Using arduino with LDRs and Max/MSP

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello,
I am using an Arduino (Duemilanove) with an LDR, in the hope that I can have it trigger a sample in Max/MSP.
It's for a University project, and my knowledge of Arduino, electronics, and Max/MSP is very limited so apologies if you don't follow my ramblings.
I simply need my hardware set-up to be checked for wrong doings, and my software set-up to be checked even more as I have less of a clue with this.

I have a little circuit set up, using this blog as a guide:

So, using a breadboard I have wire from the 5v to one leg of the LDR.
Wire from the other leg of the LDR to analog pin 0.
Variable resistor on the breadboard in between the 2nd leg of LDR and the wire to analog pin 0.
and from another leg of the variable resistor to the ground on the breadboard.

All of this is direct from the linked blog above.
And if it makes a difference the LDr is 36kOhms - 88kOhms, and variable resistor is 100kOhms.

On the software side of things I'm attempting to use Arduino2Max as per:
http://www.arduino.cc/playground/Interfacing/MaxMSP

I have opened the given Arduino2max sketch in 'Arduino', and have copied both the 'pull down menu' part and the analog pin reader of the max patch provided and put them into my own patch.

I am using the free trial of Max/MSP as I have no plans to 'bounce' any patches at least for now.

Should this set-up work as it is?
Do I need to activate the sketch in arduino somehow or does having it open automatically have it detect readings and send them to Max/MSP?

As it stands I have no readings coming in, but then as stupid as it sounds I am just expecting it to work as I've done what the guides I've read have said to do.
Thanks,
Alan Joesbury

...apologies for the essay.

2

I have figured out my mistake, and it's a very silly one.
After a few days of being horribly ill I remembered that the arduino software had an 'upload to I/O board' and before it hadn't even occurred to me that this meant to programme the board with whatever programme I had..
Anyway I've done that and after testing out a few different LDRs (whilst varying the variable resister) I have a winner!

The next step is to build an extension on the patch I have already that will trigger a sample when a certain value is reached.
Does anybody know how I can do this?
For now I am looking through the strangely labelled objects and not having much luck.
Cheers,
Alan

3

I realise this is now a Max/MSP issue I need help with so I guess this thread can be closed.

Cheers anyway, and if anybody is doing a similar project and needs my help at all or any questions answered (now that I've conquered this bar one software issue) I can be found at http://alanjoesbury.blogspot.com/

Thanks,
Alan