I remember in high school in France, our class only had 2 oscilloscopes and few other electronics equipment, needless to say I did not actually get to use an oscilloscope until I went to university. It would have been nice to be able to play around with oscilloscopes, frequency generators, etc… earlier, but due to budget constraints, this was not possible. Dr Ajith Kumar, a scientist working with the Inter University Accelerator Centre of India, has spent several years working on an ultra low cost electronics lab composed of an oscilloscope and a signal generator to provide students attending schools that cannot afford regular equipments. This learning & experimentation tool is called expEYES, and a prototype was demonstrated last year with the Raspberry Pi. At the end of last year, the final version called expEYES Junior (aka expEYES 2.0) was announced, and is now available to schools and hobbyists in several shops in India and France.
To use the device, simply connect it to a Linux computer / board via USB, install expEYES software (in Ubuntu: apt-get install expeyes), connect some components, and display the waveform on the screen of your computer.
Key features of expEYES Junior include:
- Built-in Signal Generator and 4-channel digital signal oscilloscope.
- 50 documented experiments.
- The kit comes with components used in the experiments.
- USB Powered.
- 12bit analog resolution.
- Sampling frequency – 250 kHZ
- Weight – 60 g.
- Dimensions – 8.6×5.8×1.6 cm
Since expEYES is only one piece of the puzzle to bring costs down, and you’ll also need low cost Linux hardware to display the waveform such as Atom netbooks or the Raspberry Pi. However, for this particular application, low cost tablets are most probably the way to go since they include the display. expEYES together with Aakash2 (Education tablet sponsored by the Indian government) can provide an electronics lab for as low as 3,000 Indian rupees (about $55 US). Watch the demo below to see how the pair works together.
expEYES Junior is open hardware & software (C and Python programming language). That means the schematics, PCB layout, and gerber files are freely available, and if you are a manufacturer, you can reproduced the design and sell it. The hardware is pretty simple with 2 main components: AVR ATMega16 MCU @ 8MHz combined with FT232RL USB UART interface IC.
If you are interested in this device, Ajith gave a 20-minute presentation at FOSS.IN in December 2012, where you’ll learn more about the device. You’ll also learn that although the BoM cost is around $10, it currently costs about $30 because of low production volumes, which means it could easily go below $20 with higher volumes. The sampling frequency is now limited to 250 kHz, which might not be a big issue for educational purpose, but may be a problem for hobbyists, and one way to improve this would be to use an FPGA to handle signals.
You can find further information on expEYES website including hardware and software files, learning materials, and more.