added mqtt sample

packages/net/src/mqtt.ts

@@ -557,16 +557,28 @@ export class MQTTClient {
             this.readyState = MQTTState.Connected
     }
 
-    // Publish a message
+    /**
+     * Attempts to publish a message on the MQTT stack
+     * @param topic topic of the message
+     * @param message payload as string, object that will be JSON serialized or buffer
+     * @param qos
+     * @param retained
+     * @returns
+     */
     public async publish(
         topic: string,
-        message?: string | Buffer,
+        message?: string | object | Buffer,
         qos: number = Constants.DefaultQos,
         retained: boolean = false
     ): Promise<boolean> {
-        const buf = typeof message === "string" ? Buffer.from(message) : message
-        message = null
         if (!(await this.canSend())) return false
+        const buf: Buffer =
+            typeof message === "string"
+                ? Buffer.from(message)
+                : message instanceof Buffer
+                ? message
+                : Buffer.from(JSON.stringify(message))
+        message = null
         const messageLen = buf ? buf.length : 0
         this.trace(`publish: ${topic} ${messageLen}b`)
         await this.send(createPublishHeader(topic, messageLen, qos, retained))

packages/runtime/src/schedule.ts

@@ -2,14 +2,15 @@ import { AsyncVoid } from "@devicescript/core"
 
 /**
  * Schedules a handler to be called at a later time. Executes timeout before interval if combined.
+ * If not specified, default to timeout 20ms and interval 60s.
  *
  * @param handler function to execute
  * @param options options to configure the scheduling
  * @returns clear timer function
  */
 export function schedule(
     handler: () => AsyncVoid,
-    options: {
+    options?: {
         /**
          * Time in milliseconds to wait before the first execution of the handler.
          */
@@ -30,8 +31,11 @@ export function schedule(
 
     if (!handler) return unsub
 
-    let { interval, timeout } = options
-    if (interval === undefined && timeout === undefined) timeout = 20
+    let { interval, timeout } = options || {}
+    if (interval === undefined && timeout === undefined) {
+        timeout = 20
+        interval = 60000
+    }
     if (timeout >= 0 && interval >= 0) {
         timerId = setTimeout(async () => {
             await handler()

packages/sampleprj/src/maintemperateshtc3.ts

@@ -0,0 +1,23 @@
+import "@dsboard/adafruit_qt_py_c3"
+import { deviceIdentifier } from "@devicescript/core"
+import { startMQTTClient } from "@devicescript/net"
+import { startSHTC3 } from "@devicescript/drivers"
+import { schedule } from "@devicescript/runtime"
+
+// mqtt settings
+const mqtt = await startMQTTClient({
+    host: "broker.hivemq.com",
+    proto: "tcp",
+    port: 1883,
+})
+const topic = `devs/temp/${deviceIdentifier("self")}`
+console.log({ topic })
+
+// sensors
+const { temperature } = await startSHTC3()
+// pushing temperature every minute
+schedule(async () => {
+    const t = await temperature.reading.read()
+    console.data({ t })
+    await mqtt.publish(topic, { t })
+})

website/docs/api/servers/aht20.mdx

@@ -13,7 +13,5 @@ Driver for AHT20 temperature/humidity sensor at I2C address `0x38`.
 import { startAHT20 } from "@devicescript/drivers"
 
 // highlight-next-line
-await startAHT20()
-const t = new ds.Temperature()
-const h = new ds.Humidity()
+const { temperature, humidity } = await startAHT20()
 ```

website/docs/samples/temperature-mqtt.mdx

@@ -0,0 +1,41 @@
+---
+sidebar_position: 2
+---
+
+# Temperature + MQTT
+
+This sample uses an ESP32-C3 board [Adafruit QT Py C3](/devices/esp32/adafruit-qt-py-c3)
+and a [SHTC3 sensor](/api/servers/shtc3) to publish a temperature reading to
+the [HiveMQ public MQTT broker](https://www.mqtt-dashboard.com/) every minute.
+
+```ts
+import "@dsboard/adafruit_qt_py_c3"
+import { deviceIdentifier } from "@devicescript/core"
+import { startMQTTClient } from "@devicescript/net"
+import { startSHTC3 } from "@devicescript/drivers"
+import { schedule } from "@devicescript/runtime"
+
+// mqtt settings
+const mqtt = await startMQTTClient({
+    host: "broker.hivemq.com",
+    proto: "tcp",
+    port: 1883,
+})
+const topic = `devs/temp/${deviceIdentifier("self")}`
+console.log({ topic })
+
+// sensors
+const { temperature } = await startSHTC3()
+// pushing temperature every minute
+schedule(async () => {
+    const t = await temperature.reading.read()
+    console.data({ t })
+    await mqtt.publish(topic, { t })
+})
+```
+
+:::warning
+
+This is a public MQTT broker, anyone can listen to the messages.
+
+:::