traffic light server (#574)

Author: pelikhan

Diff for: packages/drivers/src/index.ts

@@ -13,5 +13,6 @@ export * from "./indexedscreen"
 export * from "./dotmatrix"
 export * from "./st7735"
 export * from "./uc8151"
+export * from "./trafficlight"
 
 configureHardware({ scanI2C: false })

Diff for: packages/drivers/src/trafficlight.ts

@@ -0,0 +1,58 @@
+import * as ds from "@devicescript/core"
+import { AsyncValue, GPIOMode, OutputPin, TrafficLightServerSpec } from "@devicescript/core";
+import { Server, ServerOptions, startServer } from "@devicescript/server";
+
+export interface TrafficLightOptions extends ServerOptions {
+    red: OutputPin,
+    yellow: OutputPin,
+    green: OutputPin
+}
+
+class TrafficLightServer extends Server implements TrafficLightServerSpec {
+    private lights: { pin: OutputPin, state: boolean }[] = []
+
+    constructor(options: TrafficLightOptions) {
+        super(ds.TrafficLight.spec, options)
+        this.lights = [
+            {pin: options.red, state: false},
+            {pin: options.yellow, state: false},
+            {pin: options.green, state: false}
+        ]
+        for(const light of this.lights) {
+            light.pin?.setMode(GPIOMode.Output)
+            light.pin?.write(light.state)
+        }
+    }
+
+    private setState(index: number, value: boolean) {
+        this.lights[index].state = !!value
+        this.lights[index].pin?.write(this.lights[index].state)
+    }
+
+    red(): AsyncValue<boolean> {
+        return this.lights[0].state
+    }
+    set_red(value: boolean): AsyncValue<void> {
+        return this.setState(0, value)
+    }
+    yellow(): AsyncValue<boolean> {
+        return this.lights[1].state
+    }
+    set_yellow(value: boolean): AsyncValue<void> {
+        return this.setState(1, value)   
+     }
+    green(): AsyncValue<boolean> {
+        return this.lights[2].state
+    }
+    set_green(value: boolean): AsyncValue<void> {
+        return this.setState(2, value)   
+    }
+}
+
+/**
+ * Starts a traffic light driver over 3 output pins
+ */
+export async function startTrafficLight(options: TrafficLightOptions & ServerOptions) {
+    const server = new TrafficLightServer(options)
+    return new ds.TrafficLight(startServer(server))
+}

Diff for: packages/sampleprj/src/maintrafficlight.ts

@@ -1,7 +1,13 @@
-import { Temperature, TrafficLight } from "@devicescript/core"
+import { pins } from "@dsboard/pico_w"
+import { Temperature } from "@devicescript/core"
+import { startTrafficLight } from "@devicescript/drivers"
 
 const temp = new Temperature()
-const light = new TrafficLight()
+const light = await startTrafficLight({
+    red: pins.GP10,
+    yellow: pins.GP11,
+    green: pins.GP12,
+})
 temp.reading.subscribe(async t => {
     if (t > 30) {
         await light.green.write(false)
@@ -15,5 +21,5 @@ temp.reading.subscribe(async t => {
         await light.green.write(true)
         await light.yellow.write(false)
         await light.red.write(false)
-        }
+    }
 })

Diff for: website/docs/api/drivers/trafficlight.md

@@ -0,0 +1,18 @@
+# Traffic Light
+
+The traffic light driver, `startTrafficLight` is used to control a toy traffic light, driving 3 LEDs.
+
+```ts
+import { pins } from "@dsboard/pico_w"
+import { startTrafficLight } from "@devicescript/drivers"
+
+const light = await startTrafficLight({
+    red: pins.GP10,
+    yellow: pins.GP11,
+    green: pins.GP12,
+})
+
+await light.green.write(true)
+await light.yellow.write(false)
+await light.red.write(false)
+```