[PLUG] Temperature and Raspberry Pi.

Tue Jan 17 16:59:16 UTC 2017

Stratification occurs rapidly if you don't have your ice at all levels of
your container.  Ice floats, warmer water sinks.

On Tue, Jan 17, 2017 at 3:15 AM, Tom <tomas.kuchta.lists at gmail.com> wrote:

> You will need to calibrate the sensors to get real/absolute
> measurements out of these devices, in my experience.
> I used them for datalogging and they were +-3C between the three of
> them I had.
> They were self heating by the read process, so you need to let them
> stabilize before calibrating and then read them at the same (slow >
> 60s) intervals as when calibrating.
> I calibrated them to 0C and 60C, determining offset and scaling for
> each of them. Although the thermometers were not very linear to this
> simple calibration, they were OK to +- about 1C within the range.
> I would highly recommend the Maxim DS18B20 as mentioned in the link by
> Chuck if you need something more accurate. They cost under $2 in the
> waterproof version.
> Hat-down to the analog designers @ Maxim designing them so precise
> within this wide temperature and voltage range (±0.5°C Accuracy from
> -10°C to +85°C @ Vdd=3-5.5V)  <-- the probe + reference + A/D convertor
> are at the same hot/cold temperature and at variable voltage for about
> $1 per sensor delivered. Amazing, in my opinion.
> I hope it helps, Tomas
> On Mon, 2017-01-16 at 23:48 -0800, Michael C. Robinson wrote:
> > I am using a Raspberry Pi 3 2016 Model B.
> >
> > I'm trying to use USB TEMPer2 Thermometers to detect the temperature
> > of ice water and the temperature of nearly boiling water.  I am not
> > getting the correct temperatures.
> >
> > pi at raspbypi:~/project $ cat temper-pi.txt
> > http://www.linuxjournal.com/content/temper-pi
> > pi at raspbypi:~/project $
> >
> > pi at raspbypi:~/project $ lsusb
> > Bus 001 Device 010: ID 0c45:7401 Microdia
> > Bus 001 Device 009: ID 0c45:7401 Microdia
> > Bus 001 Device 008: ID 0c45:7401 Microdia
> > Bus 001 Device 007: ID 0409:0058 NEC Corp. HighSpeed Hub
> > Bus 001 Device 005: ID 0a81:0205 Chesen Electronics Corp. PS/2
> > Keyboard+Mouse Adapter
> > Bus 001 Device 011: ID 0c45:7401 Microdia
> > Bus 001 Device 006: ID 0c45:7401 Microdia
> > Bus 001 Device 004: ID 0409:0058 NEC Corp. HighSpeed Hub
> > Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
> > SMSC9512/9514 Fast Ethernet Adapter
> > Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
> > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> > pi at raspbypi:~/project $
> >
> > pi at raspbypi:~/project $ lsusb -t
> > /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc_otg/1p, 480M
> >     |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/5p, 480M
> >         |__ Port 1: Dev 3, If 0, Class=Vendor Specific Class,
> > Driver=smsc95xx, 480M
> >         |__ Port 2: Dev 4, If 0, Class=Hub, Driver=hub/4p, 480M
> >             |__ Port 1: Dev 6, If 0, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 1: Dev 6, If 1, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 4: Dev 11, If 0, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 4: Dev 11, If 1, Class=Human Interface Device,
> > Driver=, 1.5M
> >         |__ Port 3: Dev 5, If 0, Class=Human Interface Device,
> > Driver=usbhid, 1.5M
> >         |__ Port 3: Dev 5, If 1, Class=Human Interface Device,
> > Driver=usbhid, 1.5M
> >         |__ Port 4: Dev 7, If 0, Class=Hub, Driver=hub/4p, 480M
> >             |__ Port 1: Dev 8, If 0, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 1: Dev 8, If 1, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 2: Dev 9, If 0, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 2: Dev 9, If 1, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 4: Dev 10, If 0, Class=Human Interface Device,
