espat: add example that uses MQTT publish to open server

Signed-off-by: Ron Evans <ron@hybridgroup.com>
2026-08-05 07:27:49 +00:00 · 2019-06-21 10:58:19 +02:00
parent 9c88d1fab4
commit 1d9e393948
1 changed files with 148 additions and 0 deletions
@@ -0,0 +1,148 @@
+// This is a sensor station that uses a ESP8266 or ESP32 running on the device UART1.
+// It creates an MQTT connection that publishes a message every second
+// to an MQTT broker.
+//
+// In other words:
+// Your computer <--> UART0 <--> MCU <--> UART1 <--> ESP8266 <--> Internet <--> MQTT broker.
+//
+// You must install the Paho MQTT package to build this program:
+//
+// 		go get github.com/eclipse/paho.mqtt.golang
+//
+package main
+
+import (
+	"machine"
+	"time"
+
+	"github.com/eclipse/paho.mqtt.golang/packets"
+	"tinygo.org/x/drivers/espat"
+)
+
+// access point info
+const ssid = "YOURSSID"
+const pass = "YOURPASS"
+
+// IP address of the MQTT broker to use. Replace with your own info.
+const server = "test.mosquitto.org:1883"
+
+// change these to connect to a different UART or pins for the ESP8266/ESP32
+var (
+	uart = machine.UART1
+	tx   = machine.D10
+	rx   = machine.D11
+
+	console = machine.UART0
+
+	adaptor *espat.Device
+	conn    *espat.TCPSerialConn
+	err     error
+	mid     uint16
+)
+
+func main() {
+	uart.Configure(machine.UARTConfig{TX: tx, RX: rx})
+
+	time.Sleep(3000 * time.Millisecond)
+
+	// Init esp8266/esp32
+	adaptor = espat.New(uart)
+	adaptor.Configure()
+
+	// first check if connected
+	if adaptor.Connected() {
+		console.Write([]byte("Connected to wifi adaptor.\r\n"))
+		adaptor.Echo(false)
+
+		connectToAP()
+	} else {
+		console.Write([]byte("\r\n"))
+		console.Write([]byte("Unable to connect to wifi adaptor.\r\n"))
+		return
+	}
+
+	// now make TCP connection
+	raddr, _ := adaptor.ResolveTCPAddr("tcp", server)
+	if raddr != nil {
+		println("The IP address from DNS lookup is:")
+		println(string(raddr.IP))
+		println(raddr.Port)
+	}
+	laddr := &espat.TCPAddr{Port: 1883}
+
+	console.Write([]byte("Dialing TCP connection...\r\n"))
+	conn, err = adaptor.DialTCP("tcp", laddr, raddr)
+	if err != nil {
+		println("tcp connect error")
+		println(err.Error())
+	}
+
+	err = connectToMQTTServer()
+
+	for {
+		console.Write([]byte("Publishing MQTT packets...\r\n"))
+
+		publish := packets.NewControlPacket(packets.Publish).(*packets.PublishPacket)
+		publish.Qos = 0
+		publish.TopicName = "tinygo"
+		publish.Payload = []byte("Hello, mqtt\r\n")
+		publish.MessageID = mid
+		mid++
+
+		publish.Write(conn)
+
+		time.Sleep(1000 * time.Millisecond)
+	}
+
+	// Right now this code is never reached. Need a way to trigger it...
+	console.Write([]byte("Disconnecting TCP...\r\n"))
+	conn.Close()
+	console.Write([]byte("Done.\r\n"))
+}
+
+// connect to access point
+func connectToAP() {
+	console.Write([]byte("Connecting to wifi network...\r\n"))
+	adaptor.SetWifiMode(espat.WifiModeClient)
+	adaptor.ConnectToAP(ssid, pass, 10)
+	console.Write([]byte("Connected.\r\n"))
+	console.Write([]byte(adaptor.GetClientIP()))
+	console.Write([]byte("\r\n"))
+}
+
+func connectToMQTTServer() error {
+	// send the MQTT connect message
+	connectPkt := packets.NewControlPacket(packets.Connect).(*packets.ConnectPacket)
+	connectPkt.Qos = 0
+	// connectPkt.Username = "tinygo"
+	// connectPkt.Password = []byte("1234")
+	connectPkt.ClientIdentifier = "tinygo-client"
+	connectPkt.ProtocolVersion = 4
+	connectPkt.ProtocolName = "MQTT"
+	connectPkt.Keepalive = 30
+
+	console.Write([]byte("Sending MQTT connect...\r\n"))
+	err := connectPkt.Write(conn)
+	if err != nil {
+		println("mqtt connect error")
+		println(err.Error())
+		return err
+	}
+
+	console.Write([]byte("Waiting for MQTT connect...\r\n"))
+	// TODO: handle timeout
+	for {
+		packet, _ := packets.ReadPacket(conn)
+
+		if packet != nil {
+			_, ok := packet.(*packets.ConnackPacket)
+			if ok {
+				console.Write([]byte("Connected to MQTT server.\r\n"))
+				println(packet.String())
+				return nil
+			}
+		}
+
+		time.Sleep(100 * time.Millisecond)
+	}
+}