Experiments
About
Reources
The origins this project can be traced back to the developments in the Particle Accelerator Control systems and the Data Acquisition Systems at Inter-University Accelerator Centre (started as Nuclear Science Centre in 1984). The Control System was initially running on a DEC PDP11 computer and the Data Acquisition System on two MicroVAX systems. Both were expensive to maintain.
During the second half of 1980s the IBM PC compatible computers started appearing in India. The documented ISA bus of the IBM PC design allowed addition of hardware devices to it. Leveraging on these features, a PC based control system was developed for the Pelletron (16 MV Tandem Van de Graff accelerator), and it became operational in 1988. The operating system was MSDOS. This was followed by the development of hardware modules (following CAMAC standard) required for control system.
During 1990s, a plan to add a LINAC to the Pelletron started, that would require the Control System to support multiple operator consoles. In 1994, while searching for a multi-user operating system I happened to come across the GNU/Linux operating system and the Free Software movement. Within two years we developed control and data acquisition systems on PCs running GNU/Linux, entirely by using Free Software tools. Experiments using the particle accelerator utilizes computers for data acquisition and analysis. The users coming from the universities were not familiar with such systems. The availability of the Free Software tools, including the GNU/Linux operating system, and our expertise in electronics resulted in exploring the possibilities of making a low cost equipment to perform computer interfaced experiments for teaching science.
Developing a low cost data acquisition and control system to perform simple experiments was desirable but connecting extra hardware using ISA bus required opening of the computer cabinet. We decided to use the Parallel port (used by printers at that time) and developed the first version of a device in 2005. The software was initially developed using the Turbo-C compiler and later on ported to GNU/Linux. A device driver performed the real time measurements, like sampling a waveform.
The first setup looked like THIS
The details of it are available on the IUAC website. Ajith Kumar B.P. and V V V Satyanarayana, IUAC, initiated the PHOENIX project by designing a parallel port based interface. Other people from IUAC who has contributed to this project are mainly Jimson Sacharias, Kundan Singh, Parmanand Singh, Deepak Munda and S Venkataramanan. The first teacher training program was conducted in 2005, and IUAC continue to conduct one program every six months.
Since the project is Open Sourced, several others outside IUAC also contributed. One important development happened at this time was switching to Python programming language, which was triggered by the contributions from Pramode C E.
George Khaznadar (School teacher and Debian Developer), from France made several contributions to the software and also made it a part of the Debian and Ubuntu repositories. Later on he deployed around 40 pieces of the Serial port version in the school where he worked.
The parallel ports were becoming obsolete and the product was approaching a dead end. Fortunately the experience in playing with the Atmega-8 micro-controller opened a new channel. Free Software tools were available to program Atmega-8 (avr-gcc compiler) and the code could be uploaded via few wires connected to the PC parallel port.
A new design was done by implementing a kind of ‘server’ program running on the micro-controller and listening to the commands coming over a serial port. The command triggers some activity and the results are send back over the serial port. This design confines all the real-time measurements to the micro-controller side. The Computer side only sends the commands and processes the replies, as per the user requirement. The PC side code was ported to Python. The hardware was powered by a 9 volts DC adapter.
Later on when the Serial ports also started getting obsolete, we added some USB to Serial converter solutions. After several prototypes finally the device looked like THIS
More information available on the IUAC website
The DC adapter available in those days were linear designs using step down transformer, rectifier and filter. When the input supply is very low, the regulated DC powering the micro-controller was affected. To solve these problems, we generated all the required DC supplies, +5V, +9V and -9V from the 5V supply from the USB, using doubler and inverter circuits. The Analog resolution was improved using separate 12 bit ADCs. This work was completed in 2011.
Electronics For You article about the first version of ExpEYES
This development work was triggered by a request to reduce the cost, from an official of the HRD Ministry, who was involved in the Aakash tablet project. More details on the Evolution of EpEYES junior
This was the last design done completely at IUAC. Most of these developments were done during the waiting periods of particle accelerator related works. After 2006, the next revision came in 2011 only. After 2012, we spend some amount of time on training teachers and conducting workshops but no new revisions were done. Apart from lack of time, there were some other issues also. The more powerful micro-cotrollers were coming only as SMD packages with very fine pitch, requiring automated systems for fabrication. ExpEYES junior components were selected to use hand soldering.
This was an open source design released to the public, by Jithin B P, and taken up by IUAC. After completing his MSc from IISER Mohali in 2014, he started developing instruments for performing scince experiments. Most of them are released under Open Source licenses. A chronology of his work finally leading to ExpEYES-17 is avaiable on his website
The latest development in this direction is the Android version of the Software.
Ajith Kumar B P
bpajith at gmail dot com
