Featured Engineer

Interview with Mathieu Stephan

Mathieu Stephan (limpkin)

Mathieu Stephan - Embedded systems engineer and open source hardware enthusiast

Can you give us a little background about yourself? How did you get into electronics?

Unlike most electronics guys out there, I didn’t get into the field until I was 18 years old.
I actually remember tinkering with my dad’s small electronics kit (similar to this one:http://transitek.com/photos_produits/6/6_EL1301.jpg) when I was 14 but I couldn’t understand a thing I was doing. I also played a lot with Legos.

After getting my baccalauréat at 18,because I was always in front of my computer (instead of being outside) I decided to get into an electronics & informatics engineering school. A few months later, a friend I made at school gave me several components (an Atmel microcontroller, a photo resistor, diodes, resistors, etc.) and it was only then that I realized the potential of electronics, realized that I could do anything I wanted with them.

Tell us about your blog limpkin.fr?

As I started to make many projects for my pleasure, I thought that leaving a finished project on a shelf was just a waste. I decided to make a blog to share them, but especially emphasize the thoughts that lead to the choices of components / architecture. I also didn’t see the point in keeping the source files for myself, so for every project description comes all the resources needed to modify/replicate it. I guess it was some early open hardware initiative! I chose to write my blog in English to get better at it.

I honestly think it is the perfect way to get feedback and critics on a project. People around me don’t necessarily have a lot of knowledge about the field, or they simply don’t have the time to understand/check the inner workings. As I am a bit of a perfectionist, I like to know if I have really thought of all the possible ways to achieve a particular goal.

Starting a blog is a good tactic for geting to know people from around the world, and making new projects with them. Many people contact me so I can give them additional details on topics related to the ones on my blog, which can lead to new collaborations. I really want to motivate people to tinker with electronics circuits, and I believe that ‘inspire by example’ is a good method.

Can you tell us about designing your Whistling project and the response you have gotten about it?

I’m always looking for ways to simplify basic actions, in this case flipping a switch to turn on the light.
I had had this idea for quite a while, but before trying it I was waiting for a good microcontroller to get released so I could implement a solid whistle detection algorithm and build a cheap product.

The response I got was quite amazing. People seem to love this kind of 21st century gadget, and I am astonished by what they can do with it. Some guy in Colorado used it to control a robot! There are still some people, however, who have trouble understanding that this technology is way different from those disastrous “whistle to find your keys” gadgets from the 90s.

What other projects are you working on?

A company near where I live in Switzerland would like to commercialize my toktoktok project (knock detecting device) so I’m completely redesigning it to be more attractive and easy to use. I’m not very good at design and plastic injection, so it’s a good way to learn.

I’m also working at home on a work-related project, which is a rack-based platform originally aimed at facilitating the realization of quantum physics experiments. To put things simply, it is a rack in which you plug 3U ‘modules’ that perform particular functions (such as signal generation, combinatory logics, or measurements). The platform is then controlled by a computer or tablet PC, as the rack is connected to your local network. With the platform there is no need for a complicated electronics bench anymore, you can just use the rack and modules that suit your needs. The complete project will be open hardware and software, so I hope people will modify it to perform many different things.

Finally, I’m also working on a high-tech wooden totem for my father’s carpentry (details will be released on my blog in a few weeks).

What tools (software and hardware) are your favorites?

I’m actually migrating to Kicad for most of my new projects (schematics + layout). This software has gone a long way since its birth and I look forward to more functionalities coming from its creators. For more advanced projects, I use Allegro from Cadence.

On the hardware side, I’d have to say my favorite tool is my infrared preheating plate that facilitates a lot my soldering work. Besides this my favorites are regular tools, such as my soldering iron, oscilloscope, logic analyzer, microscope, etc.

What was the trickiest bug you ever fixed?

I usually try to avoid using libraries, but for one project I needed to use the gnumonks at91lib to implement a composite communication and storage device on an Atmel ATSAM3U. When using both functionalities, the data transferred was corrupted. I spent three days browsing through the lib to understand all the function calls to see what the mistake was. Turns out the microcontroller’s USB endpoints needed to be initialized in the “1,2,3,4….” order. Obviously, you don’t have any idea how these are initialized when using a library.

What is on your bookshelf?

Many different books, not only about electronics, but also novels, cartoons, cooking, and history. When I need to learn something, I usually get the information/ebook on the internet as I’m too impatient to wait for my order to arrive.

So I use my bookshelves to store all my development boards, past projects that I try to reuse, components stock and my (many) impulsive buys from ebay.

Do you have any experiential stories you’d like to share?

I don’t have one in particular, but I’m a true believer of the “what can go wrong will go wrong” saying.

Once, I actually managed to cut the electricity off at my work because of a faulty power supply.

What do you do when you’re not working on Limpkin.fr?

It’s hard to say, given that when I have some spare time I immediately start working on new projects. But I try to take some time off for skiing or climbing, depending on the season.

Is there anything you’d like to say to young people to encourage them to pursue electronics?

I may be pessimistic, but I don’t think that anything someone says can encourage young people. I do believe you need to show people example of what you can do to get them motivated. So have a look at my blog!

A word about the electronics community in France and 0Switzerland:

I envy all the small groups getting together in the US to make the wonderful projects we can see on kickstarter these days. I personally have the feeling that it is a bit harder here to get the “let’s get together and make a nice project” innovative spirit when financial returns are a remote possibility. So if you’re looking for partners to make something just for the sake of it, please drop me a message!

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