Support for UART control mode for a02yyuw distance sensor

Source/Meadow.Foundation.Peripherals/Sensors.Distance.A02yyuw/Driver/A02yyuw.cs

@@ -12,6 +12,15 @@ namespace Meadow.Foundation.Sensors.Distance
     /// </summary>
     public class A02yyuw : PollingSensorBase<Length>, IRangeFinder, ISleepAwarePeripheral, IDisposable
     {
+
+        /// <summary>
+        /// Constant for output mode UART Auto
+        /// </summary>
+        public const byte MODE_UART_AUTO = 1;
+        /// <summary>
+        /// Constant for output mode UART Control
+        /// </summary>
+        public const byte MODE_UART_CONTROL = 1;
         /// <summary>
         /// Distance from sensor to object
         /// </summary>
@@ -37,6 +46,11 @@ public class A02yyuw : PollingSensorBase<Length>, IRangeFinder, ISleepAwarePerip
         int serialDataBytesRead = 0;
         byte serialDataFirstByte;
 
+        // Output buffer
+        private byte[] sendBufer = { 0 };
+
+        private byte outPutMode;
+
         private TaskCompletionSource<Length>? dataReceivedTaskCompletionSource;
 
         private readonly bool createdPort = false;
@@ -48,8 +62,9 @@ public class A02yyuw : PollingSensorBase<Length>, IRangeFinder, ISleepAwarePerip
         /// </summary>
         /// <param name="device">The device connected to the sensor</param>
         /// <param name="serialPortName">The serial port</param>
-        public A02yyuw(IMeadowDevice device, SerialPortName serialPortName)
-            : this(device.CreateSerialPort(serialPortName, portSpeed))
+        /// <param name="outPutModeParam">Output mode of the distance sensor, default is AUTO</param>
+        public A02yyuw(IMeadowDevice device, SerialPortName serialPortName, byte outPutModeParam = MODE_UART_AUTO)
+            : this(device.CreateSerialPort(serialPortName, portSpeed, outPutModeParam))
         {
             createdPort = true;
         }
@@ -58,11 +73,14 @@ public A02yyuw(IMeadowDevice device, SerialPortName serialPortName)
         /// Creates a new A02YYUW object communicating over serial
         /// </summary>
         /// <param name="serialMessage">The serial message port</param>
-        public A02yyuw(ISerialPort serialMessage)
+        /// <param name="outPutModeParam">Output mode of the distance sensor, default is AUTO</param>
+
+        public A02yyuw(ISerialPort serialMessage, byte outPutModeParam = MODE_UART_AUTO)
         {
             serialPort = serialMessage;
             serialPort.ReadTimeout = TimeSpan.FromSeconds(5);
             serialPort.DataReceived += SerialPortDataReceived;
+            outPutMode = outPutModeParam;
         }
 
         /// <summary>
@@ -125,7 +143,11 @@ private async Task<Length> ReadSingleValue()
             {
                 serialPort.Open();
             }
-
+            // in UART Control Mode, send a 0 value over serial to toggle the control line
+            if (outPutMode == MODE_UART_CONTROL)
+            {
+                serialPort.Write(sendBufer);
+            }
             var timeOutTask = Task.Delay(SensorReadTimeOut);
 
             await Task.WhenAny(dataReceivedTaskCompletionSource.Task, timeOutTask);

Source/Meadow.Foundation.Peripherals/Sensors.Distance.A02yyuw/Driver/Readme.md

@@ -2,19 +2,31 @@
 
 **A02yyuw serial ultrasonic distance sensor**
 
-The **A02yyuw** library is included in the **Meadow.Foundation.Sensors.Distance.A02yyuw** nuget package and is designed for the [Wilderness Labs](www.wildernesslabs.co) Meadow .NET IoT platform.
+### Pinout for Sensor:
+1. (red) VCC power input 3- 5 V
+2. (black) ground
+3. (yellow) Rx pin function depends on output mode
+4. (white) Tx pin function depends on output mode
 
-This driver is part of the [Meadow.Foundation](https://developer.wildernesslabs.co/Meadow/Meadow.Foundation/) peripherals library, an open-source repository of drivers and libraries that streamline and simplify adding hardware to your C# .NET Meadow IoT applications.
+The A02 series supports 5 different modes of operation (PWM output, UART Controlled output,UART Auto output, Switched output).
+The Rx and Tx pin function corresponds to the output mode selected before ordering, and can not be changed. The **A02yyuw** library supports the 
+UART Controlled output and UART Auto output of the A02, which can be selected in software.
 
