Events dear boy, events

I can imagine the look of surprise on your face. A new article has crept into your RSS reader, or perhaps by chance you decided to revisit my site and noticed a new post! Astounding as it may be, I do hope to get back into a more regular posting schedule now. The past few weeks have been hectic to say the least.

On a personal note, I’m starting a course in Computer Science at Royal Holloway, University of London in a week’s time. As a result I’ve been running around sorting out accomodation and so on rather than writing blogs. I’ve been spending the rest of my time working (the sort that pays), and the tiny little nooks and crannies of spare time are crammed with work on EVE Metrics 2.

In the past week I also received some donated server hardware; this will be taking residence in my new home and hopefully in the future the cluster will be spending most of it’s CPU cycles doing reports and more complicated econometrics using the EVE Metrics dataset- stuff that takes way too long to do online, but is achievable offline.

Anyway, back to business. Read on for the lowdown on EM2.1, new features, new uploader info and more!

Continue reading Events dear boy, events

Arduino Strobe Controller

So, we decided we wanted to use some strobes at the theatre this week. Unfortunately, we found them in a skip. They work fine, but there’s no remote control.

While the manufacturer (ANYtronics) does indeed provide their own controller, we wanted one in a hurry, so I put together a box which does the job quite nicely when all’s said and done.

At present it does:

  • Variable speed with preview
  • Keyswitch on/off
  • Momentary SPST trigger

It’s single-output for now. Considering the strobes have master/slave and can daisychain just fine, I didn’t see much point in doing this, at least for the initial version. The SPST momentary switch and keyswitch were both what I happened to have lying around in my box ‘o electronics stuff, and could easily be swapped for another solution. The SPST could be merged onto a switching rotary pot if you wanted to mimic the control on the back of the strobe precisely, but that wasn’t what I was aiming for- I wanted something that could be easily frobbed and adjusted in advance without having to guess at frequencies. That’s done via the three LEDs- green for power/system on (turns on with keyswitch), red for firing, and the third yellow LED pulsing exactly as the strobe would.

The whole job is fairly simple- it’s all active low TTL circuitry, using an Arduino Diecimila board as the brain. The Arduino manages the pulses, LED logic and switching logic.

The only complex bit of this came with the interfacing to the strobe.

The strobe’s interface is on a mono jack lead. After finding a socket, I needed to work out the pulse length and minimum interval. Given the specs list a 16FPS maximum, I settled on 64ms delay between pulses as a minimum. The pulse length I guessed at from the master-slave interface, again listed in the docs. Fortunately it seems the external trigger works on this too, so that ended up being the delay of choice therin. Code follows after the break.

Continue reading Arduino Strobe Controller