/// <summary>
/// Make a temperature and humidity reading.
/// </summary>
public void Update()
{
_si7021.WriteByte(Registers.MeasureHumidityNoHold);
//
// Maximum conversion time is 12ms (page 5 of the datasheet).
//
Thread.Sleep(25);
var data = _si7021.ReadBytes(3);
var humidityReading = (ushort)((data[0] << 8) + data[1]);
Humidity = ((125 * (float)humidityReading) / 65536) - 6;
if (Humidity < 0)
{
Humidity = 0;
}
else
{
if (Humidity > 100)
{
Humidity = 100;
}
}
data = _si7021.ReadRegisters(Registers.ReadPreviousTemperatureMeasurement, 2);
var temperatureReading = (short)((data[0] << 8) + data[1]);
Temperature = (float)(((175.72 * temperatureReading) / 65536) - 46.85);
}
public static void Main()
{
// setup some configs
ushort speed = 100;
ushort timeout = 100;
ushort numberOfDevices = 0;
// loop forever
while (true)
{
numberOfDevices = 0;
// loop through all the possible I2C addresses (0-127)
for (byte i = 0; i < 127; i++)
{
I2CBus i2C = new I2CBus(i, speed, timeout);
try
{
i2C.WriteByte(0);
Debug.Print("Found I2C device at: " + i.ToString("X"));
numberOfDevices++;
}
catch (Exception e) { }
}
if (numberOfDevices == 0)
{
Debug.Print("No I2C devices found.");
}
// wait five seconds before scanning again.
Thread.Sleep(5000);
}
}
private void scanBusAddresses()
{
Debug.Print(MethodNames.SCAN_BUS_ADDRESSES);
if (loadAddressWhitelist())
{
Debug.Print(LogMessages.LOADED_WHITELIST);
return;
}
ushort speed = 100;
ushort timeout = 200;
for (byte i = SLAVE_SCAN_LOW; i < SLAVE_SCAN_HIGH; i++)
{
I2CBus i2C = new I2CBus(i, speed, timeout);
try
{
i2C.WriteByte(0);
var slaveAddressOnly = new Slave {
address = i, clock_stretch = 40000, name = "not_assigned", role = Role.UNDEFINED
};
_assimSlaves.Add(slaveAddressOnly);
}
catch { }
}
if (_assimSlaves.Count == 0)
{
//Debug.Print("No I2C devices found.");
}
else
{
//Debug.Print(_numberOfDevices.ToString() + " I2C devices found.");
}
}
public double GetPressure()
{
double current_temperature = GetTemperature();
byte[] bytes = new byte[] { 0xF4, (byte)(0x34 + (3 << 6)) };
bus.WriteBytes(deviceID, bytes);
System.Threading.Thread.Sleep(28);
bus.WriteByte(deviceID, (byte)0xF6);
byte ms = bus.ReadBytes(deviceID, 1)[0];
bus.WriteByte(deviceID, (byte)0xF7);
byte ls = bus.ReadBytes(deviceID, 1)[0];
bus.WriteByte(deviceID, (byte)0xF8);
byte xs = bus.ReadBytes(deviceID, 1)[0];
double pu = (ms * 256.0) + ls + (xs / 256.0);
double s, x, y, z;
double x0 = AC1;
double x1 = 160.0 * Math.Pow(2, -13) * AC2;
double x2 = Math.Pow(160, 2) * Math.Pow(2, -25) * B2;
double c3 = 160.0 * Math.Pow(2, -15) * AC3;
double c4 = Math.Pow(10, -3) * Math.Pow(2, -15) * AC4;
double b1 = Math.Pow(160, 2) * Math.Pow(2, -30) * B1;
double y0 = c4 * Math.Pow(2, 15);
double y1 = c4 * c3;
double y2 = c4 * b1;
double p0 = (3791.0 - 8.0) / 1600.0;
double p1 = 1.0 - 7357.0 * Math.Pow(2, -20);
double p2 = 3038.0 * 100.0 * Math.Pow(2, -36);
s = current_temperature - 25.0;
x = (x2 * Math.Pow(s, 2)) + (x1 * s) + x0;
y = (y2 * Math.Pow(s, 2)) + (y1 * s) + y0;
z = (pu - x) / y;
double P = (p2 * Math.Pow(z, 2)) + (p1 * z) + p0;
return(P);
}
/// <summary>
/// Get metadata from slaves, store in _assimSlaves and JSON files
/// </summary>
public void getMetadata()
{
Debug.Print(MethodNames.GET_METADATA);
bool i2cNodeProcessed;
string name = "", value = "";
ushort speed = 200; // 1000 breaks ReadBytes
ushort timeout = 200;
foreach (Slave slave in _assimSlaves)
{
byte slaveAddress = slave.address;
Hashtable rootPairs = new Hashtable();
ArrayList userMetas = Config.deserializeUserMetas(slaveAddress);
I2CBus i2C = new I2CBus(slaveAddress, speed, timeout);
while (true)
{
i2cNodeProcessed = false;
for (byte segment = 0; segment < 3; segment++) // 3 requests per meta
{
try {
var byteArray = i2C.ReadBytes(16);
var packet = getPacketFromBytes(byteArray);
switch (segment)
{
case 0:
name = packet;
break;
case 1:
if (name == packet)
{ // this is the main symptom of message sequence is out of sync - not experienced on Netduino node
Debug.Print(LogMessages.OUT_OF_SYNC);
Debug.Print(LogMessages.RESTARTING);
// ToDo: restart the device
}
value = packet;
getUserMetaOrDefault(userMetas, name, ref value);
setMetaOfInterest(slave, rootPairs, name, value);
break;
case 2:
Debug.Print(name + (name.Length > 6 ? LogMessages.TAB_1 : LogMessages.TAB_2) + value);
// check if last metadata
if (packet == I2cMessages.SEG3_DISCONTINUE) // 0 on last property
{
i2cNodeProcessed = true;
break;
}
break;
default:
break;
}
} catch (Exception ex) {
Debug.Print(ex.InnerException.Message);
return;
}
}// end for segment
if (i2cNodeProcessed) // break out if last metadata
{
break;
}
}// end while true
Debug.Print(LogMessages.CONFIRM_METADATA + slave.name);
i2C.WriteByte(I2cMessages.WRITE_CONFIRM_METADATA);
// SAVE /config/metadata/<i>.json
if (!Config.serializeSlaveMetas(slaveAddress, rootPairs))
{
Debug.Print(LogMessages.ERROR_SAVING_FILE + slaveAddress.ToString());
}
}// end foreach slave
}
