Partie interactive du site pédagogique ELECINF344/ELECINF381 de Télécom ParisTech (occurrence 2011).


IRL : firsts tests with the real laser

Real laser

Today we replaced the oscilloscope by the real laser. As expected, it does not exactly work the same way, but our first test with « The Riddle » is not so bad. You can see it on the video below, it is little as we do not have a lot of space in the classroom. You can see that the image is blinking, this is partly due to our code, but also partly due to the camera sync, and the « real » result is cleaner than what can be seen here.

FPGA design

The new design suggested by our teachers has been implemented, except for the FIFO which for the moment does not use the internal RAMs This will normally be done tomorrow. The FIFO, as it is now sometimes, leads to some bugs that we do not really understand yet. We will also investigate those issues tomorrow. Nevertheless, we have a functional design, the one we used tonight to make the video.

Tweet to ILDA

Concerning the way we will display tweets, Sam suggested us to make a smooth horizontal scrolling. Our first idea was to generate a big ILDA image containing the whole tweet on one line, and to clip it at display time, just before sending it to the laser. It seems that is was not the best way to act. So, we are now trying to generate an ILDA animation corresponding to the scrolling with a Python script. We are on our way and we have yet disclosed a few points of intersert to change in our design to make it work soon.

Web interface

The library we mentionned last time (libmicrohttpd) seems to fit quite well with our needs. It is not a complete Web server, but it is enough to make the card serve a static HTML page and a little REST API to get tweets and validate them. The authentication is for the moment very basic it consists in a « secret » token as segment of the URI. It is not very secure, but it is not our priority at the very moment.

IRL: the riddle with a mere oscilloscope!

Yesterday we achieved a new goal : we successfully played an ILDA animation on a mere oscilloscope. We attach a video as an evidence of our performance.

Let’s focus on what we actually did.
We built a program which plays directly an ILDA animation in the ILDA file format. We can set several options directly on the command line such as the time spent per frame and the scaling factor.

We enhanced our code which built an ILDA file from a string or a file. It operates directly on board and is now using an ILDA file per character instead of a SVG file with the whole charset.
We display directly on the board a list of tweets taken from a database and fetched them on the go with the twitter API that we now use in C instead of Python.

The IRL project would be nothing without those huge changes that drew our path since the beginning of the project. And we are proud to announce that we are changing (again) our architecture, and we would like to thank our teachers for their precise suggestions on that topic. In a word we are going to rely on a wishbone bus so as to assure the communication through the entities of the FPGA. In that way, out system will be cleaner plus it will enhance its capabilities.