Notes on temp probe
Jim's Arduino-based hardware
Arduino Model: MKRZERO
To use on Linux, install Arduino IDE. Next go to Tools > Board: <some-model-name> > Boards Manager...
In the Boards Manager, filter by MKRZERO, and install the Arduino SAMD Board drivers.
Finally, ensure your user is part of the `uucp` and `dialout` groups via
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sudo usermod -a -G dialout -G uucp <user> |
If you are unsure what the pointer to the device is, run
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sudo dmesg --follow -T |
and unplug/plug the device. It should be something like
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/dev/ttyACM0 |
Finally, whenever you plug/unplug the device and get `Permission Denied` errors, add rw permissions to the file
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sudo chmod a+rw /dev/ttyACM0 |
Hardware
235-165-ND: FP 07 FAST TIP PROBE, 150 Kohm, at 25C
AAS-920-267D-Thermometrics-NTC-TypeFP07-041216-web.pdf
self-heating is 1C per 50 uW of power dissipation. Resistance is 150K at room temperature. Still-air thermal time constant is 100 msec.
plot of temperature increase vs. applied voltage across thermistor:
The problem with self-heating is that we are increasingly sensitive to local windspeed rather than temperature. We definitely don't want to exceed one volt across one thermistor, or 2 volts across both of them.
Paper on thermal time constant measurements in still and moving air: [15200426 - Journal of Atmospheric and Oceanic Technology] Time Constant Estimates for Radiosonde Temperature Sensors.pdf
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Statement of Temperature Probe Purpose:
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High Level Project Description:
Here is a picture of the temperature array, taken in the Harvard lab on 05/02/2022, followed by a high-level description of its operation: 
The temperature array consists of three orthogonal 1 meter axes of PVC pipe, raised 1 meter off the ground. Running along each axis is a thermistor-thermistor pair, forming a voltage divider. For each pair, one of the thermistors is mounted at the vertex of the three axes (circled in blue above), and the other is at the end of the axis (circled in red above). The voltage between the two thermistors (the output voltage of the voltage divider) is read out. The supply voltages are provided and the output voltages are measured from an electronics control box at the foot of the temperature array (boxed in green above). Together, these three axes provide measurements of thermal variations with mK prevision.
An external control computer directs the Arduino ADU that provides the source voltage and digitizes the output voltage at 1kHz.
See the pages below for further details. In particular, to see how to run the Temp Probe at AuxTel, see the Operating at AuxTel page. To see how to consolidate a night of data into a usable single data file of temperature variances, see the Analyzing Data page.
Experiment Details:
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