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test-and-measurement:analog-discovery-pro-3x50:linux-thingspeak-demo [2021/10/13 21:06] – external edit 127.0.0.1test-and-measurement:analog-discovery-pro-3x50:linux-thingspeak-demo [2022/10/04 11:38] (current) – external edit 127.0.0.1
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 +====== Sending Data to ThingSpeak.com with Analog Discovery Pro (ADP3450/ADP3250) in Linux Mode ======
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:thingspeak_result_new.png?600 |}}
 +~~TechArticle~~
  
 +===== Overview =====
 +ThingSpeak, created by MathWorks, is an online platform for collecting, viewing, and analyzing data in the cloud. This guide runs through the steps required to send data captured by the Analog Discovery Pro (ADP3450/ADP3250) up to ThingSpeak and ends with an example, which uses the Pmod MIC3 to capture a sound wave, then, from the measurements, the Analog Discovery Pro calculates the noise level. The noise level measurements are visualized in four different ways on the ThingSpeak channel.
 +
 +To view examples for uploading data to ThingSpeak with other Test & Measurement devices, or with Analog Discovery Pro in Standard mode, check this guide: [[software:waveforms:waveforms-sdk:thingspeak]].
 +
 +To take measurements and to upload data to ThingSpeak without the help of a PC, one can use the Analog Discovery Pro (ADP3450/ADP3250) in Linux mode. In this mode, the Test & Measurement device will run the script independently and can accept commands from any connected terminal.
 +
 +To successfully run this example, you will need the latest Linux version for your device. To update the ADP3450/ADP3250 Linux image, follow this guide: [[test-and-measurement:analog-discovery-pro-3x50:recover-linux-mode]].
 +----
 +
 +===== Inventory =====
 +<WRAP group>
 +== Hardware ==
 +  * [[test-and-measurement:analog-discovery-pro-3x50:start|Analog Discovery Pro (ADP3450/ADP3250)]]
 +  * [[https://digilent.com/shop/pmod-mic3-mems-microphone-with-adjustable-gain/|Pmod MIC3]]
 +  * A FAT/FAT32 USB drive
 +== Software ==
 +<WRAP group><WRAP half column>
 +  * On PC:
 +    * [[software:waveforms:waveforms-3:start]]
 +    * [[https://ttssh2.osdn.jp/|Tera Term]], or any other terminal emulator of your choice
 +    * [[https://code.visualstudio.com/|Visual Studio Code]], or any other editor of your choice (you can choose to use a text editor on the Analog Discovery Pro instead).
 +</WRAP><WRAP half column>
 +  * On Analog Discovery Pro:
 +    * [[https://www.python.org/downloads/|Python 3]]
 +    * WaveForms SDK - preinstalled
 +    * [[https://www.nano-editor.org/|GNU nano]], or any other editor of your choice (you can choose to use a text editor on the PC instead).
 +</WRAP></WRAP>
 +</WRAP>
 +
 +**Note:** //WaveForms can be installed by following the [[software:waveforms:waveforms-3:getting-started-guide]].//
 +
 +**Note:** //In this guide, the Python script will be created and edited on the PC, then copied to an USB drive to move it on the Analog Discovery Pro. If you choose to edit the script directly on your Test & Measurement device, the steps are similar.//
 +----
 +
 +===== Setting Up the Analog Discovery Pro (ADP3450/ADP3250) =====
 +<WRAP group>
 +The first step is to connect your device to the internet. If you already have internet enabled for Linux mode, just connect the Ethernet cable and skip this step.
 +</WRAP>
 +
 +--> Connect the Analog Discovery Pro (ADP3450/ADP3250) to the Internet #
 +<WRAP group>
 +{{section>test-and-measurement:analog-discovery-pro-3x50:connect-to-the-internet#setting_up_the_connection&noheader}}
 +</WRAP>
 +<--
 +----
 +
 +<WRAP group>
 +Now boot into Linux mode. If your device already is in Linux mode, just skip this step.
 +
 +--> Booting into Linux Mode #
 +<WRAP group><WRAP column half>
 +Mode selection can be done through WaveForms using the Device Manager. With the Analog Discovery Pro connected to the host computer by Ethernet, open WaveForms. If the Device Manager hasn't opened yet, then click Settings -> Device Manager.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:eth_st.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Select the Analog Discovery Pro from the device menu, then click the Boot button. The Boot Mode window should open. By default, Standard Mode which allows the user to communicate with the instrumentation device over USB or Ethernet will be selected.
