writes code and visualizes data
in Montréal, Québec, Canada.
So I finally got around to working on my Silvia Mod Plan, getting all the way to Step 5! The video above is a demo of the setup I have to show a real-time graph on my iPad of the boiler temperature in the Silvia.
Having installed the thermocouple in the Silvia and played with my TC4 shield, my initial plan was to use the Arduino to transmit data to my iMac using XBee as a wireless serial link, where I would run a NodeJS process which would read data from the USB port and which would communicate with the iPad via a WebSocket over Wifi (phew, mouthful!). Ideally the Arduino would speak Wifi but in the meantime I figured I'd play with this setup. I chose NodeJS because it seemed really easy to set up WebSockets using socket.io, and that seemed like a good way to feed data to Smoothie Charts for real-time graphing. I rewrote the code in CoffeeScript, because it's the best way to write NodeJS code IMO (a discovery I made after writing the first version of this code 4 months ago) and because it's so fitting for this project!
So in October I finally bought the Rancilio Silvia I'd been coveting (after coveting a La Pavoni manual espresso machine first!) with the intention of modding it to add digital temperature control to it, as many have done. This basically involves replacing the stock thermostat with a thermocouple and solid-state relay, plugged into a digital control unit which does PID control. Now being a software guy who likes to tinker with his Arduino, I pretty quickly decided that I wouldn't use a standard industrial controller but I would build a custom one (kind of like this one, but read on for differences). In addition, I decided I didn't want to hang anything from the Silvia or make any externally-visible modifications, partly for esthetic reasons, but mostly because I'm not too good at making good-looking hardware myself. So I decided I would build something I could control wirelessly, from my iPhone for example. "Control" in this case basically means occasionally changing the set point of the controller, and maybe turning it on remotely. One other feature which would be nice would be a timed on/off feature, like "on 30min before I wake up" and "off after 1h of disuse" or something like that.
On Saturday I attended hackMTL, a one-day hackfest/competition. The ground rules called for creating an app using at least one of a list of API's. The one that caught my eye was the DokDok API (now Context.io), which basically gives you programatic read access to your GMail inbox via HTTP/JSON. Since June or so I've been doing more and more visualization of data that I work with (first at Bell then at Recoset) so I figured I'd see if I could make an app that could make a neat picture of my social network, as it's represented in my inbox. I didn't quite finish an "app" per se during hackMTL but I did manage to make a pretty picture (above). The code is up on GitHub, and basically it's a Python script that creates a JSON file which is rendered using Protovis. The circles/graph nodes represent email addresses (aka people) and the links between nodes indicate that the two parties were on the same GMail thread.
After building my little autonomous wanderer robot, I saw this iPad-controlled blimp and went ahead and added iPad control to my robot too. I had a Python script on my iMac which took commands from the iPad over Wifi and relayed them to the Arduino using XBee. I demo'ed this at BitNorth 2010, but I'm not sure if the video is up yet. That said, the fact that all the commands were relayed through a 'base station' bothered me, and I saw a cheap wireless Wii Nunchuk which I immediately bought, thinking I could make it into a really ergonomic remote control for my little robot. I probably could have gotten a Wifi shield instead, but I was up for a different kind of challenge.
Back in April I got an Arduino Duemilanove and a variety of sensors and actuators, which promptly caused me to go order a rover base from RobotShop.ca, and a few days later, I had put this little guy together! Truly, Arduino is an easy-to-use platform for this sort of thing. I went on to put together an iPad-controlled version as well as a wireless Wii-Chuck-controlled version but I'll post about those later.
From October 2005 to May 2010, myEWB.ca was Engineers Without Borders Canada's official online community system. During that time, tens of thousands of people used myEWB to participate in thousands of online conversations, send millions of emails, schedule hundreds of events, share files, apply to serve overseas, register for conferences, pay their membership dues and otherwise collaboratively work towards eradicating poverty. As the team leader and major contributor to the myEWB project, I am proud to be able to host a small page for OpenMyEWB: the now-open-sourced software that powered myEWB.ca.
I always have trouble remembering what famous people were alive when, and more importantly, who was alive during, before or after who’s life. It’s easy enough to remember which philosopher came before which other philosopher or which scientist came after which scientist, but often harder to remember which scientist came before which philosopher etc. So I built a PHP script to automatically lay out an HTML timeline to help keep all this stuff in context. I then decided to learn how to use XSL and rebuilt my little experiment using that. Click here with a modern browser to open the timeline.
You're part of a small-to-medium group of people who trust each other and have some reason to spend time and money together (e.g. you have a few housemates or you work in a friendly office environment). It's a huge hassle to constantly be requesting separate bills or lending each other money and losing track of who owes who how much and for what. You waste time quibbling over small amounts and people in your group don't like lending each other money or picking up the tab for lunch.
Using this simple web application, a group of people who trust each other can keep a running tab of how much they owe each other. This is handy for figuring out such things as who should pay for groceries next time (e.g. whoever owes the most) and generally makes people more easy-going about spotting each other money or picking up lunch, as they know they can keep track of it. With PHPTab, any member of your group can be as lenient or penny-counting as they want, without ever having to actually be constantly be trading small sums of money. It's just a matter of "putting it on their tab".