controller: mechanical relay implementation

andy-haynes · Apr 7, 2018 · 5c7ca1e · 5c7ca1e
1 parent 5ce1fa5
commit 5c7ca1e
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Showing 7 changed files with 108 additions and 7 deletions.
diff --git a/controller/config.ts b/controller/config.ts
@@ -2,6 +2,9 @@ export default {
   PID: {
     strikeThreshold: 0.95,  // percentage of target temp to reach before switching to PID control
   },
+  Relay: {
+    pins: [10, 12]
+  },
   thermometer: {
     defaultTemperature: -1, // uninitialized temperature value
     sampleIntervalMS: 750,  // ms between temperature measurements

diff --git a/controller/controller.ts b/controller/controller.ts
@@ -2,14 +2,14 @@ import BrewConfig from '../core/models/BrewConfig';
 import BrewStep from '../core/models/BrewStep';
 import BrewUpdate from '../core/models/BrewUpdate';
 import controllerConfig from './config';
-import { MockRelay } from './mocks';
 import { PIDController } from './pid';
 import { PiThermometer } from './thermometer';
+import { MechanicalRelay } from './relay';
 import { TemperatureUnits, ZynetMessageType} from '../core/constants';
 import ZynetConnection from './connection';
 import ZynetMessage from '../core/models/ZynetMessage';
 
-const relay = new MockRelay();
+const relay = new MechanicalRelay(controllerConfig.Relay.pins[0]);
 const thermometer = new PiThermometer();
 const mockUpdate = new BrewUpdate(1, 1, 60, 68, 152, false, 0);
 
@@ -35,10 +35,10 @@ function subscribeThermometer() {
     if (config) {
       if (pidThresholdReached) {
         pidController.updateTemperature(temperature);
-        relay.switch(pidController.state);
+        relay.toggle(pidController.state);
       } else {
         pidThresholdReached = temperature >= (config.steps[currentStepIndex].temperature * controllerConfig.PID.strikeThreshold);
-        relay.switch(!pidThresholdReached);
+        relay.toggle(!pidThresholdReached);
       }
     }
 

diff --git a/controller/interfaces.ts b/controller/interfaces.ts
@@ -11,7 +11,9 @@ export interface Connection {
 
 export interface Relay {
   on: boolean;
-  switch(on: boolean): void;
+  switchOn(): void;
+  switchOff(): void;
+  toggle(on: boolean): void;
 }
 
 export interface Thermometer {

diff --git a/controller/mocks.ts b/controller/mocks.ts
@@ -12,7 +12,9 @@ export class MockRelay implements Relay {
     this.on = false;
   }
 
-  switch(on: boolean): void { this.on = on; }
+  switchOn(): void { this.on = true; }
+  switchOff(): void { this.on = false; }
+  toggle(on: boolean): void { this.on = on; }
 }
 
 export class MockThermometer implements Thermometer {

diff --git a/controller/package-lock.json b/controller/package-lock.json
diff --git a/controller/package.json b/controller/package.json
@@ -10,6 +10,7 @@
   "license": "ISC",
   "dependencies": {
     "ds18b20": "^0.1.0",
-    "node-pid-controller": "^1.0.0"
+    "node-pid-controller": "^1.0.0",
+    "rpio": "^0.9.20"
   }
 }
diff --git a/controller/relay.ts b/controller/relay.ts
@@ -0,0 +1,74 @@
+import * as rpio from 'rpio';
+
+import config from './config';
+import { Relay } from './interfaces';
+
+
+export class MechanicalRelay implements Relay {
+  public on: boolean;
+
+  constructor(private pin: number) {
+    this.on = false;
+    rpio.open(this.pin, rpio.OUTPUT);
+  }
+
+  switchOn(): void {
+    this.toggle(true);
+  }
+
+  switchOff(): void {
+    this.toggle(false);
+  }
+
+  toggle(on: boolean): void {
+    rpio.write(this.pin, !on ? rpio.HIGH : rpio.LOW);
+    this.on = !on;
+  }
+}
+
+// in order to spread out the wear on the mechanical relays, keep
+// a pointer to the current relay and only turn it on when a relay
+// needs is activated
+// on the next activation increment the relay pointer
+export class RelayArray implements Relay  {
+  private currentRelayIndex: number;
+  private relays: Relay[];
+
+  constructor(private reversed = true) {
+    this.currentRelayIndex = 0;
+    this.relays = config.Relay.pins.map(pin => new MechanicalRelay(pin));
+  }
+
+  public get on(): boolean {
+    return this.currentRelay.on;
+  }
+
+  private get currentRelay(): Relay {
+    return this.relays[this.currentRelayIndex];
+  }
+
+  switchOn(): void {
+    // check that the current relay is not already switched on
+    if (!this.currentRelay.on) {
+      // increment the relay pointer
+      this.currentRelayIndex = (this.currentRelayIndex + 1) % this.relays.length;
+      // switch on the current relay
+      this.currentRelay.switchOn();
+    }
+  }
+
+  switchOff(): void {
+    // turn off any relays that are on
+    this.relays
+      .filter(relay => relay.on)
+      .forEach(relay => relay.switchOff());
+  }
+
+  toggle(on: boolean): void {
+    if (!(on && this.reversed)) {
+      this.switchOn();
+    } else {
+      this.switchOff();
+    }
+  }
+}