 +
 +To change to Linux Mode, select Linux, then click "Apply & Reboot".
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:linux_mode.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +At this time, an audible click should be heard and the Analog Discovery Pro will disconnect from WaveForms. About 10-15 seconds should pass before it reconnects. Confirm that the second column next to the Analog Discovery Pro says "ETH:LX", confirming the mode has successfully been switched.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:eth_lx.png?400 |}}
 +</WRAP></WRAP>
 +<--
 +</WRAP>
 +----
 +
 +===== Configuring a ThingSpeak Channel =====
 +<WRAP group><WRAP column half>
 +Go to [[http://thingspeak.com|thingspeak.com]] and sign in or sign up.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thingspeak_sign_in.png?600 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +In the //Channels// menu select //My Channels// and create a **New Channel**.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thinspeak_newchannel.png?600 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Configure the channel settings, name, and fields. The field will be the containers for your data. Configure a field for every data type that you want to store/process.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thingspeak_channelset.png?600 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Under //API Keys//, note the **Write API Key** that will be needed to push data to the server from the custom application or script. The **Read API Key** can be used to access stored data.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thingspeak_keys.png?600 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +When uploading data to a ThingSpeak channel, it will be displayed field-by-field on different plots. To modify these default plots, or add other data visualization methods to your channel, you can use the visualization or widget presets, you can modify the MATLAB code of the default plots, or you can write your own code to visualize the data.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thingspeak_visualization.png?600 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +To make your visualizations/data publicly available, go to **Sharing** and select the option you want to set. //"iframe"// tags can be used to embed graphical elements from ThingSpeak into your webpages.
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thingspeak_sharing.png?600 |}}
 +</WRAP></WRAP>
 +----
 +
 +===== Script Overview =====
 +<WRAP group>
 +The complete source code of this project can be downloaded from here: {{ :reference:software:waveforms:waveforms-sdk:pmodmic3_to_thingspeak.zip |PmodMIC3_to_ThingSpeak.zip}}. It contains the Python script used to control the Pmod MIC3, to convert the measured data, and to upload the results to ThingSpeak.
 +
 +Discussing in detail the usage of the WaveForms SDK is beyond the scope of this project. For more information about it, check [[test-and-measurement:digital-discovery:controlling-digital-discovery-with-labview:start]], [[test-and-measurement:analog-discovery-2:ad2-motor-debugger:start]], the [[software:waveforms:waveforms-sdk:reference-manual]], and the examples available in the WaveForms installation directory.
 +
 +For a demo project with Pmod MIC3, check [[https://projects.digilentinc.com/56469/using-the-pmod-mic3-with-arduino-uno-fc0daa|Using the Pmod MIC3 with Arduino Uno]].
 +</WRAP>
 +
 +<WRAP group><WRAP column half>
 +At the beginning of the script, the necessary modules are imported, then the address of the ThingSpeak channel is defined. To access your own channel, use your own API key in the address.
 +
 +DIO lines used to communicate with the Pmod, as well as global variables controlling communication and data processing, are also defined here. Before calling any function from the WaveForms SDK, it is necessary to load the dynamic library.
 +</WRAP><WRAP column half><code python>
 +"""import modules"""
 +import sys  # This module provides access to some objects used or maintained by the interpreter and to functions that interact strongly with the interpreter
 +import time  # This module provides various functions to manipulate time values
 +from ctypes import *  # C data types in Python
 +import signal    # This module provides mechanisms to use signal handlers
 +import requests  # Requests HTTP Library
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +"""variables for communication with ThingSpeak"""
 +url = "https://api.thingspeak.com/update?api_key=E**************7"
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +"""variables for connections and SPI"""
 +# define the communication frequency in Hz
 +spi_frequency = 1e6
 +# pin used for chip select (DIO 24 on Digital Discovery)
 +spi_CS = 0
 +# pin used for master in - slave out (DIO 25 on Digital Discovery)
 +spi_MISO = 1
 +# pin used for serial clock (DIO 26 on Digital Discovery)
 +spi_SCK = 2
 +# samples to average
 +AVERAGE = 1000
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +"""load the WaveForms SDK"""
 +if sys.platform.startswith("win"):
 +    dwf = cdll.LoadLibrary("dwf.dll")  # on Windows
 +
 +elif sys.platform.startswith("darwin"):
 +    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")  # on macOS
 +
 +else:
 +    dwf = cdll.LoadLibrary("libdwf.so")  # on Linux
 +
 +
 +</code></WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +For repeating tasks like resetting and closing the used instruments, displaying error messages, and reading data on SPI, user defined functions are used. Certain keywords and interrupt handlers must also be defined before using them.
