Integrating Travis CI and Codacy in PSLab Repositories

Continuous Integration Testing and Automated Code Review tools are really useful for developing better software, improving code and overall quality of the project. Continuous integration can help catch bugs by running tests automatically and to merge your code with confidence.

While working on my GsoC-16 project, my mentors guided and helped me to integrate Travis CI and Codacy in PSLab github repositories. This blog post is all about integrating these tools in my github repos, problems faced, errors occurred and the test results.

travisTravis CI is a hosted continuous integration and deployment system. It is used to build and test software projects hosted on github. There are two versions of it, travis-ci.com for private repositories, and travis-ci.org for public repositories.

Read : Getting started with Travis CI

Travis is configured with the “.travis.yml” file in your repository to tell Travis CI what to build. Following is the code from ‘.travis.yml‘ file in our PSLab repository. This repo contains python communication library for PSLab.

language: python
python:
  - "2.6"
  - "2.7"
  - "3.2"
  - "3.3"
  - "3.4"
# - "3.5"
# command to install dependencies
# install: "pip install -r requirements.txt"
# command to run tests
script: nosetests

With this code everything worked out of the box (except few initial builds which errored because of missing ‘requirements.txt‘ file) and build passed successfuly 🙂 🙂

Later Mario Behling added integration to FOSSASIA Slack Channel.

Slack notifications

Travis CI supports notifying  Slack channels about build results. On Slack, set up a new Travis CI integration. Select a channel, and you’ll find the details to paste into your ‘.travis.yml’. Just copy and paste the settings, which already include the proper token and you’re done.

The simplest configuration requires your account name and the token.

notifications:
  slack: '<account>:<token>'     
notifications:
  slack: fossasia:***tokenishidden****

Import errors in Travis builds of PSLab-apps Repository

PSLab-apps repository contains PyQt bases apps for various experiments. The ‘.travis.yml‘ file mentioned above gave several module import errors.

$ python --version
Python 3.2.5
$ pip --version
pip 6.0.7 from /home/travis/virtualenv/python3.2.5/lib/python3.2/site-packages (python 3.2)
Could not locate requirements.txt. Override the install: key in your .travis.yml to install dependencies.
0.33s$ nosetests
E
======================================================================
ERROR: Failure: ImportError (No module named sip)

The repo is installable and PSLab was working fine on popular linux distributions without any errors. I was not able to find the reason for build errors. Even after adding proper ‘requirements.txt‘ file,  travis builds errored.

On exploring the documentation I could figure out the problem.

Travis CI Environment uses separate virtualenv instances for each Python version. System Python is not used and should not be relied on. If you need to install Python packages, do it via pip and not apt. If you decide to use apt anyway, note that Python system packages only include Python 2.7 libraries (default python version). This means that the packages installed from the repositories are not available in other virtualenvs even if you use the –system-site-packages option. Therefore I was getting Import module errors.

This problem was solved by making following changes in the ‘.travis.yml‘ file

language: python

python:
  #- "2.6"
  - "2.7"
  #- "2.7_with_system_site_packages"
  - "3.2"
  #- "3.2_with_system_site_packages"
  - "3.3"
  - "3.4"
before_install:
    - sudo mkdir -p /downloads
    - sudo chmod a+rw /downloads
    - curl -L http://sourceforge.net/projects/pyqt/files/sip/sip-4.16.5/sip-4.16.5.tar.gz -o /downloads/sip.tar.gz 
    - curl -L http://sourceforge.net/projects/pyqt/files/PyQt4/PyQt-4.11.3/PyQt-x11-gpl-4.11.3.tar.gz -o /downloads/pyqt4.tar.gz
    # Builds
    - sudo mkdir -p /builds
    - sudo chmod a+rw /builds

install:
    - export DISPLAY=:99.0
    - sh -e /etc/init.d/xvfb start
    - sudo apt-get install -y libqt4-dev
    - sudo apt-get install -y mesa-common-dev libgl1-mesa-dev libglu1-mesa-dev
#    - sudo apt-get install -y python3-sip python3-sip-dev python3-pyqt4 cmake
    # Qt4
    - pushd /builds
    # SIP
    - tar xzf /downloads/sip.tar.gz --keep-newer-files
    - pushd sip-4.16.5
    - python configure.py
    - make
    - sudo make install
    - popd
    # PyQt4
    - tar xzf /downloads/pyqt4.tar.gz --keep-newer-files
    - pushd PyQt-x11-gpl-4.11.3
    - python configure.py -c --confirm-license --no-designer-plugin -e QtCore -e QtGui -e QtTest
    - make
    - sudo make install
    - popd
 # - "3.5"
# command to install dependencies
#install: "pip install -r requirements.txt"
# command to run tests
script: nosetests

notifications:
  slack: fossasia:*****tokenishidden*******


codacy

Codacy is an automated code analysis and review tool that helps developers ship better software, faster. With Codacy integration one can get static analysis, code complexity, code duplication and code coverage changes in every commit and pull request.

