Grand designs

I have set myself what I thought was a small challenge of building a timer to help with interval training on ergo's or ROWperfect's... it seems it might be a little more complex than I'd hoped... I was hoping not to bother my wife with questions about getting it working... (I'll keep them to a minimum I promise)... the timer will I hope chime at preset intervals over a workout period to remind you to change effort or rate intensity in training. Its on the drawing board, will blog its progress :o)