 +</WRAP><WRAP column half><code python>
 +"""function to reset all instruments, close the device and quit"""
 +
 +
 +def close_device(signum=0, frame=0):
 +    signum = frame  # dummy
 +    frame = signum  # dummy
 +    print("Device disconnected\n")
 +    dwf.FDwfDigitalSpiReset(hdwf)
 +    dwf.FDwfDigitalOutReset(hdwf)
 +    dwf.FDwfDigitalInReset(hdwf)
 +    dwf.FDwfAnalogIOEnableSet(hdwf, c_int(False))
 +    dwf.FDwfDeviceClose(hdwf)
 +    sys.exit()
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +
 +"""function to display the last error message"""
 +
 +
 +def display_error(err_msg="No error"):
 +    if err_msg == "No error":
 +        err_msg = create_string_buffer(512)
 +        dwf.FDwfGetLastErrorMsg(err_msg)
 +        err_msg = str(err_msg.value)[2:-1]
 +        if err_msg == "":
 +            err_msg = "unknown error"
 +    print("Error: " + err_msg + "\n")
 +    return err_msg
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +
 +"""function to read spi data"""
 +
 +
 +def spi_read():
 +    lsb = c_int()
 +    msb = c_int()
 +    dwf.FDwfDigitalSpiSelect(hdwf, spi_CS, LOW)  # activate
 +    time.sleep(.001)  # millisecond
 +    spi_command = c_int(0)
 +    dwf.FDwfDigitalSpiWriteRead(hdwf, spi_mode, c_int(8), byref(
 +        spi_command), c_int(1), byref(lsb), c_int(1))  # read 1 byte
 +    dwf.FDwfDigitalSpiWriteRead(hdwf, spi_mode, c_int(8), byref(
 +        spi_command), c_int(1), byref(msb), c_int(1))  # read 1 byte
 +    time.sleep(.001)  # millisecond
 +    dwf.FDwfDigitalSpiSelect(hdwf, spi_CS, HIGH)  # deactivate
 +    return lsb.value | (msb.value << 8)
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +
 +"""keyboard interrupt handler and keywords"""
 +signal.signal(signal.SIGINT, close_device)
 +
 +HIGH = c_int(1)
 +LOW = c_int(0)
 +DwfDigitalOutIdleZet = c_int(3)
 +
 +</code></WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Before using a Test and Measurement Device, it needs to be connected to the host computer. To safely connect it, cases in which the device is used by other software, or is not available from some other reason, should be evited.
 +</WRAP><WRAP column half><code python>
 +"""open the connected T&M device"""
 +device_count = c_int()
 +dwf.FDwfEnum(c_int(0), byref(device_count))  # count devices
 +
 +if device_count.value == 0:
 +    # terminate the program if no devices are connected
 +    display_error("No connected device detected")
 +    sys.exit()
 +
 +for device_index in range(device_count.value):
 +    # get the name of the device
 +    device_name = create_string_buffer(64)
 +    dwf.FDwfEnumDeviceName(device_index, device_name)
 +
 +    # connecting the device
 +    hdwf = c_int()
 +    dwf.FDwfDeviceOpen(device_index, byref(hdwf))
 +
 +    # check for success
 +    if hdwf.value != 0:
 +        break
 +
 +if hdwf.value == 0:
 +    # terminate the program if the device can't be connected
 +    display_error()
 +    sys.exit()
 +
 +# display message
 +device_name = str(device_name.value)[2:-1]
 +print(device_name + " is connected\n")
 +
 +</code></WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +To start communicating with the connected Pmod, it has to be powered. In devices which support this feature, the output voltage of the power supply should be set to 3.3V, as this is the recommended operating voltage of the Pmod. However, a supply voltage of 5V shouldn't damage the Pmod, according to its datasheet.
 +
 +After the microphone is powered, the SPI interface should be initialized. After setting the communication parameters, a dummy read is performed to start driving the serial clock.
