ExpEYES/C2/Communicating-to-ExpEYES-using-Python/English-timed

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Time Narration
00:01 Hello everyone. Welcome to this tutorial on Communicating to ExpEYES using Python.
00:07 In this tutorial, we will learn:
  • Introduction to Python
  • Measure AC voltage using Plot window and Python
  • Generate a Sine wave
  • Measure external and internal voltages using Python
00:22 * Measure capacitance and resistance using Plot window & Python
  • Generate a Square wave
  • Show connections and circuit diagrams for our experiments.
00:34 Here I am using,
  • ExpEYES version 3.1.0
  • Ubuntu Linux OS version 14.10
00:43 To follow this tutorial, you should be familiar with:
  • ExpEYES Junior interface
  • Basic Python programming.
00:52 If not, for relevant tutorials, please visit our website.
00:56 Let's begin with the introduction to Python.
01:00 Python is simple and easy to learn powerful programming language.
  • It is Free and Open Source, cross platform high level language.
  • It has effective approach to Object oriented program.
01:15 Let's make sure that Python is installed on our system.
01:18 Press CTRL+ ALT and T keys to open the Terminal.
01:22 To start Python interpreter, type: "python" and press Enter. Details regarding default version of Python will be displayed on the Terminal.
01:36 The displayed three angle brackets indicate Python prompt(>>>). Now you are ready to type commands.
01:44 For more details about Python programming, please visit our website.
01:49 I will discuss about the channels on the top Panel of the device.
01:54 On the top Panel, each terminal is assigned to a specific channel number.
02:00 For example- channel 1 is assigned to A1 and channel 2 to A2.
02:07 I will show how to connect wires to the device.
02:11 Device has screw terminals on either side.
02:15 To make the connection, we insert wires into the terminals and tighten the screws. Here A2 is connected to SINE.
02:22 This is the circuit diagram.
02:28 Let's perform an experiment to measure the voltage of A2 and show its Sine wave.
02:36 Let's see the result on the Plot window.
02:39 On the Plot window, click on A2 to display the voltage of A2. Voltage of A2 is displayed below.
02:48 Click on A2 and drag to channel CH1. When we drag A2 to CH1, input data of A2 is assigned to CH1.
02:59 Move the msec/div slider to show the Sine wave. Click on A2 to show change in voltages of A2.
03:09 Click on CH1 and drag to FIT. The voltage and frequency of A2 are displayed on the right.
03:16 We will perform the same experiment and measure voltage of A2 using Python.
03:23 Please note, to avoid errors on Python interpreter:
  • Connect the device to the system.
  • Close the Plot window.
03:31 To import eyes library from ExpEYES, type at the prompt "import expeyes.eyesj". Press Enter.
03:40 Type: p=expeyes.eyesj.open() and press Enter. open() function returns an object if hardware is found.
03:53 These lines will load the ExpEYES library and establish connection to the device.
03:58 To view the voltage of A2, type: "print p.get_voltage within brackets 2" and press Enter.
04:08 Output shows voltage of A2. Similarly, we can show the various voltages of A2.
04:15 Voltage of A2 changes as it is an AC voltage.
04:20 To generate plots using Python interpreter,

install python-matplotlib library using Synaptic Package Manager.

04:30 I have already installed python-matplotlib library on my system.
04:36 To generate plots on Windows Operating system:
04:40 Download and install,
  • matplotlib version 1.4.3
  • numpy version 1.9 or above.
04:49 Copy the installed ExpEYES files and drivers and paste in C drive.
04:55 To generate Sine wave, at the python prompt, type: "import expeyes.eyesj" and press Enter.
05:05 Type p=expeyes.eyesj.open() and press Enter as before.
05:12 Type: from pylab import *(asterisk). from pylab import * is a program from matplotlib library. Press Enter.
05:26 Type: ion(). This command sets pylab interactive mode.

Press Enter.

05:35 Type: t,v=p.capture within brackets 2,200,100.

"t", "v" are time and voltage vectors.

