Carlitos’ Contraptions

I think I can now safely say I am a Maker. I make things and that is what I like to do. Let me explain why I came to this conclusion.

Around five years ago when I was in CEGEP (an obscure educational stage in Quebec between high school and university), I went on a humanitarian trip to Ecuador with my fellow students, in which we mainly planted medicinal plants, trees, taught English and built two bunk beds from scratch. It lasted roughly two weeks and left me with the desire to go back and do more

Now, five years later, I went back. The only difference is that now I am an Engineer (Jr. I might add) and was responsible for two overly awesome projects: the construction of a wind turbine, and of a solar water heater.

I travelled with this year’s International Baccalaureate group. Needless to say, being back with an IB group brought me very good memories of my previous trip and all things IB (such as Cardiff).

As expected, the construction of both projects did not go without troubles. There where many unexpected obstacles and a lot of hard work was required in order to complete them. Luckily, I was with the best group of young people I have ever encountered. The Andre Laurendeau IB group of 2010 that travelled with me is remarkable and exceptional. Composed of Nicolas, Roxane, Tiberiu, Angelo, Geneviève and Adam, this is a hard-working, tenacious and dutiful team.

IB 2010 group in Quito, Ecuador

As you imagine, I loved this experience. So much so to be already toying with ideas on what to do next year  for the next trip. Although I might not be able to go, I might still be able to imagine some cool projects.

Acknowledgements

I would like to thank the IB in entirety for all the hard work they put in this project, not only thinking about the design and building it, but also for all the fund raising activities that made it possible.

Also, I would like to thank Stephanie who donated many of the awesome tools I brought to Ecuador and that were crucial in making the projects. The single most important tool she gave me being the Leatherman Wave (for Christmas) which is responsible for achieving almost everything during the trip.

Leatherman Wave in Action

Forced Acknowledgement

The OQAJ founded part of this project and deserves my gratitude. If I say it is a forces acknowledgement, it is precisely because I am forced to publicly thank them. I am very grateful for their support, but I do not enjoy being coerced into doing anything. It would have been much more appropriate if they would have just kindly asked for a public acknowledgement. Or, even better, if they were confident enough that they are being helpful so to think people will thank them naturally.

What about the Projects?

I know, I started with all this Maker thing and so far there are no instructions, no pictures of things being built, etc.

The projects deserve a lot of writing, so I will dedicate one, if not several, posts to each one of them: the wind turbine, and the solar water heater.

Stay put for more!

Ever since the implementation of the new Opus Card system by the Montreal’s Public Transportation (STM), there have been lots of malfunctions and bugs.

Crashed STM Ticket Vending Machine

The malfunctions were mainly caused by the poor build quality of the smartcards, the poor wireless reader range, the easy demagnetization of the paper tickets, etc.  Slowly (very slowly) these malfunctions are being addressed and (sometimes) solved. The unsolved bugs become a part of the daily routine and we Montrealers learn to accept them.

On last weekend, I witnessed a bug that I would have never thought possible in a professional widespread software application that involves so many money transactions: what I usually call a boundary condition bug.

The Bug

Quick note on the STM’s fares (for those who do not live it day-to-day):
There are mainly two transportation systems: the bus and the metro (subway) and the fare pricing is governed by a (somewhat) simple set of rules:

• There are monthly passes that allow unlimited fares within the month in both the metro and the bus. They are more expensive for adults than for students or elders.
• There are weekly cards that are similar to the monthly cards by work for a given week.
• There are tickets (either as a magnetic paper card or as some information on a smartcard) which allow for one fare that allow to take the metro, the bus, or both within a two-hour time limit. Should the time period be elapsed, or should you take the metro or the same bus more than once, you will need another ticket.

Since the Opus Card implementation, one of the first things that came into my mind was the attention required to compute the fare price when a month ends (i.e. at 12:00 on the 31th, 30th, 29th, or 28th), or when a week or a day ends. Everyone who has programed at least a little bit (like me) knows that these boundary conditions are usually exceptions to the normal behaviour of a program and need to be taken into account. I, of course, assumed that such mundane exceptions would be addressed by professional programmers swiftly and painlessly. I was wrong.

On last Saturday, my girlfriend and I took the metro after going to the movies and she swept her card (loaded with tickets) at exactly midnight (00:00 as reported by the STM records) at the metro reader. Around 20 minutes later, we walked into a bus and surprise! another ticket was charged instead of using a transfer from the previous ticket.

The conclusion to this is that when a day ends, there STM fare algorithm fails and defaults to charge you an extra ticket. Unfortunately, It is unlikely that this bug is noticed by the STM any time soon since they are not loosing any profit from it and they do not accept bug reports. Even the lady at the reclamations booth had a hard time to understand what the problem was.

In the end, instead of a full refund she got a “courtoisie” ticket which expires on next Sunday (instead of a regular ticket that which expires in around two years). So much for costumer service.

The poor programming quality is also reflected by the poor choice of OS for their vending machines. Let’s just say that using Windows Embedded is the equivalent to eating a faulty grenade: it will rather sooner than later get ugly.