 +</WRAP><WRAP column half><code python>
 +"""start the power supply"""
 +if device_name == "Digital Discovery" or device_name == "Analog Discovery Pro 3450" or device_name == "Analog Discovery Pro 3250":
 +    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(
 +        0), c_double(3.3))  # set digital voltage to 3.3V
 +elif device_name == "Analog Discovery 2" or device_name == "Analog Discovery Studio":
 +    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(
 +        0), c_double(True))  # enable positive supply
 +    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(
 +        1), c_double(3.3))  # set voltage to 3.3V
 +elif device_name == "Analog Discovery":
 +    dwf.FDwfAnalogIOChannelNodeSet(hdwf, 0, 0, 1)  # enable positive supply
 +else:
 +    display_error("Can't start the power supply. The device is incompatible.")
 +    close_device()
 +dwf.FDwfAnalogIOEnableSet(hdwf, c_int(True))  # master enable
 +print("Power supply started\n")
 +time.sleep(5)  # seconds
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +"""initialize the spi communication"""
 +dwf.FDwfDigitalSpiFrequencySet(hdwf, c_double(
 +    spi_frequency))    # set clock frequency
 +dwf.FDwfDigitalSpiClockSet(hdwf, spi_SCK)   # SCK pin
 +dwf.FDwfDigitalSpiDataSet(hdwf, c_int(1), spi_MISO)  # MISO pin
 +dwf.FDwfDigitalSpiIdleSet(hdwf, c_int(1), DwfDigitalOutIdleZet)  # idle state
 +spi_mode = c_int(1)  # MOSI/MISO mode
 +dwf.FDwfDigitalSpiModeSet(hdwf, c_int(0))   # CPOL=0 CPHA=0 mode
 +dwf.FDwfDigitalSpiOrderSet(hdwf, c_int(1))  # MSB first
 +dwf.FDwfDigitalSpiSelect(hdwf, spi_CS, HIGH)  # CS pin
 +
 +# dummy read to start driving the channels, clock and data
 +dwf.FDwfDigitalSpiReadOne(hdwf, c_int(1), c_int(0), c_int(0))
 +
 +print("SPI interface initialized\n")
 +time.sleep(1)  # seconds
 +
 +</code></WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +Measurements are done continuously until Ctrl+C is pressed. The results of the measurements are averaged, then converted to dB (this conversion is just an approximation of the true noise level).
 +
 +The result of the conversion is pushed to the ThingSpeak channel. If a communication error appears, or the process is interrupted, the used instruments are reset, and the program finishes.
 +</WRAP><WRAP column half><code python>
 +"""measure and send data to ThingSpeak"""
 +print("Measuring and uploading data. Press ctrl+c to stop...\n")
 +
 +while True:
 +    try:
 +        # receive initial data
 +        level = 0
 +
 +        # average data
 +        for index in range(AVERAGE):
 +            level += (spi_read() / 10) / AVERAGE
 +
 +        # calculate noise level
 +        db = 729.0532027 - level * 0.4239354122 + \
 +            pow(level, 2) * 0.8875384813 * 1e-4 - \
 +            pow(level, 3) * 0.6195715088 * 1e-8
 +
 +        # send data and check for errors
 +        send_state = requests.get(url+"&field1="+str(db))
 +        if send_state.status_code != 200:
 +            display_error("Can't communicate with ThingSpeak")
 +            close_device()
 +    except KeyboardInterrupt:  # exit if Ctrl+C is pressed
 +        break
 +
 +# ----------------------------------------------------------------------------------------------------------
 +
 +"""reset and close the device"""
 +close_device()
 +
 +</code></WRAP></WRAP>
 +----
 +
 +===== Hardware Setup =====
 +<WRAP group><WRAP column half>
 +The Pmod MIC3 communicates on a SPI interface which will be connected to the Analog Discovery Pro's digital I/O lines as follows: SS to DIO line 0, MISO to DIO 1 and SCK to DIO 2. Power to the Pmod is also supplied by the Test and Measurement device used, so the VCC pin of the Pmod should be connected to the VIO pin on Analog Discovery Pro, and the grounds of the two devices should be connected together, as shown in the image to the right.
 +
 +Prepare a FAT/FAT32 USB drive (while this is the default format for many USB drives, you may need to format it). Copy the Python script (PmodMIC3_to_Thingspeak.py) to the USB drive's root directory. You can also use your own Python script as well, just copy it to the root directory of the USB drive. Plug the USB drive into the back of the Analog Discovery Pro.
