Pocket Science

Read more about the article Temporally accurate data acquisition via digital communication pathways in PSLab

Temporally accurate data acquisition via digital communication pathways in PSLab

This blog post deals with the importance of using a real-time processor for acquiring time dependent data sets. The PSLab already features an oscilloscope, an instrument capable of high speed voltage measurements with accurate timestamps, and it can be used for monitoring various physical parameters such as acceleration and angular velocity as long as there exists a device that can generate a voltage output corresponding to the parameter being measured.  Such devices are called sensors, and a whole variety of these are available commercially. However, not all sensors provide an analog output that can be input to a regular oscilloscope. Many of the modern sensors use digitally encoded data which has the advantage of data integrity being preserved over long transmission pathways. A commonly used pathway is the I2C data bus, and this blog post will elaborate the challenges faced during continuous data acquisition from a PC, and will explore how a workaround can be managed by moving the complete digital acquisition process to the PSLab hardware in order create a digital equivalent of the analog oscilloscope. Precise timestamps are essential for extracting waveform parameters such as frequency and phase shifts, which can then be used for calculating physics constants such as the value of acceleration due to gravity, precession, and other resonant phenomena. As mentioned before, oscilloscopes are capable of reliably measuring such data as long as the input signal is an analog voltage, and if a digital signal needs to be recorded, a separate implementation similar to the oscilloscope must be designed for digital communication pathways. A question for the reader : Consider a voltmeter capable of making measurements at a maximum rate of one per microsecond. We would like to set it up to take a thousand readings (n=1000) with a fixed time delay(e.g. 2uS) between each successive sample in order to make it digitize an unknown input waveform. In other words, make ourselves a crude oscilloscope. Which equipment would you choose to connect this voltmeter to in order to acquire a dataset? A 3GHz i3 processor powering your favourite operating system, and executing a simple C program that takes n readings in a for loop with a delay_us(2) function call placed inside the loop. A 10MHz microcontroller , also running a minimal C program that acquires readings in fixed intervals. To the uninitiated, faster is better, ergo, the GHz range processor trumps the measly microcontroller. But, we’ve missed a crucial detail here. A regular desktop operating system multitasks between several hundred tasks at a time. Therefore, your little C program might be paused midway in order to respond to a mouse click, or a window resize on any odd chores that the cpu scheduler might feel is more important. The time after which it returns to your program and resumes acquisition is unpredictable, and is most likely of the order of a few milliseconds. The microcontroller on the other hand, is doing one thing, and one thing only. A delay_us(2) means a 2uS delay with an…

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Read more about the article Porting PSLab Libraries – Python to Java

Porting PSLab Libraries – Python to Java

PSLab has existing communication libraries and sensor files in Python which were created during the development of Python Desktop Application. The initial task and challenge was porting this existing code to Java to be used by the Android App. Since, the python libraries also utilized the object oriented model of programming, porting from Python to Java had the similar code structure and organization. Common problems faced while porting from Python to Java The most common problem is explicitly assigning data types to variables in Java since Python manages data types on its own. However, most of the time the data types are quite evident from the context of their use and understanding the purpose of the code can make the task much simpler. Another task was migrating the Python data structures to their corresponding Java counterparts like a List in Python represents an ArrayList in Java, similarly a Dictionary corresponds to a HashMap and so on. Some of the sections of the code uses highly efficient libraries like Numpy and Scipy for some mathematical functions. Finding their corresponding Java counterparts in libraries was a challenge. This was partly solved by using Apache Common Math which is a library dedicated for mathematical functions. Some of the functions were directly implemented using this library and for rest of the portions, the code was written after understanding the structure and function of Numpy methods. While porting the code from Python to Java, some of the steps which we followed: Matching corresponding data-structures The Dictionary in python... Gain_scaling = OrderedDict ([('GAIN_TWOTHIRDS', 0.1875), ('GAIN_ONE', 0.125), ('GAIN_TWO', 0.0625), ('GAIN_FOUR', 0.03125), ('GAIN_EIGHT', 0.015625), ('GAIN_SIXTEEN', 0.0078125)]) ...was mapped to corresponding Java HashMap in the manner given below. A point to be noted here is for adding elements to a HashMap can be done only from a method and not at the time of declaration of HashMap. private HashMap <String,Double> gainScaling = new HashMap <String,Double>(); gainScaling.put("GAIN_TWOTHIRDS",0.1875); gainScaling.put("GAIN_ONE",0.125); gainScaling.put("GAIN_TWO",0.0625); gainScaling.put("GAIN_FOUR",0.03125); gainScaling.put("GAIN_EIGHT",0.015625); gainScaling.put("GAIN_SIXTEEN",0.0078125); Similarly, the List in Python can be  be converted to the corresponding ArrayList in Java. Assigning data types and access modifiers to corresponding variables in Java POWER_ON = 0x01 gain_choices = [RES_500mLx, RES_1000mLx, RES_4000mLx] ain_literal_choices = ['500mLx', '1000mLx', '4000mLx'] scaling = [2, 1, .25] private int POWER_ON = 0x01; public int[] gainChoices = {RES_500mLx,RES_1000mLx,RES_4000mLx}; public String[] gainLiteralChoices = {"500mLx", "1000mLx", "4000mLx"}; public double[] scaling = {2,1,0.25}; Assigning data types and the corresponding access modifiers can get tricky sometimes. So, understanding the code is essential to know whether a variable in limited to the class or needs to be accessed outside the class, whether a variable is int, short, float or double etc. Porting Numpy & Scipy functions to Java using Apache Common Math For example, this piece of code gives the pitch of acceleration. It uses mathematical functions like arc-tan. pitchAcc = np.arctan2(accData[1], accData[2]) * 180 / np.pi The corresponding version of arc-tan in Apache Common Math is used in Java. double pitchAcc = Math.atan2(accelerometerData[1], accelerometerData[2]) * 180 / pi; Porting by writing the code for Numpy and…

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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. Travis 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…

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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 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: 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. 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. Step 5. Select the required columns and click on…

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PSLab Communication Function Calls

Prerequisite reading: https://blog.fossasia.org/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 :…

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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. 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... 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) #…

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Features and Controls of Pocket Science Lab

Prerequisite reading: https://blog.fossasia.org/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. 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.     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) 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. 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. :) :)  

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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. 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. https://github.com/fossasia/pslab  : This repository hosts the Communication library for  PSLab. https://github.com/fossasia/pslab-apps  : This repository is for Qt based GUI programs, widgets and templates for various experiments. 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. 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) The splash screen and the control panel, when PSLab is connected to the pc. 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.  

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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. 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: This repo hosts the python library for PSLab (Communication Library depends on python, python-serial, python-numpy) https://github.com/fossasia/pslab-apps: GUI programs and templates for…

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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 laboratoryI 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 programsI 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 PSLab@Fossasia website Fossasia Live Cd based on Lubuntu with ExpEYES and other…

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