Wednesday, March 4, 2009

Well, the first parts arrived the other day, so I can finally start playing - How exciting :-P

First up, I got my first Arduino Duemilanove board (I actually got 2 boards, one to play with and one for the actual project!). It really is a very impressive piece of kit and incredibly easy to set up.

Within minutes I'd got the IDE downloaded and installed (that is to say, the USB drivers installed, the IDE is a standalone app that requires no installation!) and was running my first program to make the on-board LED blink! WOW! ;-)

Yeah, a very basic program but it does test that the board is working OK and is also a good demostration of how quickly you can get to work!

The next 'big' part of the project was the dispay device. This is a 4x20 character LCD display with I2C controller from Comfile Technology (CLCD420-B).

The display itself is actually a Palm Tech PMC2004E-SBLW display. The controller seems to be a custom built controller which actually uses an Atmel ATMega48 micro-controller (The 4KB version of the micro-controller on the Arduino board!).

I had originally intended to do some more example programs with the Arduino, but curiosity got the better of me, so immediately after the LED test program, I decided to hook up the display to the Arduino's I2C bus and set about that old favourite "Hello World" program. :-P

Again, simplicity in itself! Simply connect up the two I2C lines and the +5v and GND connections. Link in the Wire libraray provided by the Arduino IDE, then simply call the various wire functions to start sending strings. All in, probably only about 20 minutes to work everything out and get Hello World going!


  1. Looks good.

    Do you have any information about how to trigger the 450? type of signal etc (TTL)?

  2. Hi Sjoerd, the 450D uses a 2.5mm stereo type jack for the remote trigger, so there are three connections, the tip, the centre and the shield. The tip of the jack triggers the shutter, the centre triggers focus and the shield is a common ground.

    Power is provided from the camera and you just need to close the circuit between either the centre or tip and ground to focus and shoot respectively.

    Normally the remote trigger just uses simple switches to close the circuit and trigger the camera, nothing more is required. However, to trigger electronically without risking to damage the camera, you need some sort of isolated switch.

    A relay would be the simplest solution, however they can be quite slow particularly when the point of your trigger is for high speed photography. The better solution is to use an opto-coupler.

    I will post a circuit in the next day or two. Meanwhile, you can see the basic idea here: