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<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta content="text/html; charset=utf-8" http-equiv="content-type"/>
<link rel="stylesheet" type="text/css" href="css/menu.css"/>
<title>Evolution of expeyes junior</title>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript" src="js/language.js"></script>
</head>
<body> <a href="index.html"><img src="images/eyes-logo.png" height="100" width="420" alt="eyes logo"/></a>
<div id="mynb">
<ul>
<li><a href="design.html"> <span class="tr">Design</span></a></li>
<li><a href="hardware.html"> <span class="tr">How to Buy</span></a></li>
<li><a href="software.html"> <span class="tr">Software</span></a></li>
<li><a href="android.html"> <span class="tr">Android</span></a></li>
<li><a href="python.html"> <span class="tr">python</span></a></li>
<li><a href="microhope.html"><span class="tr">MicroHOPE</span></a></li>
<li><a href="people.html"> <span class="tr">People</span></a></li>
<li><a href="news.html"><span class="tr">News</span></a></li>
</ul>
</div>
<h2 class="tr title">Evolution of expEYES Junior</h2>
<div id="node-top" class="node-top region nested"> </div>
<p><span class="tr font14">Nov-2011: expEYS was released in Mar-2011
and is doing reasonably well. There was no plan to develop another
version.</span></p>
<p><span class="tr font14">6-Nov-2011 : <a href="http://www.aero.iitb.ac.in/%7Eprabhu/">Prabhu</a>,s
mail ..Looking forward to seeing you at <a href="http://scipy.in/scipyin/2011/talks-cfp/speakers/">SciPy.in
2011</a>.</span></p>
<p><span class="tr font14">4-Dec-2011 : <a href="http://urtalk.kpoint.in/playlist/43/kapsule/gcc-b73217cf-469a-4c52-ad22-e2c40c88bd5d">Gave
a demo</a> of expEYES at Scipy.in 2011</span></p>
<p><span class="tr font14">5-Dec-2011 : Met <a href="http://www.che.iitb.ac.in/online/node/52">Prof.
Kannan Moudgalya</a> and gave a demo expEYES.</span></p>
<p><span class="tr font14">9-Dec-2011 : Prof. Kannan arranged meeting
with N K Sinha, Director of NMEICT project, MHRD. Talked about the
possibility of using expEYES with the Akash tablet PC. Shri Sinha wanted
something costing only few hundred rupees. Also gave a demo at their
committee meeting. Submitted a proposal to NMEICT for some human
resource to conduct expEYES training programs and attended meeting on
26-Dec-11.</span></p>
<p><span class="tr font14">Even though no Android version of expEYES
made, the<strong> idea of a very low cost device</strong> came up. I
decided to explore the options for lowering the cost further. A design
using Atmega328, from Atmel Corp., was made, using built-in 10 bit ADC
and PWM DAC. PCB size reduced to 9mm x6 mm</span></p>
<p><span class="tr font14">29-Dec-11 : PCB sent for fabrication.
</span></p>
<p><span class="tr font14">3-Jan-12 : Sent another version of PCB for
fabrication. To reduce size, it replaced TC7660 with TC1240A
voltage doubler.</span></p>
<p><span class="tr font14">12-Jan-12 : Went back to TC7660 since one
of the TC1240A failed during continuous testing, keeping both versions.</span></p>
<p><span class="tr font14">Tested by writing the required C and Python
programs, like CRO. </span></p>
<p><img src="images/proto-trial2.jpg" style="width: 450px; height: 232px;" alt="a trial"/></p>
<p><span class="tr font14">Started looking for micro-controllers with
built-in USB, 12bit ADC and 2k RAM. Found PIC18F2458, from Microchip
Inc., having both. After contacting Microchip, it was realised that the
built-in USB cannot be used simultaneously with the real-time
measurements required. Changed to PIC18F25KA80 + MCP2200 combination.
Vinod & Pramode did ADC & UART testing of PIC18F2458. Almost
decided to go for a PIC controller.</span></p>
<p><span class="tr font14">29-Jan-12 : Sent the PIC based PCB for
fabrication. The memory bank switching found too slow for C code filling
large arrays. The uC architecture doesn't look very C compiler
friendly. Searched, with inputs from Pramode CE, for a 16 bit
version satisfying the requirements, found PIC24FV32KA302. Supported by
gcc.</span></p>
<p><span class="tr font14">31-Jan-12 : Attended the Technical Training
Seminar by Microchip. Fortunately Microchip released development tools,
MPLABX, for GNU/Linux also.</span></p>
<p><span class="tr font14">9-Feb-12 : Sent PIC24 uC based PCB for
fabrication.</span></p>
<p><span class="tr font14">18-Feb-12 : Received PICKIT3 programmer and
PIC24FV32KA302 chips. Surface mount package was ordered by mistake,
instead of DIP, but tested them using PICKIT3 somehow. Started testing
the PCB from the beginning of Mar-12, facing problems mostly due to lack
of familiarity with PIC uCs. Thanks to the cooperation from Microchip
things are getting sorted out. Solving a UART error took days, to
realize that the watchdog timer is enabled by default.</span></p>
<p><span class="tr font14">13-Mar-12: Transmitted 1 million blocks, of
256bytes, from uC to PC without any error. ADC seems to be at par
with the MCP3208 used in expEYES.</span></p>
<p><span class="tr font14">20-Mar-12 : C language code failed to meet
the 100 ksamples/sec rate for ADC blockread. Started learning
PIC24 assembly language, great help from the <a href="http://my.safaribooksonline.com/book/electrical-engineering/semiconductor-technology/9781584505839/introduction-to-the-pic24-microcontroller-family/ch03lev1sec5#X2ludGVybmFsX0ZsYXNoUmVhZGVyP3htbGlkPTk3ODE1ODQ1MDU4MzkvNzg=">online
book</a> by Robert Reese, Bryan Jones and J. W. Bruce. </span></p>
<p><span class="tr font14">26-Mar-12: With assembler code ADC
blockread giving 250 ksample/sec sampling rate, Timer1 ISR is used.
