The Sweet Spot
On software, engineering leadership, and anything shiny.

Ohm gotchas

Here’s a list of things that have been annoying, or at least a bit frustrating using Ohm, the Redis ORM, in a Rails app. Beware to those who assume Ohm is ActiveRecord in new clothes. It is, but it’s not:

CRUD

Don’t make the mistake of treating your Ohm objects like AR:

ActiveRecord Ohm
destroy | delete`  
self.find(id) self[id]
update_attributes update
create create

Also note that Ohm’s update_attributes behaves differently from Rails` – it doesn’t persist the updates to DB. That owned me for the good part of the day.

Callbacks

Thankfully, these are ActiveRecord-like with the addition of ohm/contrib.

Associations

ActiveRecord Ohm
has_a or belongs_to reference
has_many collection

Read this article if you’re considering creating associations from AR objects to Ohm objects and the other way ‘round.

Now at Blurb

I should have mentioned this long ago, but I started work at Blurb in early August. It’s been a quick ramp-up and I’m loving it there, surrounded by smart engineers and great designers. I do Rails/JS work there, and I’m building a lot of chops around Agile/TDD methodologies.

Anyways, they had me do a Camera Thursdays blog post, which I wrote about my Nikon/1.8 camera combo:

mmtss, a collaborative loop station

mmtss is a loop station built for live performances.

Let’s make music together! This project simplifies a traditional loop tracking station and is designed for interactive collaborative music performances.

The idea: Everybody adds or modifies one “part” of a 32-bar loop. The user gets to play an instrument over the existing mix and record the 32-bar phrase when she or he is ready. Once the person is finished, the project selects another instrument at random for the next viewer to record.

It’s an Ableton Live controller serving a Webkit view, backed by node.js on the backend and socket.io + RaphaelJS on the front. Communication is done through a LiveOSC Live plugin via sockets.

Displayed at the Regeneration “We Collaborate” art show in Oakland, CA. 9/24/2011.

Screenshots

Practice mode

mmtss in practice/playback mode. Here the user is able to practice/mess around with the current instrument to prepare to record the next track.

Cued mode

Pressing “record” puts the user in a wait state. They are prompted to begin recording when all the black boxes count down and disappear.

Record mode

mmtss in record mode.

More screenshots: http://www.flickr.com/photos/andrewhao/sets/72157627640840853/

Source code

Github: http://www.github.com/andrewhao/mmtss.

MIT/GPL-sourced for your coding pleasure.

Installation

  • Make sure you have npm installed: http://www.npmjs.org

  • Copy lib/LiveOSC into /Applications/Live x.y.z OS X/Live.app/Contents/App-Resources/MIDI\ Remote\ Scripts/ folder

  • Set it as your MIDI remote in the Ableton Live Preferences pane, in the “MIDI Remote” tab.

Running it

  • Open Mmtss_0.als as a sample Live project.

  • Install all project dependencies with npm install from the project root.

  • Start the Node server with node app.js from the root directory.

  • Open a Web browser and visit localhost:3000

Modifying the sample project

You can modify this project to suit your own needs. Note that there are two sets of tracks; instrument (MIDI input) tracks and loop tracks that actually store clips.

For n tracks, you can add or remove your own instruments. Just make sure that instrument at track x corresponds to track x + n.

Credits

License

MIT and GPLv3 licensed. Go for it.

You will, however, need to get a license for Ableton Live yourself.

The handsome collaborators

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Introducing Boink, a photobooth for the rest of us.

My friends were complaining that wedding photobooths were too expensive to rent. Could we make one for them?

Glen and I from the Porkbuns Initiative stepped up in full armor, ready to help.

What is it? It’s a self-running photobooth that uses your Mac for brains and DSLR for eyes and a Webkit browser for its clothes and a photo printer for… a printer. You can connect an iPad as the frontend for a nice visual touch (pun intended).

We built it on a backend Rails instance, pushing SVG+HTML5 in the frontend and using the gphoto4ruby gem as a camera library wrapper.

[caption id=”attachment_1105” align=”alignnone” width=”500” caption=”All dressed up and ready to go.”][/caption]

[caption id=”” align=”alignnone” width=”500” caption=”An early UI prototype.”]Boink Preview[/caption]

[caption id=”attachment_1106” align=”alignnone” width=”500” caption=”This comes out of the printer.”][/caption]

Try it out

Check it out on Github.

Chat App - Frontend Prototype

Chat View - 1

Interview View

Some UI work I did for a stealth startup in early ‘11. Responsible for look & feel and frontend chat interactions. jQuery/UI communicating to a CakePHP/nodejs backend.

We developed this prototype with statecharts, a concept commonly found in event-driven programming and with which I first learned from Sproutcore. I found it really helped map out all the complex user interactions we had to deal with on the page.

See more screenshots from the set.