> > Driver=, 1.5M
> >             |__ Port 4: Dev 10, If 1, Class=Human Interface Device,
> > Driver=, 1.5M
> > pi at raspbypi:~/project $
> >
> > pi at raspbypi:~/project/temper-python $ cat take_temps.bash
> > #!/bin/bash
> >
> > while (true)
> > do
> >       > sudo temper-poll -p
> >       > sleep 10
> > done
> >
> > @raspbypi:~/project/temper-python $ ./take_temps.bash
> > Found 5 devices
> > Device #0 (bus 1 - port 4): 25.1°C 77.1°F
> > Device #1 (bus 1 - port 2): 24.1°C 75.3°F
> > Device #2 (bus 1 - port 1): 21.5°C 70.7°F
> > Device #3 (bus 1 - port 4): 23.8°C 74.9°F
> > Device #4 (bus 1 - port 1): 23.2°C 73.8°F
> > Found 5 devices
> > Device #0 (bus 1 - port 4): 25.1°C 77.1°F
> > Device #1 (bus 1 - port 2): 24.1°C 75.3°F
> > Device #2 (bus 1 - port 1): 21.5°C 70.7°F
> > Device #3 (bus 1 - port 4): 23.8°C 74.9°F
> > Device #4 (bus 1 - port 1): 23.2°C 73.8°F
> > Found 5 devices
> > Device #0 (bus 1 - port 4): 25.1°C 77.1°F
> > Device #1 (bus 1 - port 2): 24.1°C 75.4°F
> > Device #2 (bus 1 - port 1): 21.5°C 70.7°F
> > Device #3 (bus 1 - port 4): 23.8°C 74.9°F
> > Device #4 (bus 1 - port 1): 23.2°C 73.8°F
> > Found 5 devices
> > Device #0 (bus 1 - port 4): 25.1°C 77.1°F
> > Device #1 (bus 1 - port 2): 24.1°C 75.4°F
> > Device #2 (bus 1 - port 1): 21.5°C 70.7°F
> > Device #3 (bus 1 - port 4): 23.8°C 74.9°F
> > Device #4 (bus 1 - port 1): 23.2°C 73.8°F
> > Found 5 devices
> > Device #0 (bus 1 - port 4): 25.1°C 77.1°F
> > Device #1 (bus 1 - port 2): 24.2°C 75.5°F
> > Device #2 (bus 1 - port 1): 21.5°C 70.7°F
> > Device #3 (bus 1 - port 4): 23.8°C 74.9°F
> > Device #4 (bus 1 - port 1): 23.2°C 73.8°F
> > Found 5 devices
> > Device #0 (bus 1 - port 4): 25.1°C 77.1°F
> > Device #1 (bus 1 - port 2): 24.2°C 75.5°F
> > Device #2 (bus 1 - port 1): 21.5°C 70.7°F
> > Device #3 (bus 1 - port 4): 23.8°C 74.9°F
> > Device #4 (bus 1 - port 1): 23.2°C 73.8°F
> > ^C
> >
> > Please note the following changes to Raspbian, Jessie I believe...
> >
> > pi at raspbypi:~/project/temper-python $ cat /boot/cmdline.txt
> > dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1
> > root=/dev/mmcblk0p7 rootfstype=ext4 elevator=deadline fsck.repair=yes
> > rootwait quiet splash plymouth.ignore-serial-consoles
> > usbhid.quirks=0x0c45:0x7401:0x4
> >
> > pi at raspbypi:~/project/temper-python $ cat /etc/udev/rules.d/99-
> > tempsensor.rules SUBSYSTEMS=="usb", ACTION=="add",
> > ATTRS{idVendor}=="0c45", ATTRS{idProduct}=="7401", MODE="666"
> >
> > The above changes allow non non root users to use temper-python and
> > they should prevent problems with the sensors being identified as
> > keyboards?
> >
> > The following is an excerpt out of dmesg:
> >
> > [  206.199665] usb 1-1.2.1: new low-speed USB device number 14 using
> > dwc_otg
> > [  206.317607] usb 1-1.2.1: New USB device found, idVendor=0c45,
> > idProduct=7401
> > [  206.317619] usb 1-1.2.1: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> > [  206.317626] usb 1-1.2.1: Product: TEMPer2_M12_V1.3
> > [  206.317633] usb 1-1.2.1: Manufacturer: RDing
> > [  206.409673] usb 1-1.2.4: new low-speed USB device number 15 using
> > dwc_otg
> > [  206.527634] usb 1-1.2.4: New USB device found, idVendor=0c45,
> > idProduct=7401
> > [  206.527645] usb 1-1.2.4: New USB device strings: Mfr=1, Product=2,
> > SerialNumber=0
> > [  206.527653] usb 1-1.2.4: Product: TEMPer2_M12_V1.3
> > [  206.527659] usb 1-1.2.4: Manufacturer: RDing
> >
> > I noticed that the Linux Journal article is old and that the sensors
> > I
> > have are likely newer than when the article was written.  The seller
> > said Linux compatible, but is that true?
> > _______________________________________________
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