Tested single channel block reads by capturing and fitting sine wave.</span></p>
<p><span class="tr font14">1-Apr-2012: Received a mail from Myra
Vanlnwegen, education coordinator for the <a href="http://www.raspberrypi.org/">Raspberry
Pi</a> Foundation, asking whether expEYES work with Raspberry Pi.
Requested her to send one Rpi board.</span></p>
<p><span class="tr font14">5-Apr-12 : Time measurement routines are
almost done. A numbering scheme is worked out to make the functions more
generic. A CRO program is running now.</span></p>
<p><span class="tr font14">7-Apr-12: Again some changes in hardware.
Decided to provide only one amplifier. A digital output other that SQRs,
all using a CMOS buffer IC. Introduced TC1240A after some continuous
testing.</span></p>
<p><span class="tr font14">8-Apr-12: Having trouble with Charge Time
Measurement Unit of PIC micro. A = 5.5 uA, 48.6 uA & 451 uA in 3
different ranges, measured using DMM. With 10x CRO probe connected V
=1.25 after feeding 5.5 uA for 10 usecs. Error reported but no
solution yet.</span></p>
<p><span class="tr font14">18-Apr-2012: The Rpi board arrived. Help
for testing came from Alex Bradbury.</span></p>
<p><span class="tr font14">20-Apr-2012: expEYES tested on Rpi.
Everything is fine except a USB error that allows only keyboard or mouse
along with expEYES. Bug report filed.</span></p>
<p><span class="tr font14">1-May-2012: A serial port version of
expEYES has been developed for Rpi. Communication tested between uC and
Rpi. The PCB has been send for fabrication.</span></p>
<p><span class="tr font14">9-May-12: Did several iterations of
prototyping. Added a 1mA constant current source with ON/OFF control.
Firmware almost done. Wrote a CRO program with extra features. Drawings
of the plastic shell given for making the mould. Almost getting ready
for production.</span></p>
<p><span class="tr font14">16-May-12 : expEYES was announced on <a href="http://www.raspberrypi.org/archives/1228">Raspberry
Pi</a> webpage. Getting resonably good feedback and enquiries about
availability. Planning to make USB & Serial version (for Rpi), both
having almost identical layout.</span></p>
<p><span class="tr font14">17-May-12 : Started testing and documenting
experiments for the new model. Modifying firmare and Python code
whereever required. Some modifications are done to the hardware also.
Trying to reach the final PCB at the earliest.</span></p>
<p><span class="tr font14">23-May-12: The first lot of PBCs send for
fabrication, asked the vendor in Delhi to start making some sample
pieces. Stopped work for two weeks, programs at JIT, Coimbatore and NIT,
Calicut.</span></p>
<p><span class="tr font14">7-Jun-2012: Started writing software and
documentation. A CRO program with some extra features was done first. By
end of June several boards were assembled. Some minor changes to the
PCB. The read back of Square waves shifted to the after the buffer.
Series resistors added to A1 and A2 inputs after level shifting. Got the
plastic cabinets.</span></p>
<p><span class="tr font14"><img src="images/proto-trial3.jpg" style="width: 400px; height: 203px;" alt="a trial"/></span></p>
<p><span class="tr font14">1-Jul-2012: Final PCB send for fabrication.</span></p>
<p><span class="tr font14">16-Jul-2012: Units send to Pramode &
Georges, for testing.</span></p>
<p><span class="tr font14">2-Aug-2012: Finished <a href="software.html">Software</a>
and a <a href="http://expeyes.in/Documents/eyesj-a4.pdf">User Manual</a>
describing around 50 experiments are ready. Website update and videos
are pending.</span></p>
<p><span class="tr font14"><a href="http://expeyes.in/articles/55/expeyes-junior">ExpEYES
Junior</a> is ready. Photograph below shows capturing sound from a
Piezo Buzzer.</span></p>
<p><span class="tr font14">20-Aug-2012: First lot of commercial
production started.</span></p>
<p><img src="images/ejphoto.jpg" style="width: 380px; height: 355px;" alt="e.j."/></p>
</body>
</html>
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