implementing moving averages

Hi,

I've got interested in currency trading recently so reading, learning etc. I plan to build a system to test some ideas but need to implement indicators first (yes, I'm building my system from scratch inspired by some members of this forum).

I started with implementing moving averages (SMA, EMA). While the algorithm itself is quite easy, it applies fine to daily recalculation while I think something more up to date is required to make a decision even if these indicators are quite reactive. Could you please advise me what is a reasonable interval to recalculate these indicators? Every tick, minute, 10-minute, hour, day?

thank you

G.

Tick seems to work just fine.

if I recalculate SMA for every tick then there is a problem with period definition because as I understand, an instrument can tick at any interval, therefore to calculate 1-day SMA I need to make an assumption that tick happens every second for example, and then it's not 1D SMA but simple moving average of the last 86400 ticks. is it correct? (I'm looking into algorithms which adjust SMA with every update instead of recalculating it http://en.wikipedia.org/wiki/Moving_average)

regards