05:50 2 is channel number for A2, 200 is the number of data points, 100 is a time interval between subsequent measurements.
06:02 Press Enter.
06:04 To view the output, type: plot within brackets t,v. plot within brackets t,v generates a Sine wave on a new window.
06:15 Press Enter.
06:18 We can generate a Sine wave using the above commands on Windows command prompt as well.
06:26 Next, let's measure voltage of A1 using a battery as an external voltage source.
06:32 To measure external voltage source, Ground(GND) is connected to A1 through a battery of 3V.
06:39 This is the circuit diagram. We will show the value of A1 using Python interpreter.
06:46 At the python prompt:

Type: "import expeyes.eyesj", press Enter.

06:53 Type: p=expeyes.eyesj.open(), and press Enter.
06:59 Type: print p.get_voltage within brackets 1 and pressEnter.
07:07 Here, Channel 1 is assigned to A1. Voltage of A1 is displayed on the terminal.
07:14 Let's measure voltage of A1 using PVS as internal voltage source.
07:20 In this experiment, PVS is connected to A1.
07:24 This is the circuit diagram.
07:28 Back to the terminal. Type: print p.set_voltage within brackets 3 and press Enter.
07:39 Here, voltage of PVS will be set to 3 volts. Voltage of PVS is displayed.
07:47 Type: "print p.get_voltage(1)" and press Enter. voltage of A1 is displayed on the terminal.
07:45 Now, I will demonstrate AC and DC components of a voltage using capacitor and resistor. And also, generate a square wave.
08:11 In this experiment,
  • A1 is connected to SQR1.
  • SQR1 is connected to A2 through a capacitor.
  • A2 is connected to ground(GND) through 200k resistor.
08:25 This is the circuit diagram.
08:27 Let's see the result on the Plot window.
08:31 On the Plot window, click on Measure C on IN1 button.
08:36 Capacitance of IN1 is displayed as -0.6 pF (pico farads).
08:42 Click on Measure R on SEN button. Resistance of SEN is displayed as 560 Ω(ohms).
08:51 Please note you may get slightly different values of Capacitance & Resistance.
08:57 Click on SQ1 and drag to CH1.

SQ1 is assigned to channel CH1.

09:04 Click on A2 and drag to CH2.

A2 is assigned to channel CH2.

09:12 Click on SQR1 check box to show the Square waves. Move the msec/div slider to adjust the waves.
09:23 Click on CH2, drag to FIT. Voltage and frequency of A2 is displayed on the right side.
09:32 We will perform the same experiment to measure Capacitance, Resistance and generate a Square wave using Python interpreter.
09:41 At the python prompt, type: "import expeyes.eyesj" and press Enter.
09:50 Type: p=expeyes.eyesj.open() and press Enter.
09:58 To display the Capacitance value, type: p.measure_cap( ) and press Enter.
10:07 Capacitance value is displayed on the terminal.
10:11 To display the Resistance value, type: p.measure_res() and press Enter.

Resistance value is displayed on the terminal.

10:24 To generate a Square wave, type: from pylab import *(asterisk) and press Enter.

Type: ion() and press Enter.

10:36 Type: print p.set_sqr1 within brackets 100 and press Enter. Here 100 is the frequency of the square wave.
10:49 Type: t,v=p.capture within brackets 6,400,100 and press Enter.
11:00 Type: plot within brackets t,v. plot within brackets t,v generates a square wave on a new window.
11:12 Press Enter.
11:14 Let's summarize.
11:17 In this tutorial, we have learnt:
  • Introduction to Python
  • Measure AC voltage using Plot window & Python
  • Generate a Sine wave
  • Measure external and internal voltages using Python
11:33 Measure capacitance & resistance using Plot window & Python
  • Generate a Square wave
  • Show connections & circuit diagrams for our experiments.
11:45 As an assignment,
  • Measure the resistance of your finger using Plot window.
  • Using python, generate a combination of Sine and Square waves.
11:56 Show circuit diagrams for the above experiment.
11:59 This video summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.
12:07 We conduct workshops using Spoken Tutorials and give certificates. Please contact us.
12:13 The Spoken Tutorial Project is funded by NMEICT, MHRD Government of India.
12:20 This tutorial is contributed by Kaushik Datta and Madhuri Ganapathi.

Thank you for joining.

Contributors and Content Editors

Pratik kamble, Ranjana, Sandhya.np14