Read : Integrating Codacy in github is here.

Codacy integration has really helped me to understand and enforce code quality standard. Codacy gives you impact of every pull request in terms of quality and errors directly into GitHub.

codacy check

Codacy also grades your project in different categories like Code Complexity, Compatibility, security, code style, error prone etc. to help you better understand the overall project quality and what are the areas you should improve.

Here is a screen-shot of Codacy review for PSLab-apps repository.

codacyreport

I am extremely happy to share that my learning adventure has got  Project Certification at ‘A’ grade. Project quality analysis shows that more than 90% of the work has A grade 🙂 🙂

Travis CI and Codacy Badges for my GSoC Repositories:

PSLab : Python Library for Communication with PSLab

Travis CI Badge         Codacy Badge

PSLab-apps : Qt based GUI applications for PSLab

Travis CI Badge         Codacy Badge

Pocket Science Lab : ExpEYES Programs, Sensor Plugins

Travis CI Badge         Codacy Badge

That’s all for now. Have a happy coding, testing and learning 🙂 🙂

Design Your Own Experiments With PSLab

PSLab, with its simple and open architecture allows programmers, hobbyists to use the tool for various measurements and to develop new experiments with simple python code.

One of the main target group, the PSLab is aimed at, is high-school science teachers and students, who may or may-not be familiar with the computer programming. For such users it is difficult to design or develop new experiments on their own. They may also find it difficult to fetch the data and plot required graphs, if a ready-made GUI is not available for that particular experiment.

To enable such users to quickly design a simple experiment for studying various phenomena, we have developed a simple Experiment Designer GUI. This incorporates few controls, read-back elements and easy functions to select parameters and plot graphs.

The screen shot of the ‘Design Your Own Experiment’ GUI along with the App-window is here..

experiment designer1

Experiment Designer allows the user to define the control and read-back sequences of parameters and execute them.

Features of “Design Your Own Experiment” GUI

  • Configure Experiment : Here user can select the required channels ( manual / sweep / read-back). One can also add a derived channel for measuring some physical quantity, for example ‘current’.
  • Make Measurements : Selected channels are displayed. User can make measurements individually for each step or  can sweep in auto mode.
  • Plot and View Plots: Enables user to plot selected parameters. Acquired plots can be selectively displayed or deleted.
  • Save Plots: Data acquired can be save in a spreadsheet.
  • Save Profile : Experiment profile can be saved for repeating the experiment in future. Saved profiles can be loaded from “Load Profile” tab.

Example : Diode IV Characteristics Experiment

For this experiment one needs the following…

  • A variable voltage source : Needs to be swept from Voltage A to  B (say from 0V to 5V)
  • Current Monitoring : Needs to be read for every value of Voltage
  • Plotting and analytics :  Tools to plot the parameters and save data

Schematic Circuit diagram:

diode IV

CH3 monitors the voltage drop across the diode. PV1 is varied in steps, and for each step the current is calculated from the difference between voltages at PV1 and CH3, and the known value of the resistor. For example for 1K resistor, current through the diode is given by

I = (PV1-CH3)/1K

Procedure :

Step 1. Connect Fossasia PSLab to the pc. Connect the components –  Diode from CH3 to Ground and  1k resistor from PV1 to CH3

Step 2. From the terminal Run

Experiments

The App-window will pop-up. Click on ‘Design your own Experiment’ button to get the experiment designer GUI.

experiment designer2

Step 3: Select channels

Sweep Channel PV1 – Sweep from 0.00V -5.00V in 200 steps

Read-back Channel CH3 – for monitoring voltage across the diode

Derived Channel – To measure Current. Type the equation to calculate the current,   (PV1()-CH3())/1000

Step 4. Click on Prepare Experiment‘ to get measurements screen. Click on ‘Evaluate All Rows‘ to make the measurements.

Experiment designer3

Step 5. Select the required columns and click on Plot Selected Columns‘, a message window will pop-up, here user can select the Axes for plotting the graph. On clicking  ‘Plot‘, view plots screen will be displayed.

plotsdiodeiv

One can repeat the experiment and plot multiple curves and save them in a spreadsheet. Acquired plots can be selectively displayed or deleted.