 +</WRAP><WRAP column half>
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:wiring_adp3450.png?600 |}}
 +</WRAP></WRAP>
 +----
 +
 +===== Running the Script and Results =====
 +<WRAP group>
 +To command the ADP3450/ADP3250, you will have to connect to it through a terminal. To do so, you will need a terminal emulator program, like [[https://ttssh2.osdn.jp/|Tera Term]], [[https://www.chiark.greenend.org.uk/~sgtatham/putty/|PuTTY]] for Windows, or [[https://play.google.com/store/apps/details?id=de.kai_morich.serial_wifi_terminal|Serial WiFi Terminal]] for Android (the Analog Discovery Pro can now be controlled from any device connected to the internet).
 +
 +Tera Term will be used in this guide, but the steps are similar for each of the mentioned programs.
 +</WRAP>
 +
 +<WRAP group><WRAP half column>
 +Open WaveForms and open the //Device Manager// from the //Settings// menu, then select your device and open its Network Settings by clicking on the //Network// button. Note the IP address assigned to your device and close WaveForms.
 +</WRAP><WRAP half column>
 +{{ :reference:software:waveforms:waveforms-sdk:ip_address.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Open the terminal emulator and establish a new Secure Shell (SSH) connection to the Analog Discovery Pro's IP address. You can leave every other setting as default. When required, enter the user name and the password:
 +
 +|<50% 25% 25%>|
 +^ user name: | digilent |
 +^ password: | digilent |
 +
 +You should have now a connected terminal.
 +</WRAP><WRAP half column>
 +{{ :reference:software:waveforms:waveforms-sdk:ssh_connect.png?400 |}}
 +</WRAP></WRAP>
 +----
 +
 +<WRAP group><WRAP half column>
 +As the Python script uses the //requests// module to communicate with ThingSpeak, this module should be installed first, along with Python 3, by entering the following command into the terminal:
 +
 +<code>sudo apt-get install python3-requests</code>
 +
 +When required, enter the sudo password:
 +
 +|<50% 25% 25%>|
 +^ sudo password: | digilent |
 +</WRAP><WRAP half column>
 +{{ :reference:software:waveforms:waveforms-sdk:install_requests.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Check the drive letter and partition number of the USB drive by entering the following command:
 +
 +<code>sudo fdisk -l</code>
 +
 +It should look like ///dev/sd<drive letter><partition number>//. This guide will use ///dev/sda1// in its text and images, but this may differ with your device. Care must be taken to match the drive letter and partition number of your USB drive.
 +</WRAP><WRAP half column>
 +{{ :reference:software:waveforms:waveforms-sdk:drive_identification.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +Make the drive contents accessible by entering the command:
 +
 +<code>sudo mount /dev/sda1 /mnt</code>
 +
 +And then:
 +
 +<code>cd /mnt</code>
 +</WRAP><WRAP half column>
 +{{ :reference:software:waveforms:waveforms-sdk:drive_mounting.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP half column>
 +You can start the Python script by entering the command below, where //PmodMIC3_to_Thingspeak.py// is the name of the script file.
 +
 +<code>sudo python3 ./PmodMIC3_to_Thingspeak.py</code>
 +</WRAP><WRAP half column>
 +{{ :reference:software:waveforms:waveforms-sdk:script_running.png?400 |}}
 +</WRAP></WRAP>
 +
 +<WRAP group><WRAP column half>
 +The indicators can be added from the channel's **Private/Public View**, with the **Add Visualization**, **Add Widget**, **MATLAB Analysis**, or **MATLAB Visualization** buttons.
 +
 +The measured noise levels can be plotted against time or displayed on a gauge widget. A histogram of the measured values can also be displayed, along with a virtual LED, to indicate dangerous noise levels. One important MATLAB function to use in data processing is [[https://www.mathworks.com/help/thingspeak/thingspeakread.html|thingSpeakRead()]].
 +</WRAP><WRAP column half>
 +{{ :reference:software:waveforms:waveforms-sdk:thingspeak_process.png?600 |}}
 +{{ reference:test-and-measurement:analog-discovery-pro-3x50:thingspeak_result_new.png?600 |}}
 +</WRAP></WRAP>
 +----
 +
 +===== Next Steps =====
 +Now that data can be transferred between the Analog Discovery Pro and ThingSpeak, the script can be modified as needed for your project.
 +
 +For more information on WaveForms SDK, see its [[software:waveforms:waveforms-sdk:start|Resource Center]].
 +
 +For technical support, please visit the [[https://forum.digilentinc.com/forum/8-test-and-measurement/|Test and Measurement]] section of the Digilent Forums.