This revised client is a Netduino V2Plus/V3 Ethernet/V3 Wifi device with a Silicon Labs SI7005 temperature & humidity sensor. These devices when used as sensor nodes can be battery powered and I use the Mac Address as the unique device identifier.
In this version of the protocol the message type & device identifier are nibbles packed into the first bye of the message. This saved a byte but limits the number of message types and device identifier length
//---------------------------------------------------------------------------------
// Copyright (c) 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//---------------------------------------------------------------------------------
using System;
using System.Net;
using System.Text;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using Microsoft.SPOT.Net.NetworkInformation;
using devMobile.NetMF.Sensor;
using Gralin.NETMF.Nordic;
using SecretLabs.NETMF.Hardware.Netduino;
namespace devMobile.IoT.FIeldGateway.Netduino.Client
{
class Client
{
private const byte nRF24Channel = 10;
private const NRFDataRate nRF24DataRate = NRFDataRate.DR250kbps;
private readonly byte[] nRF24ClientAddress = Encoding.UTF8.GetBytes("T&H01");
private readonly byte[] nRF24BaseStationAddress = Encoding.UTF8.GetBytes("Base1");
private static byte[] deviceIdentifier;
private readonly OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);
private readonly NRF24L01Plus radio;
private readonly SiliconLabsSI7005 sensor = new SiliconLabsSI7005();
public Client()
{
radio = new NRF24L01Plus();
}
public void Run()
{
// Configure the nRF24 hardware
radio.OnDataReceived += OnReceive;
radio.OnTransmitFailed += OnSendFailure;
radio.OnTransmitSuccess += OnSendSuccess;
radio.Initialize(SPI.SPI_module.SPI1, Pins.GPIO_PIN_D7, Pins.GPIO_PIN_D3, Pins.GPIO_PIN_D2);
radio.Configure(nRF24ClientAddress, nRF24Channel, nRF24DataRate);
radio.Enable();
// Setup the device unique identifer, in this case the hardware MacAddress
deviceIdentifier = NetworkInterface.GetAllNetworkInterfaces()[0].PhysicalAddress;
Debug.Print(" Device Identifier : " + BytesToHexString(deviceIdentifier));
Timer humidityAndtemperatureUpdates = new Timer(HumidityAndTemperatureTimerProc, null, 15000, 15000);
Thread.Sleep(Timeout.Infinite);
}
private void HumidityAndTemperatureTimerProc(object state)
{
led.Write(true);
double humidity = sensor.Humidity();
double temperature = sensor.Temperature();
Debug.Print("H:" + humidity.ToString("F1") + " T:" + temperature.ToString("F1"));
string values = "T " + temperature.ToString("F1") + ",H " + humidity.ToString("F0");
// Stuff the single byte header ( payload type nibble & deviceIdentifierLength nibble ) + deviceIdentifier into first byte of payload
byte[] payload = new byte[ 1 + deviceIdentifier.Length + values.Length];
payload[0] = (byte)((1 << 4) | deviceIdentifier.Length );
Array.Copy(deviceIdentifier, 0, payload, 1, deviceIdentifier.Length);
Encoding.UTF8.GetBytes(values, 0, values.Length, payload, deviceIdentifier.Length + 1 );
radio.SendTo(nRF24BaseStationAddress, payload );
}
private void OnSendSuccess()
{
led.Write(false);
Debug.Print("Send Success!");
}
private void OnSendFailure()
{
Debug.Print("Send failed!");
}
private void OnReceive(byte[] data)
{
led.Write(!led.Read());
string message = new String(Encoding.UTF8.GetChars(data));
Debug.Print("Receive " + message); ;
}
private static string BytesToHexString(byte[] bytes)
{
string hexString = string.Empty;
// Create a character array for hexidecimal conversion.
const string hexChars = "0123456789ABCDEF";
// Loop through the bytes.
for (byte b = 0; b 0)
hexString += "-";
// Grab the top 4 bits and append the hex equivalent to the return string.
hexString += hexChars[bytes[b] >> 4];
// Mask off the upper 4 bits to get the rest of it.
hexString += hexChars[bytes[b] & 0x0F];
}
return hexString;
}
}
}
Bill of materials (prices as at March 2018)
-
- Netduino device USD – USD60-USD70
- Grove – Base shield V2 – USD8.90
- Grove – 5cm buckled cable – USD2.90
- Embedded coolness nRF24L01 Shield USD 10.40-USD17.85
Bill of materials (prices as at Jan 2018)