Step 6. The entire design ( Experiment Profile)  of the experiment can be saved for repeating the experiment in future. Saved profiles can be loaded from “Load Profile” tab.

experiment designer profile
This is a very important value add to PSLab Apps. It has enabled PSLab to reach out and help users, who do not have any background in programming. Now ‘designing your own experiments’ has become super easy 🙂 🙂 🙂

PSLab Communication Function Calls

Prerequisite reading:

Communicating with Pocket Science Lab via USB and capturing and plotting sine waves

Interfacing with the hardware of PSLab, fetching the data and plotting it is very simple and straight forward. Various sensors can be connected to PSLab and data can be fetched with a simple python code as shown in the following example…

>>> from PSL import sciencelab
>>> I = sciencelab.connect()     # Initializing: Returns None if device isn't found. The initialization process connects to tty device and loads calibration values.
# An example function that measures voltage present at the specified analog input
>>> print I.get_average_voltage('CH1')
# An example to capture and plot data
>>> I.set_gain('CH1', 3) # set input CH1 to +/-4V range 
>>> I.set_sine1(1000) # generate 1kHz sine wave on output W1 
>>> x,y = I.capture1('CH1', 1000, 10) # digitize CH1 1000 times, with 10 usec interval 
>>> plot(x,y) 
>>> show()
# An example function to get data from magnetometer sensor connected to PSLab
>>> from PSL.SENSORS import HMC5883L #A 3-axis magnetometer >>> M = HMC5883L.connect() >>> Gx,Gy,Gz = M.getRaw() 

The module sciencelab.py contains all the functions required for communicating with PSLab hardware. It also contains some utility functions. The class ScienceLab() contains methods that can be used to interact with the PSLab.

After initiating this class, all the features built into the device can be accessed  using various function calls.


Capture1 : for capturing one trace

capture1(ch, ns, tg)

Arguments

  • ch  : Channel to select as input. [‘CH1′..’CH3′,’SEN’]
  • ns  :  Number of samples to fetch. Maximum 10000
  • tg   :  Time gap between samples in microseconds
#Example >>> x,y = I.capture1('CH1', 1000, 10) # digitize CH1 1000 times, with 10 usec interval

Returns : Arrays X(timestamps),Y(Corresponding Voltage values)


Capture2 : for capturing two traces

capture2(ns, tg, TraceOneRemap='CH1')

Arguments

  • ns :  Number of samples to fetch. Maximum 5000
  • tg  :  Time gap between samples in microseconds
  • TraceOneRemap :   Choose the analogue input for channel 1 (Like MIC OR SEN). It is connected to CH1 by default. Channel 2 always reads CH2.
#Example 
>>> x,y1,y2 = I.capture2(1600,1.75,'CH1') # digitize CH1 and CH2, 1600 times, with 1.75 usec interval

Returns: Arrays X(timestamps),Y1(Voltage at CH1),Y2(Voltage at CH2)


Capture4 : for capturing four taces

capture4(ns, tg, TraceOneRemap='CH1')

Arguments

  • ns:   Number of samples to fetch. Maximum 2500
  • tg :   Time gap between samples in microseconds. Minimum 1.75uS
  • TraceOneRemap :   Choose the analogue input for channel 1 (Like MIC OR SEN). It is connected to CH1 by default. Channel 2 always reads CH2, channel 3 always reads CH3 and MIC is channel 4 (CH4)
#Example
>>> x,y1,y2,y3,y4 = I.capture4(800,1.75) # digitize CH1-CH4, 800 times, with 1.75 usec interval

Returns: Arrays X(timestamps),Y1(Voltage at CH1),Y2(Voltage at CH2),Y3(Voltage at CH3),Y4(Voltage at CH4)


Capture_multiple : for capturing multiple traces

capture_multiple(samples, tg, *args)

Arguments

  • samples:   Number of samples to fetch. Maximum 10000/(total specified channels)
  • tg :   Time gap between samples in microseconds.
  • *args :   channel names
# Example 
>>> from pylab import * 
>>> I=interface.Interface() 
>>> x,y1,y2,y3,y4 = I.capture_multiple(800,1.75,'CH1','CH2','MIC','SEN') 
>>> plot(x,y1) 
>>> plot(x,y2) 
>>> plot(x,y3) 
>>> plot(x,y4) 
>>> show()

Returns: Arrays X(timestamps),Y1,Y2 …


Capture_fullspeed : fetches oscilloscope traces from a single oscilloscope channel at a maximum speed of 2MSPS

capture_fullspeed(chan, amples, tg, *args)

