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

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.)

Participate in FOSSASIA Summit 2016 in Science Center Singapore, March 18th-20th

Please join us at FOSSASIA 2016 in Singapore, the premier Open Technology event in Asia.

The event will take place from March 18-20 at the Singapore Science Center and already on 17th March the pgDay Asia conference is part of the pre-event activities.

The FOSSASIA weekend from Friday to Sunday is dedicated to the “Internet of Things and Me” covering open technologies and software that make todays connected devices run. In workshops kids can start learning with the Pocket Science Lab. In the Science Hack track attendees will learn how to participate in the Citizen Science community. Please:

More than 120 speakers from Asia and around the world will join the event from communities and companies such as Google, RedHat, and Github. There will be talks and hands on workshops on topics including:

  • Open Hardware, Makers, Internet of Things
  • Open Source Software, Data and Free Knowledge
  • DevOps, Docker, Programming languages, Python, Go, and more
  • Science Hacks and Open Design
  • Tech and Science for Kids

Info on the FOSSASIA Summit 2016 at the Event Website

Read the Call for Speakers here.

Join the FOSSASIA Meetup Group in Singapore and reserve your spot in workshops as soon as they are announced.

Follow us on Twitter.

Check out the photos from last year on Flickr.

Kids Coding with FOSSASIA and Google Code-In

After the successful Google Summer of Code we are very happy and honored to participate for the second year in Google Code-In. The contest introduces pre-university students (ages 13-17) to open source software development and runs from December 7 2015 until January 25, 2016. Learn more here.

Because Google Code-in is often the first experience many students have with open source, the contest is designed to make it easy for students to jump right in. Open source organizations chosen by Google provide a list of tasks for students to work on during the seven week contest period. A unique part of the contest is that each task has mentors from the organization assigned should students have questions or need help along the way.

Google Code-In FOSSASIA

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