https://code.launchpad.net/~gentoo-members/bzr-gentoo-overlay/bzr-overlay-dev

As for more content and a non-trivial demo, I’m currently negotiating to run a hands-on, several hour class on Arduinos for the next Penguicon. There will be some sort of a lab fee, but as part of the fee, you’ll get an Arduino to take home, as well as all of the parts for doing the exercises from the class.

For what it’s worth, I think the first one was great for the target audience. It was just old news to me personally.

Fair enough on the second talk. The comment about contrasting was prompted by impressions from my post-talk talk with the “others” I mention. As for creating a better demo, if you don’t believe it can be done within your stated constraints, so be it; I am simply stating my uneducated desire to have seen more.

By the way, did you block me on Twitter? I hope we can still be friends. I didn’t mean to offend you with my subjective criticism.

Re: Open Hardware Overview

When the name of the talk includes the word ‘overview’, of course it’s going to be redundant for anyone who’s read up on the topic.

Re: Open Hardware with Arduino HOWTO

This talk was a HOWTO talk about the Arduino, not the Basic Stamp or other controllers. More to the point, it was a talk about doing Open Source development with Hardware. Most evaluation boards are ‘free as in beer’, but their development tools are typically expensive and closed. The Arduino platform actually is open at all levels above the microcontroller itself. I’m not saying its impossible to do open hardware development on other hardware, just that it is possible on the Arduino, and that the barriers to entry are very low indeed (the cost of an Arduino board).

I challenge you to give a soup-to-nuts software and hardware demonstration and do more than write ‘hello world’ in 45 minutes, complete with Q&A. While you’re at it, it all needs to be able to survive in checked baggage (because TSA would have confiscated it all from my carry-on).

If you need that resolution greater than 1 revolution maybe an optical encoder would be best? Or a homebrew optical encoder disk with the resolution necessary..

I should probably have pointed out that this is in no way a practical DIY project, otherwise I’d just use a GPS. ;)

Now you’re talking about introducing a CPU, memory, and a real-time clock. Calculate the rate of speed based on what input? If you want to use a simple optical tachometer, you’re talking about some tricky sampling. The extrapolation part sounds pretty flaky — it could get wildly out of whack if the user happens to stop without putting the correct foot down, for example.

You are absolutely right about the lateral displacement component. No idea how to compensate for that accurately. :(

Oh, I’m not actually talking about me. Let’s pretend it’s the mid-eighties at the height of rollerblade popularity, and GPS is still ten years away.

Also, you only have a transmitter in one skate, and a receiver in the other.

That being said, if I wanted to get this done and fast, I’d get a bicycle computer which use a magnet on the wheel and a little reed switch to detect when it passes. Some models allow you to input the circumference of the wheel down to like 1CM (so, way smaller than any bicycle application). Embed a magnet in a rollerblade wheel, etc. The problem with rollerblades as you pointed out is definitely that both aren’t on the ground always, that being said, spending a day skating around as usual will probably give you a fairly reliable correction percentage you can just add (by adding it to the wheel circumference in the computer). It won’t ever be dead-accurate, but it’ll cost ya $30 and you won’t have to program a damn thing.

Long time no talk by the way man…

Mike