Arguments

  • chan:   channel name ‘CH1’ / ‘CH2’ … ‘SEN’
  • tg :   Time gap between samples in microseconds. minimum 0.5uS
  • *args :   specify if SQR1 must be toggled right before capturing. ‘SET_LOW’ will set it to 0V, ‘SET_HIGH’ will set it to 5V. if no arguments are specified, a regular capture will be executed.
# Example
>>> from pylab import *
>>> I=interface.Interface()
>>> x,y = I.capture_fullspeed('CH1',2000,1)
>>> plot(x,y)               
>>> show()

Returns: timestamp array ,voltage_value array


Set_gain : Set the gain of selected PGA

set_gain(channel, gain)

Arguments

  • channel:   ‘CH1’ , ‘CH2’
  • gain :   (0-7) -> (1x,2x,4x,5x,8x,10x,16x,32x)

Note: The gain value applied to a channel will result in better resolution for small amplitude signals.

# Example
>>> I.set_gain('CH1',7)  #gain set to 32x on CH1


Get_average_voltage : Return the voltage on the selected channel
get_average_voltage(channel_name, **kwargs)
Arguments

  • channel_name:    ‘CH1’,’CH2’,’CH3’, ‘MIC’,’IN1’,’SEN’
  • **kwargs :   Samples to average can be specified. eg. samples=100 will average a hundred readings
# Example 
>>> print I.get_average_voltage('CH4')
1.002

Get_freq : Frequency measurement on IDx. Measures time taken for 16 rising edges of input signal. returns the frequency in Hertz

get_average_voltage(channel='Fin', timeout=0.1)
Arguments

  • channel :    The input to measure frequency from. ‘ID1’ , ‘ID2’, ‘ID3’, ‘ID4’, ‘Fin’
  • timeout :   This is a blocking call which will wait for one full wavelength before returning the calculated frequency. Use the timeout option if you’re unsure of the input signal. returns 0 if timed out
# Example
>>> I.sqr1(4000,25)
>>> print I.get_freq('ID1')
4000.0

Return float: frequency


Get_states : Gets the state of the digital inputs. returns dictionary with keys ‘ID1’,’ID2’,’ID3’,’ID4’
get_states()
#Example
>>> print get_states()
{'ID1': True, 'ID2': True, 'ID3': True, 'ID4': False}

Get_state : Returns the logic level on the specified input (ID1,ID2,ID3, or ID4)
get_state(input_id)
Arguments

  • input_id :    The input channel ‘ID1’ -> state of ID1 ‘ID4’ -> state of ID4
#Example
>>> print I.get_state(I.ID1)
False

Set_state : Set the logic level on digital outputs SQR1,SQR2,SQR3,SQR4
set_state(**kwargs)
Arguments

  • **kwargs :    SQR1,SQR2,SQR3,SQR4 states(0 or 1)
#Example
>>> I.set_state(SQR1=1, SQR2=0) #sets SQR1 HIGH, SQR2 LOw, but leave SQR3,SQR4 untouched.


 

Communicating with Pocket Science Lab via USB and capturing and plotting sine waves

Design of PSLab combines the flexibility of Python programming language and the real-time measurement capability of micro-controllers.

PSLab, with its simple and open architecture allows users to use the tool for various measurements and to develop new experiments with simple functions written in python.

PSLab is interfaced and powered by USB port of the computer. For connecting external signals it has several input/output terminals as shown in the figure.

pslabdesign

Interfacing with the real world

Connecting to PSLab is as simple and straight forward as this…

>>> from PSL import sciencelab
>>> I = sciencelab.connect()     #Returns None if device isn't found
# An example function that measures voltage present at the specified analog input
>>> print I.get_average_voltage('CH1')

Various sensors can be connected to PSLab and data can be fetched with a simple python code as shown below…

>>> from PSL.SENSORS import HMC5883L #A 3-axis magnetometer
>>> M = HMC5883L.connect()
>>> Gx,Gy,Gz = M.getRaw()

The module sciencelab.py contains all the functions required for communicating with PSLab hardware. It also contains some utility functions. The class ScienceLab() contains methods that can be used to interact with the PSLab. The connect() function returns an object of this class if PSLab hardware is detected.

The initialization process does the following

* connects to tty device

* loads calibration values.

