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Venez découvrir et expérimenter avec les sonorités et distortions analogiques bien old school produites par les vieilles technos germanium de l’époque soviétique. Au programme: fabrication maison de pédales et boîtes d’effets, et de synthétiseurs pre-8-bit!

Ce workshop s’adresse tout aussi bien aux débutants souhaitant apprendre à souder avec un schéma simple qu’à des personnes expérimentées voulant essayer leurs propres effets.

MATERIEL
Il y en aura un peu sur place (notamment un carton rempli de circuits soviétiques avec des transistors germanium à récupérer), mais pour être sûr de pouvoir faire ce que vous voulez, amenez:

• des plaques veroboard (photo ci-dessous)
• votre fer à souder
• composants discrets en tous genre: résistances, condensateurs, potentiomètres, …
• piles
• hauts parleurs (amplifiés ou non) et sources sonores (guitares électriques, …)
• connecteurs (jacks, …) à souder
• des appareils électroniques à cannibaliser
• des schémas si vous en avez à proposer. Un peu d’inspiration peut se trouver ici, ici, ici et là (merci à Urs pour les liens ).
• des bières

Pour acheter des composants: vous avez par exemple, sur Paris, ECE (Nation), Selectronic (Nation), RAM (Nation), Electronique Diffusion (Malakoff), en VPC Farnell, …

Veroboard (Wikipedia)

INFOS PRATIQUES
Date: samedi 21 août 2010, de 14:00 à 20:00
Lieu: le Black Box, un hacklab parisien faisant partie du Théâtre de Verre. Adresse: 17 rue de la Chapelle, 75010 Paris. Code: A7398. Métro: Marx Dormoy.

Contact: seb chez tmplab point org

INSCRIPTION
Le Black Box étant underground au point de ne pas avoir de site web (ouuuhhh!), les inscriptions se font en commentant ce post de blog. La participation au workshop est gratuite.

Following up Jeri Ellsworth’s home chip fab:

Building up the metal layers.
She currently uses conductive ink (the same one used to repair PCBs and hand-tune RF microstrip lines). This can be done with a stencil but the reliability and resolution are low. Furthermore, this ink is very expensive.
What is typically done in the industry to build such layers with a high reliability and resolution is a physical vapor deposition process. The physics behind it is simple: you just boil off a metal (typ. aluminium) by heating it (aluminium as a pretty low melting point), and condense it on the (colder) substrate. You make a vacuum to remove impurities, increase the mean free path of the aluminium atoms, and further lower the melting point.
For a good quality deposition, the required level of vacuum is high. The industry uses turbomolecular pumps, which are fast, but also extremely expensive, delicate, fragile (if for some reason the vacuum chamber is brutally open, the pump is irreversibly destroyed) and hard to deal with. However, for slower pumping speed (and therefore more time to make the vacuum), oil diffusion pumps are suitable. They are cheaper and harder to destroy. Some are available from eBay for a few hundred euros.
Both models of pumps do not operate at atmospheric pressure and require a traditional (rotary vane) vacuum pump in series. Several people told me that refrigerator compressors will not work (pressure drop is not low enough + the pump will fail when operated in air for a long time). Air conditioner pumps might do better.
For melting the aluminium, I have seen a design that pumps high currents (around 300A) through a tungsten crucible. While it is very possible to replicate this design (FYI we have a 3.3V 1000A power supply at the lab, otherwise I guess welding stations are fine) any other heating system that can heat a few dozens grams of aluminium to 600-700 degrees in vacuum is OK.
Having this physical vapor deposition system will not only enable metallization of chips in the long term, but also build-up of PCB-like devices on various substrates (glass, soft plastics, …) in the shorter term.

Exposing the photoresist with high precision.
The industry typically uses a special kind of expensive mercury vapor lamp to get the appropriate wavelength at a relatively high power (UV tubes for PCBs, UVPROMs and night clubs are apparently NOT suitable). But nowadays this is sometimes replaced with much cheaper and reliable UV LEDs.
To increase resolution, it is tempting to print an enlarged mask of the chip and then use an optical system to scale it down to chip size. However, the problem here is aligning the different layers. Maybe a high quality optical photo scaling machine mounted backwards with a microscope plus micrometers could work. The idea is to align the chip under visible light and control with the microscope, then switch on the UV light for photoresist exposure. The problem we might have is that the lenses can behave significantly differently at the two wavelengths, but maybe this could be compensated for.

Draft slides for the theoretical part are available at http://lekernel.net/presentations/FPGA_Workshops/091108_tmplab/scenes_draft.pdf.

Let me know if you have any comments. There will be of course more explanations than what is just outlined in the slides.

It’s still time to register on the /tmp/lab wiki page.

The workshop is free of charge and open to everyone with some interest in computing or maths. The venue is the /tmp/lab, a hackerspace located in the Paris region.

See you on Sunday!

DESCRIPTION
In the previous workshops, we have seen that FPGAs can emulate any logic circuit without moving (mechanical) parts.

FPGAs are however not magic nor mystical devices and this workshop will shed light on how they work internally. After theoretical explanations on their functioning, we will program them very close to the “bare silicon” by configuring manually each logic element on the chip, without any Verilog or schematics.

This will give you a better understanding of the challenges involved with writing open source programming tools, reverse engineering existing FPGA designs, injecting backdoors into FPGA bitstreams, and squeezing the most performance out of an FPGA chip.

PREREQUISITES
For the hands-on part:

• Bring your laptop
• IMPORTANT: Install Xilinx ISE. The installation takes a long time that we cannot waste during the workshop.
• Bring a Xilinx FPGA board such as the Avnet Spartan-3A starter kit used in previous workshops.
• The board must have a Xilinx FPGA. Boards with non-Xilinx chips cannot be used.
• Your board must have at least 2 pushbuttons and 2 LEDs.
• Bring any required programming (JTAG) cable and try to make sure that it works (driver installed etc.) before coming.

You can come to the workshop without a board, but obviously you might be unable to perform the manipulations yourself.

PRACTICAL INFO

• Venue: /tmp/lab near Paris, France
• Date: Sunday November 8th 2009, 14:00-19:00+
• Language: FR/EN (depending on attendees)
• Price: Free of charge, however donations to the /tmp/lab non-profit organization are welcome
• Please subscribe by editing the wiki page: http://www.tmplab.org/wiki/index.php/FPGA_Workshop_4:_Behind_the_Scenes