
+	val, err := base64.StdEncoding.DecodeString(AdvertisingKey)
+	if err != nil {
+		return nil, err
+	}
+	if len(val) != 28 {
+		return nil, errors.New("public key must be 28 bytes long")
+	}
+
+	return val, nil
+}
+
+// must calls a function and fails if an error occurs.
+func must(action string, err error) {
+	if err != nil {
+		fail("failed to " + action + ": " + err.Error())
+	}
+}
+
+// fail prints a message over and over forever.
+func fail(msg string) {
+	for {
+		println(msg)
+		time.Sleep(time.Second)
+	}
+}

examples/findmy/main.go

@@ -0,0 +1,135 @@
+package main
+
+import (
+	"image/color"
+	"time"
+
+	"github.com/hybridgroup/gopherbot"
+)
+
+const (
+	greenVisor = iota
+	redVisor
+	cylonVisor
+	tiltVisor
+	xmasVisor
+)
+
+const (
+	forward = iota
+	backward
+)
+
+var (
+	accel   *gopherbot.AccelerometerDevice
+	visor   *gopherbot.VisorDevice
+	speaker *gopherbot.SpeakerDevice
+
+	pos = 0
+)
+
+func main() {
+	initBeacon()
+
+	accel = gopherbot.Accelerometer()
+	visor = gopherbot.Visor()
+	speaker = gopherbot.Speaker()
+
+	antenna := gopherbot.Antenna()
+	backpack := gopherbot.Backpack()
+
+	left := gopherbot.LeftButton()
+	right := gopherbot.RightButton()
+
+	mode := redVisor
+
+	go antenna.Blink()
+
+	for {
+		if right.Pushed() {
+			mode++
+			if mode > xmasVisor {
+				mode = greenVisor
+			}
+		}
+
+		if left.Pushed() {
+			mode--
+			if mode < greenVisor {
+				mode = xmasVisor
+			}
+		}
+
+		switch mode {
+		case greenVisor:
+			visor.Green()
+			if gopherbot.Slider().IsOn() {
+				backpack.Alternate(color.RGBA{R: 0x00, G: 0xff, B: 0x00}, color.RGBA{R: 0x00, G: 0x00, B: 0xff})
+			} else {
+				backpack.Off()
+			}
+		case redVisor:
+			visor.Red()
+			if gopherbot.Slider().IsOn() {
+				backpack.Red()
+			} else {
+				backpack.Off()
+			}
+		case cylonVisor:
+			visor.Cylon()
+			if gopherbot.Slider().IsOn() {
+				backpack.Alternate(color.RGBA{R: 0xff, G: 0x00, B: 0x00}, color.RGBA{R: 0x00, G: 0x00, B: 0x00})
+			} else {
+				backpack.Off()
+			}
+		case tiltVisor:
+			tilt()
+		case xmasVisor:
+			visor.Xmas()
+			if gopherbot.Slider().IsOn() {
+				backpack.Xmas()
+			} else {
+				backpack.Off()
+			}
+		}
+
+		time.Sleep(200 * time.Millisecond)
+	}
+}
+
+func tilt() {
+	x, y, z, _ := accel.ReadAcceleration()
+	println(x, y, z)
+
+	switch {
+	case x < 300000 && x > -300000:
+		switch {
+		case pos <= gopherbot.VisorLEDCount/2-1:
+			pos++
+		case pos >= gopherbot.VisorLEDCount/2+1:
+			pos--
+		}
+	case x > 300000:
+		pos++
+		if pos == gopherbot.VisorLEDCount {
+			pos = gopherbot.VisorLEDCount - 1
+			speaker.Bleep()
+		}
+	case x < -300000:
+		pos--
+		if pos < 0 {
+			pos = 0
+			speaker.Bleep()
+		}
+	}
+
+	for i := range visor.LED {
+		if i == pos {
+			visor.LED[i] = color.RGBA{R: 0x00, G: 0xff, B: 0x00, A: 0x77}
+		} else {
+			visor.LED[i] = color.RGBA{R: 0x00, G: 0x00, B: 0x00, A: 0x77}
+		}
+	}
+
+	visor.Show()
+}