>>> from PSL import sciencelab
>>> I = sciencelab.connect()
>>> print I
<PSL.sciencelab.ScienceLab instance at 0x7fe9a7bf0e18>

After initiating this class, its various function calls will allow access to all the features built into the device. Some examples showing the use of few function calls are given below…

Example 1: Capturing and plotting a sine wave

The function call used,

capture1(self,ch,ns,tg,*args,**kwargs)

Arguments

  • ch  : Channel to select as input. [‘CH1′..’CH3′,’SEN’]
  • ns  :  Number of samples to fetch. Maximum 10000
  • tg   :  Time gap between samples in microseconds

Example Program

Connect WG1 to CH1 and run the following code.

>>> from pylab import *
>>> from PSL import sciencelab
>>> I=sciencelab.connect()
>>> I.set_gain('CH1', 3) # set input CH1 to +/-4V range
>>> I.set_sine1(1000) # generate 1kHz sine wave on output W1
>>> x,y = I.capture1('CH1', 1000, 10) # digitize CH1 1000 times, with 10 usec interval
>>> plot(x,y)
>>> show()

For running the script in IDE, one should define source code encoding, add this to the top of your script:

# -*- coding: utf-8 -*-

The output of the program is here…

sine1

Example 2 : Capturing two sine waves and plotting

The function call used,

capture2(self,ns,tg,TraceOneRemap='CH1')

Arguments

  • ns :  Number of samples to fetch. Maximum 5000
  • tg  :  Time gap between samples in microseconds
  • TraceOneRemap :   Choose the analogue input for channel 1 (Like MIC OR SEN). It is connected to CH1 by default. Channel 2 always reads CH2.

Example Program

Connect WG1 to CH1, WG2 to CH2 and run the following code.

# -*- coding: utf-8 -*-

from pylab import *
from PSL import sciencelab
I=sciencelab.connect()
I.set_gain('CH1', 2) # set input CH1 to +/-4V range
I.set_gain('CH2', 3) # set input CH2 to +/-4V range
I.set_sine1(1000) # generate 1kHz sine wave on output W1
I.set_sine2(1000) # generate 1kHz sine wave on output W2

x,y1,y2 = I.capture2(1600,1.75,'CH1') 
plot(x,y1) #Plot of analog input CH1
plot(x,y2) #plot of analog input CH2
show()

The output of the program is here…sine2

Example 3 : Capturing four traces and plotting

The function call used,

capture4(self,ns,tg,TraceOneRemap='CH1')

Arguments

  • ns:   Number of samples to fetch. Maximum 2500
  • tg :   Time gap between samples in microseconds. Minimum 1.75uS
  • TraceOneRemap :   Choose the analogue input for channel 1 (Like MIC OR SEN). It is connected to CH1 by default. Channel 2 always reads CH2.

Example Program

Connect WG1 to CH1, WG2 to CH2, SQR1 to CH3 and transducer mic to MIC (CH4) and run the following code.

# -*- coding: utf-8 -*-

from pylab import *
from PSL import sciencelab
I=sciencelab.connect()
I.set_gain('CH1', 2) # set input CH1 to +/-4V range
I.set_gain('CH2', 3) # set input CH2 to +/-4V range
I.set_sine1(1000) # generate 1kHz sine wave on output W1
I.set_sine2(1000) # generate 1kHz sine wave on output W2
I.sqr1(2000,duty_cycle=50) # generate 1kHz square wave on output SQR1

x,y1,y2,y3,y4 = I.capture4(800,1.75)
plot(x,y1) #Plot of analog input CH1
plot(x,y2) #plot of analog input CH2
plot(x,y3) #plot of analog input CH3
plot(x,y4) #plot of analog input CH4 : MIC
show()

The output of the program is here…waves

Next To Do for GSoC-16

A detailed User manual and programmers manual with description of all function calls. ( Work in progress 🙂  )

Read:
  1. Post about installing PSLab
  2. PSLab and ExpEYES and GSoC-16 work

Science Hack Day Belgaum India 2016

Announcing Science Hack Day Belgaum India – 2016

We are excited to announce our 1st Science Hack Day India. The event will take place on 22-23 October 2016 at Belgaum, a small city surrounded by some splendid nature, in Karnataka State of India.

We welcome you all to join us at SHD Belgaum. Let’s collaborate, learn, hack, build cool stuff and have lots of fun.

Registration is now open at eventbrite.

For more announcements follow us on…

facebooktwitter

What is Science Hack Day?

Science Hack Day is a two-day event where anyone excited about making weird, silly or serious things with science comes together in the same physical space to see what they can prototype within 30 consecutive hours. Designers, developers, scientists and anyone who is excited about making things with science are welcome to attend – no experience in science or hacking is necessary, just an insatiable curiosity.

