implemented dht11 sensor

README.md

@@ -1,6 +1,6 @@
 # pigpio-dht
 
-Dht22 control using node.js and pigpio.
+Dht sensor control using node.js and pigpio. Supported sensors are DHT11, DHT22 and AM2302.
 
 ## Installation
 
@@ -9,11 +9,24 @@ Dht22 control using node.js and pigpio.
 
 ## Usage
 
+```javascript
+const dht = require('dht');
+const sensor = dht(dataPin, dhtType);
+```
+
+| Sensor          | dhtType |
+|-----------------|:----------------:|
+| DHT11           | 11               |
+| DHT22 or AM2302 | 22               |
+
+### Example
+
 ```javascript
 const dht = require('dht');
 
 const dataPin = 5;
-const sensor = dht(dataPin);
+const dhtType = 22; //optional
+const sensor = dht(dataPin, dhtType);
 
 setInterval(() => { 
 	sensor.read();
@@ -29,22 +42,28 @@ sensor.on('badChecksum', () => {
 });
 ```
 
+### Methods
+#### `read()`
+
+Start a new reading of the sensor. This can't be called more then once every second for the DHT11 sensor or once every 2 seconds for the DHT22 sensor. 
+
 ### Events
 
-#### start
+#### `start`
 
 Emitted when starting to read a value.
 
-#### end
+#### `end`
 
-Emitted when the reading stops. This because it was complete, an error occured or anything else.
+Emitted when the reading stops. This because it was complete, an error occurred or anything else.
 
-#### result
+#### `result`
 
 - result object containing temperature and humidity
+
 Emitted when the reading was completed successful.
 
-#### badChecksum
+#### `badChecksum`
 
 Emitted when finished reading but the checksum was invalid.
 

index.js

@@ -17,6 +17,9 @@ module.exports = function(pin, type) {
 	var tempLow = 0;
 	var checksum = 0;
 
+	// default type is dht22
+	type = type || 22;
+
 	function startReading() {
 		if (dht.reading) {
 			// cancel out if we are already reading
@@ -50,6 +53,23 @@ module.exports = function(pin, type) {
 		dht.emit('end');
 	}
 
+	function interpretDht11() {
+		let rhum = rhumHigh;
+		let temp = tempHigh;
+
+		return { temperature: temp, humidity: rhum };
+	}
+	function interpretDht22() {
+		let rhum = ((rhumHigh << 8) + rhumLow) * 0.1;
+
+		// check the temperature sign
+		let mult = (tempHigh & 128) ? -0.1 : 0.1;
+		tempHigh = tempHigh & 127; // strip the sign bit
+		let temp = ((tempHigh << 8) + tempLow) * mult;
+
+		return { temperature: temp, humidity: rhum };
+	}
+
 	gpio.on('alert', (level, tick) => {
 		// Accumulate the 40 data bits.  Format into 5 bytes, humidity high,
 		// humidity low, temperature high, temperature low, checksum.
@@ -97,14 +117,9 @@ module.exports = function(pin, type) {
 
 					// Is checksum ok?
 					if ((total & 255) == checksum) {
-						let rhum = ((rhumHigh << 8) + rhumLow) * 0.1;
-
-						// check the temperature sign
-						let mult = (tempHigh & 128) ? -0.1 : 0.1;
-						tempHigh = tempHigh & 127; // strip the sign bit
-						let temp = ((tempHigh << 8) + tempLow) * mult;
+						let res = (type == 11) ? interpretDht11() ? interpretDht22();
 
-						dht.emit('result', { temperature: temp, humidity: rhum });
+						dht.emit('result', res);
 					} else {
 						dht.emit('badChecksum');
 					}