-For more information on developing for Meadow, visit [developer.wildernesslabs.co](http://developer.wildernesslabs.co/).
+In UART Auto mode, when the Rx pin is held low, the module outputs real-time values on the Tx pin with a response time of 100ms.
+When pin(RX)is held high, the module outputs processed values, and the data is more stable. The response time is 100~500ms. The **A02yyuw** library
+keeps Rx high in UART Auto output, so processed values are obtained.
 
-To view all Wilderness Labs open-source projects, including samples, visit [github.com/wildernesslabs](https://github.com/wildernesslabs/).
+In UART Controlled mode, the module wil perform a distance detection and send data on the Tx pin after the Rx pin receives a falling edge pulse.
+The period between Rx pulses must be greater than 70ms. The **A02yyuw** library sends a pulse by writing a byte of data to the serial port.
+
+The **A02yyuw** library is designed for the [Wilderness Labs](www.wildernesslabs.co) Meadow .NET IoT platform and is part of [Meadow.Foundation](https://developer.wildernesslabs.co/Meadow/Meadow.Foundation/).
+
+The **Meadow.Foundation** peripherals library is an open-source repository of drivers and libraries that streamline and simplify adding hardware to your C# .NET Meadow IoT application.
 
-## Installation
+For more information on developing for Meadow, visit [developer.wildernesslabs.co](http://developer.wildernesslabs.co/).
 
-You can install the library from within Visual studio using the the NuGet Package Manager or from the command line using the .NET CLI:
+To view all Wilderness Labs open-source projects, including samples, visit [github.com/wildernesslabs](https://github.com/wildernesslabs/).
 
-`dotnet add package Meadow.Foundation.Sensors.Distance.A02yyuw`
 ## Usage
 
 ```csharp
@@ -73,20 +85,3 @@ private void A02yyuw_DistanceUpdated(object sender, IChangeResult<Length> e)
 ## Need Help?
 
 If you have questions or need assistance, please join the Wilderness Labs [community on Slack](http://slackinvite.wildernesslabs.co/).
-## About Meadow
-
-Meadow is a complete, IoT platform with defense-grade security that runs full .NET applications on embeddable microcontrollers and Linux single-board computers including Raspberry Pi and NVIDIA Jetson.
-
-### Build
-
-Use the full .NET platform and tooling such as Visual Studio and plug-and-play hardware drivers to painlessly build IoT solutions.
-
-### Connect
-
-Utilize native support for WiFi, Ethernet, and Cellular connectivity to send sensor data to the Cloud and remotely control your peripherals.
-
-### Deploy
-
-Instantly deploy and manage your fleet in the cloud for OtA, health-monitoring, logs, command + control, and enterprise backend integrations.
-
-

Source/Meadow.Foundation.Peripherals/Sensors.Distance.A02yyuw/Samples/A02yyuw_Sample/MeadowApp.cs

@@ -1,4 +1,6 @@
-using Meadow;
+//#define DEVICE_FEATHER
+#define DEVICE_PROJECT_LAB
+using Meadow;
 using Meadow.Devices;
 using Meadow.Foundation.Sensors.Distance;
 using Meadow.Units;
@@ -8,7 +10,12 @@
 namespace A02yyuw_Sample
 {
     // Change F7FeatherV2 to F7FeatherV1 for V1.x boards
+#if DEVICE_FEATHER          // Feather: Change F7FeatherV2 to F7FeatherV1 for V1.x boards
+    public class MeadowApp : App<F7FeatherV2>
+#endif
+#if DEVICE_PROJECT_LAB      //ProjectLab: uses an F7CoreComputeV2 board
     public class MeadowApp : App<F7CoreComputeV2>
+#endif
     {
         //<!=SNIP=>
 
@@ -18,7 +25,7 @@ public override Task Initialize()
         {
             Resolver.Log.Info("Initialize...");
 
-            a02yyuw = new A02yyuw(Device, Device.PlatformOS.GetSerialPortName("COM4"));
+            a02yyuw = new A02yyuw(Device, Device.PlatformOS.GetSerialPortName("COM4"), A02yyuw.MODE_UART_CONTROL);
 
             var consumer = A02yyuw.CreateObserver(
                 handler: result =>