The mission of Science Hack Day is to get excited and make things with science! People organically form multidisciplinary teams over the course of a weekend: particle physicists team up with designers, marketers join forces with open source rocket scientists, writers collaborate with molecular biologists, and developers partner with school kids. By collaborating on focused tasks during this short period, small groups of hackers are capable of producing remarkable results.

Venue

We have an amazing place called Sankalp Bhumi  Farm Resort for this event. It was once an abandoned quarry,  today natures glory restored. The resort resembles an enchanting oasis, with a thick set of trees, sprawling lawns, and a large lagoon surrounded by picturesque expansive rock walls as backdrop.

5

Tentative Program

Day 1:

09:00 Arrive, check-in, eat breakfast (provided)
10:00 Welcome, introductions
10:30 Hacking begins!
10:45 Lightning talks
12:00 Lunch (provided)
13:00 Hacking continues
18:00 Door closes

Day 2:

09:00 Doors open, breakfast (provided)
12:00 Lunch (provided)
13:30 Hacking stops
14:00 Hack demos begin! (Typically 2-3 minutes per demo)
16:00 Winning teams announced & given awards/medals

Science Workshops

Along with hacking we also have Science Workshops for kids. Workshops will run parallel to the SHD. We will be making amazing science toys and solar lanterns 🙂

Organisers:

FOSSASIA India Team.

Praveen Patil, Hong Phuc Dang, Rahul Khanolkar

Website: http://sciencehack.in

Features and Controls of Pocket Science Lab

Prerequisite reading:

PSLab Code Repository and Installation

PSLab is equipped with array of useful control and measurement tools. This tiny but powerful Pocket Science Lab enables you to perform various experiments and study a wide range of phenomena.

Some of the important applications of PSLab include a 4-channel oscilloscope, sine/triangle/square waveform generators, a frequency counter, a logic analyser and also several programmable current and voltage sources.

Add-on boards, both wired as well as wireless(NRF+MCU), enable measurement of physical parameters ranging from acceleration and angular velocity, to luminous intensity and Passive Infra-red. (Work under progress…)

As a reference for digital instruments a 12-MHz Crystal is chosen and a 3.3V voltage regulator is chosen for the analogue instruments. The device is then calibrated against professional instruments in order to squeeze out maximum performance.

Python based communication library and experiment specific PyQt4 based GUI’s make PSLab a must have tool for programmers, hobbyists, science and engineering teachers and also students.

PSLab is interfaced and powered by USB port of the computer. For connecting external signals it has several input/output terminals as shown in the figure.

pslabdesign
New panel design for PSLab

psl2

Feature list for the acquisition and control :

  • The most important feature of PSLab is a 4-channel oscilloscope which can monitor analog inputs at maximum of 2 million samples per second. Includes the usual controls such as triggering, and gain selection. Uses Python-Scipy for curve fitting.
oscilloscope
PSLab Oscilloscope

 

 

Waveform Generators

  • W1 : 5Hz – 5KHz arbitrary waveform generator. Manual amplitude control up to +/-3Volts
  • W2 : 5Hz – 5KHz arbitrary waveform generator. Amplitude of +/-3Volts. Attenuable via software
  • PWM : There are four phase correlated PWM outputs with maximum frequency 32MHz, 15nano second duty cycle, and phase difference control.

Measurement Functions

  • Frequency counter tested up to 16 MHz.
  • Capacitance Measurement. pF to uF range
  • PSLab has several 12-bit Analog inputs (function as voltmeters) with programmable gains, and maximum ranges varying from +/-5mV to +/-16V.

Voltage and Current Sources

  • 12-bit Constant Current source. Maximum current 3.3mA [subject to load resistance].
  • PSLab has three 12-bit Programmable voltage sources/ +/-3.3V,+/-5V,0-3V . (PV1, PV2, PV3)
controls
Main Control Panel

Other useful tools

  • 4MHz, 4-channel Logic analyzer with 15nS resolution.Voltage and Current Sources
  • SPI,I2C,UART outputs that can be configured and controlled entirely through Python functions. (Work in progress…)
  • On-board 2.4GHz transceiver for wireless data acquisition. (Work in progress..)
  • Graphical Interfaces for Oscilloscope, Logic Analyser, streaming data, wireless acquisition, and several experiments developed that use a common framework which drastically reduces code required to incorporate control and plotting widgets.
  • PSLab also has space for an ESP-12 module for WiFi access with access point / station mode.

