read
wayland/dht20/read
Measure relative humidity and temperature.
read
@/read
Measure relative humidity and temperature.
DEV@/dht20-device
A dht20-device.
UPDpulse
Update. Triggers new read. Interval between pulses must be greater than 1 second.
Donepulse
Pulse on read.
Errorbyte
Error code: 00h=OK, 0Ah=ERROR_CHECKSUM, 0Bh=ERROR_CONNECT, 0Ch=MISSING_BYTES, 0Dh=ERROR_BYTES_ALL_ZERO,
0Eh=ERROR_READ_TIMEOUT,
0Fh=ERROR_LASTREAD.
Tempnumber
Temperature (°C).
RHnumber
Relative Humidity (%)
C++ implementation
#pragma XOD evaluate_on_pin disable
#pragma XOD evaluate_on_pin enable input_UPD
node {
void evaluate(Context ctx) {
// The node responds only if there is an input pulse
if (!isInputDirty<input_UPD>(ctx))
return;
auto sensor = getValue<input_DEV>(ctx);
int errorCode = sensor->read();
emitValue<output_Error>(ctx, abs(errorCode));
if (errorCode!=0) {
raiseError<output_RH>(ctx);
raiseError<output_Temp>(ctx);
raiseError<output_Done>(ctx);
} else {
emitValue<output_RH>(ctx, sensor->getHumidity());
emitValue<output_Temp>(ctx, sensor->getTemperature());
emitValue<output_Done>(ctx, 1);
}
}
}