[clug] Raspberry Pi WLAN issues
Stephen.Gibson at anu.edu.au
Thu May 29 18:03:56 MDT 2014
Just a follow up on the sensors.
It turns out that the humidity-and-temperature sensor (dht11) uses a
(and voltage 3.3V (*)) to the temperature sensor (DS18B20).
The 1-wire DS18B20 interface is neat, connected to one Raspberry Pi GPIO
pin (and 5V, gnd),
with output via a kernel module:
dd 00 4b 46 7f ff 03 10 23 : crc=23 YES
dd 00 4b 46 7f ff 03 10 23 t=13812
(chilly at my place, but remember this 't' reading is not well calibrated)
Other 1-wire devices may be connected to the same wire.
The dht11 sensor is also connected to a single GPIO pin (and 3.3V, Gnd),
readings are obtained from a C-code program: Adafruit_DHT.c
Not as neat, as this interface is not a bus.
Just thought I would let you know before you bulk order any of the
(*) I also abused the dht11, with 5V, having assumed that it was another
1-wire bus device,
and simply swapping the wire connections from the DS20, before
checking the details.
Its output is now also uncalibrated. Fortunately, these sensors
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