Screen-shots of GUI apps.

advanced-controls
Advanced Controls with Oscilloscope
wirelesssensordataloger
Wireless Sensors ( Work in progress…)
logicanalyzer
Logic Analyzer

With all these features PSLab is taking a good shape and I see it as a potential tool that can change the way we teach and learn science. 🙂 🙂

 

PSLab Code Repository and Installation

PSLab  is a new addition to FOSSASIA Science Lab. This tiny pocket science lab  provides  an array of necessary equipments for doing science and engineering experiments. It can function like an oscilloscope, waveform generator, frequency counter, programmable voltage and current source and also as a data logger.

pslabdesign
New Front Panel Design
psl2
Size:62mmx78mmx13mm

The control and measurement functions are written in Python programming language. Pyqtgraph is used for plotting library. We are now working on Qt based GUI applications for various experiments.

The following are the code repositories of PSLab.

Installation

To install PSLab on Debian based Gnu/Linux system, the following dependencies must be installed.

Dependencies
============
PyQt 4.7+, PySide, or PyQt5
python 2.6, 2.7, or 3.x
NumPy, Scipy
pyqt4-dev-tools          #for pyuic4
Pyqtgraph                #Plotting library
pyopengl and qt-opengl   #for 3D graphics
iPython-qtconsole        #optional
Now clone both the repositories pslab-apps and pslab .

Libraries must be installed in the following order

1. pslab-apps

2. pslab

To install, cd into the directories

$ cd <SOURCE_DIR>

and run the following (for both the repos)

$ sudo make clean
$ sudo make 

$ sudo make install

Now you are ready with the PSLab software on your machine 🙂

For the main GUI (Control panel), you can run Experiments from the terminal.

$ Experiments

If the device is not connected the following splash screen will be displayed.

SplashNotConnected
Device not connected

After clicking OK, you will get the control panel with menus for Experiments, Controls, Advanced Controls and Help etc. (Experiments can not be accessed unless the device is connected)

controlPanelNotConnected

The splash screen and the control panel, when PSLab is connected to the pc.

SplashScreen
PSLab connected
controlpanel
Control Panel – Main GUI

From this control panel one can access controls, help files and various experiments through independent GUI’s written for each experiment.

You can help
------------

Please report a bug/install errors here 
Your suggestions to improve PSLab are welcome :)

What Next:

We are now working on a general purpose Experimental designer. This will allow selecting controls and channels and then generate a spread sheet. The columns from this spreadsheet can be selected and plotted.

 

New Tools and Sensors for FOSSASIA PSLab and ExpEYES

ExpEYES: Open Source Science Lab’ is a project FOSSASIA is supporting since 2014. As a part of GSoC-14 and GSoC-15 we started actively developing Pocket Science Lab for open science education. The objective is to make create the most affordable open source pocket lab which can help millions of students and citizen scientists all over the world to  learn science by exploring and experimenting.

We are currently working on  adding new tools/sensors and also  developing a new lab interface with higher capabilities to be added to FOSSASIA Science Lab. My goal for this year’s project is to add new experiments to the ExpEYES library. I also started working on new lab interface.

Here is my kitchen converted to a work space, my GSoC Lab:)

Linear Air track for mechanics experiments, super-critical dryer which uses PSLab for temperature control and monitoring with other instruments.

In the month of May-16, I spent few days at IUAC – Inter University Accelerator Centre, New Delhi, to work with Dr. Ajith Kumar ( Inventor of Expeyes). The time spent at IUAC was most useful as we got help and inputs from many people at IUAC and also the participant teachers of ExpEYES training programme. We designed some new experiments to be done with ExpEYES. Planned improvements in Mechanics experiments especially the experiments on linear air track. We also started working on the new lab interface. Thanks to Jithin B.P. for helping us out with all the development. With the continuous collective efforts now we have a new lab interface. “PSLab: Pocket Science Lab from FOSSASIA”. Here I am trying to give all the details of the equipment and the development done so far and the things planned for next couple of months.


PSLab: Pocket Science Lab from FOSSASIA

Size of PSLab is 62mmx78mmx13mm. The front panel will be slightly different than the one in the picture. It will have little extra portion in the top right corner to accommodative 90 degree connector pins. something like this.pslab
We will finalize the front panel design in a week and get the panels screen printed. The sample kits will be sent to my mentors for testing and suggestions.)

Main Features and GUI’s

PSLab can function like an oscilloscope, data logger, waveform generator, frequency counter, programmable voltage source etc. It can be plugged in to USB port of PC or SBC’s like Raspberry Pi. PSLab has:

  • 2 variable sine waves
  • 4 programmable  square wave generators
  • 3 programmable voltage sources
  • Programmable constant current source
  • 4 channels for fetching data
  • Sensor input
  • Berg Strip sockets  etc…

We are also working on to add wireless sensor interface. This will enable PSLab in accessing various sensors using a wireless module.

