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ObservAir
Operating Manual
3.6.
Computer (serial USB) connection
The ObservAir can stream data and receive commands via a USB serial
connection to a computer. While any serial monitor may be used to
communicate with the sensor, we recommend the free and open source
Arduino Serial Monitor for the basic operations outlined in this manual. A
dedicated computer interface is under development for the ObservAir, and
will be made available to all users at no cost.
3.6.1.
Connecting to Arduino Serial Monitor
Follow the steps outlined below to connect the ObservAir to the serial
monitor.
1.
The latest Arduino IDE can be downloaded and installed from
https://www.arduino.cc/en/main/software
2.
With the sensor turned on and operating normally without errors (LED
button is breathing slowly), connect the ObservAir to the computer
using the micro USB cable.
3.
Open the Arduino software and select the ObservAir’s serial port from
the “Tools” menu. For Mac OSX, the port is called
/dev/cu.usbserial-
DN43xxxx
, as shown in Figure 11 below. Windows does not use port
naming, and so the port must be found by process of elimination.
4.
In Arduino, open the “Serial Monitor” from the “Tools” menu.
5.
From the pulldown menus at the bottom of the Serial Monitor, select
the “Both NL & CR” and “115200 baud” settings (Figure 12).
6.
With the Serial Monitor configured, ObservAir data is displayed in real
time at the time interval set by the user. Commands can also be sent
to the sensor using the dialog box at the top of the Serial Monitor
window.
Figure 11.
Step 3: Select the ObservAir communications port in Arduino
(Mac OSX shown here).
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ObservAir
®
Operating Manual
Figure 12.
Step 5: Screenshot of the Arduino serial monitor. Select “Both
NL & CR” and “115200 baud” from the pull down menus, as shown. The
screenshot shows typical live data stream from the ObservAir.
3.6.2.
Serial data collection
Data can be aggregated through serial streaming, Serial data is streamed
in the same format as it is saved to the SD card (Section 3.5.1). Please note
that the Arduino Serial Monitor does not have data logging capability. Any
serial logging software can be configured to save ObservAir data using the
serial port settings in Table 6.
Port ID
DN43xxxx
Baud rate
115200
Data bits
8
Parity
None
Stop bits
1
Flow control
None
Table 6.
Serial port settings
3.6.3.
Sensor configuration: Serial commands
Commands can be sent over the Arduino Serial Monitor to configure the
ObservAir’s various operational settings. Most serial commands share the
same basic format:
$cmd$val
where ‘cmd’ is the name of command, and
‘val’ is the desired setting value. For example, the command ‘$setFR$100’
sets the sample flowrate to 100ccm. Table 6 documents all available
commands. All settings are saved to the SD card for each mission.