Workshop wall

This is a very simple and quick hack that anybody can do. The objective is to build a holder that will keep all the precision screwdrivers in one place and facilitate the access to them (i.e. it should be easy to see which one is which and they should be easy to take).

Materials

• A plastic container cap (I love caps)
• That’s it, you do not need anything else

Tools

• Drill or strong scissors
• Precision screwdrivers
• A nail (maybe)

Doing it

Screwdriver Holder

1. Drill or cut a big hole on the top of the cap. This hole will be used to suspend the screwdriver holder.
2. Punch in the Screwdrivers in  the rim of the cap. If you do not trust your screwdrivers to pierce your cap, you may use a nail. Keep in mind that the screwdrivers have to be very snug in the holes since they are only being held-in by friction.
3. Celebrate! you are done.

I just got a shiny new Logic, a tiny 8-channel, 24 MHz logic analyzer from Saleae LLC, and it is beautiful. I’ve been wanting to get a logic analyzer for quite some time and this little guy is definitely worth the 150 bucks it costs.

Logic Unboxing

Logic Analyzer?

(skip this if you already know what a logic analyzer is and do not want to be bored to death)

A logic analyzer is a measurement instrument that allows you to record the logic level (e.g. high or low) of a digital signal throughout time. This means that if you are working with a micro-controller and want to know what is actually happening at the pins, you can use a logic analyzer to record the signals of interest and display them on a time-line on a computer screen. This is very convenient considering that debugging microcontrollers often implies guessing or using lame techniques such as slowing down the execution time and lighting up LEDs in order to see what the program is doing.

In short, a logic analyzer allows you to view digital signals and plot them with respect to time.

Casing

The Logic, by Saleae

The Logic has a nice square anodized aluminum body which makes it very sturdy and looks awesome. It is very small (~ 4.5 cm on the side and ~ 0.7 cm high) and features some male headers on the front side and a mini USB port type B on the back. For some reason, I really like the four tiny hex screws that hold together the two aluminum plates that make the body.

Accessories

Cabels & Hooks

The Logic comes in a nice Logic Case, usually intended for some other electronics such as external hard drives I suppose, that can accommodate itself  and its USB cable, its set of wires and the E-Z-hook clips.

What I enjoy the most is that the wires are robust and kink-proof, and they are terminated in female headers, which makes them very easy to use in breadboards and on male pins in general. Also, the hooks are removable and they can connect to harder-to-access pins in a secure way. The wire colour coding follows the resistor colour coding (i.e. Channel 0 is black, channel 1 is brown, etc) and this might be a bit confusing at the beginning since the Ground wire is grey instead of being the usual black.

Finally, the carrying case is a very nice feature since it allows you to have the Logic and all the related items in one single place. The case is a bit too big, but I the extra space could be used to store some extra accessories, such as headers gender-changers (for plugging into female headers) or wire extensions with special ports (e.g. DB-9, RJ-45). I also enjoy the fact that all the components come in their own little zipper-bag that allows you to store the unit in a nice pristine condition (it may not seem like it, but I like to preserve things in their original state, unless they come from the garbage in which case I mod them and unscrupulously use their pieces).

Hardware

I did not want to take the Logic apart in order to see its guts (so far) so I do not have too many details about the hardware other than what is listed in Saleae’s website: (1)the inputs are protected to you don’t fry anything, (2) it can sample at 24 MHz,  and (3) it is able to store up to 500 M samples.

Software

The software can be downloaded for free (and used in demo mode) looks really nice but unfortunately, the current stable version works only under the Redmond OS and it does not play very well with Wine in Linux or in my XP virtual machine. I would have really liked to test its Protocol Analyzers, a function that automatically sets the names of the signals and decodes the information accordingly to the protocol being analyzed (e.g. I2C, RS232, SPI, 1-Wire).

Anyways, there is an upcoming cross-platform version of the software that looks very promising and is currently under private beta at the moment. Of course, I could not resist the urge to join the beta testing and I can say that the new software is working very nicely (so far, I have not tested it extensively yet) under my 64-bit Kubuntu setup.

Needless to say, as soon as the software goes public, I will post a more thorough review, so keep posted.

Conclusion

The Logic is a very nice piece of equipment for any hobbyist or professional (provided you do not require to read signals faster than 24 MHz, which is rare specially while debugging). It is built to last fits very nicely in a hacker’s toolbox (or even pocket). I would recommend the Logic to anyone needing a sturdy and easy-to-use Logic analyzer, and I will be using it in my upcoming projects.

Google Wave

I finally got a Google Wave account and I decided to do something for the community. More precisely, the hacker/tinkerer/DIY community.

I think it would be rather interesting to have a place where to share, showcase and discuss projects and hacks with local people (from Montreal).

If you want to join the wave you can find it here.

I hope this will result in a stronger more connected Montreal Hacker community.

Cheers, and see you on the wave!

I have a few Wave invites left so if any geeky Montrealer would like one, please leave a comment and I’ll see what I can do.