PSLab Code repository , Installation and Communicating with PSLab

All the programs are written in Python. PyQt is used for GUI designing and Pyqtgraph is used for plotting library. I have created two repositories  for PSLab

  • https://github.com/fossasia/pslab-apps: GUI programs and templates for various experiments. (Depends on python-pyqtgraph (>=0.9.10), python-qt4 (>=4.10), ipython(>=1.2), ipython-qtconsole(>=1.2)

In addition to the above development work we also conducted a few demonstration sessions in science and engineering colleges at Belgaum, India. The feedback from teachers and students in improving the kit  is really helpful in modifying the GUI’s for better user experience.

Next Steps/To Do

  • Add new experiments to PSLab
  • Complete Voltammetry module for ExpEYES
  • Complete Unified GUI for all  Mechanics Experiments using ExpEYES
  • Documentation for PSLab

We are  getting about 25 PSLab  kits ready in the first batch by the end of this month. Thanks to funding from GSoC-15.) Need to work on the [email protected] website. Next immediate plan is to get about 50-100 kits ready and update the website with all the information and user manuals before FOSSASIA-17. I am also working on a plan to reach-out to  maximum number of science and engineering students who will definitely get benefit from PSLab.)

A low-cost laboratory for everyone: Sensor Plug-ins for ExpEYES to measure temperature, pressure, humidity, wind speed, acceleration, tilt angle and magnetic field

Working on ExpEYES in the last few months has been an amazing journey and I am gratful of the support of Mario Behling, Hong Phuc Dang and Andre Rebentisch at FOSSASIA. I had a lot of learning adventures with experimenting and exploring with new ideas to build sensor plug-ins for ExpEYES. There were some moments which were disappointing and there were some other moments which brought the joy of creating sensor plug-ins, add-on devices and GUI improvements for ExpEYES.

My GSoC Gallery of Sensors and Devices: Here are all the sensors I played with for PSLab..

The complete list of sensor plug-ins developed is available at http://gnovi.edublogs.org/2015/08/21/gsoc-2015-with-fossasia-list-of-sensor-plug-ins-developed-for-expeyes/

Sensor Plugins for ExpEYES

The aim of my project is to develop new Sensor Plug-ins for ExpEYES to measure a variety of parameters like temperature, pressure, humidity, wind speed, acceleration, tilt angle, magnetic field etc. and to provide low-cost open source laboratory equipment for students and citizien scientists all over the world.

We are enhancing the scope of ExpEYES for using it to perform several new experiments. Developing a low-cost stand alone data acquisition system that can be used for weather monitoring or environmental studies is another objective of our project.

I am happy to see that the things have taken good shape with additional gas sensors added which were not included in the initial plan and we have almost achieved all the objectives of the project, except for some difficulties in calibrating sensor outputs and documentation. This issue will be solved in a couple of days.

Experimenting with different sensors in my kitchen laboratory

I started exploring and experimenting with different sensors. After doing preliminary studies I procured analog and a few digital sensors for measuring weather parameters like temperature, relative humidity and barometric pressure. A few other sensors like low cost piezoelectric sensor, accelerometer ADXL-335, Hall effect magnetic sensor, Gyro-module etc were also added to my kitchen laboratory. We then decided to add gas sensors for detecting Carbon Monoxide, LPG and Methane.

With this development ExpEYES can now be used for pollution monitoring and also in safety systems in Physics/chemistry laboratory. The work on the low-cost Dust Sensor is under progress.

Challenges, Data Sheet, GUI programs

I had to spend a lot of time in getting the sensor components, studying their data sheets, soldering and setting them up with ExpEYES. And then little time in writing GUI Programs. I started working almost 8 to 10 hours every evening after college hours (sometimes whole night) and now things have taken good shape.

Thanks to my mentor at FOSSASIA for pushing me, sometimes with strict words. I could add many new sensor plug-ins to ExpEYES and now I will also be working on Light sensors so that the Pocket Science Lab can be used in optics. With these new sensor plug-ins one can replace many costly devices from Physics, Chemistry, Biology and also Geology Lab.

What’s next? My Plan for next steps

  • Calibration of sensor data

  • Prototyping stand-alone weather station

  • Pushing data to Loklak server

  • Work on [email protected] website

  • Fossasia Live Cd based on Lubuntu with ExpEYES and other educational softwares

  • Set-up Documentation for possible science experiments with the sensor plug-ins and low-cost, open source apparatus