Door bell timer using 555 IC?

[Mark Hennessy]

I'd also suggest that the 1k base resistor is a bit low - trying to shove the best part of 12mA into the base is not the best plan. 10k would be kinder, while still giving plenty of margin to ensure the transistor saturates.

I like the BC337 - good for 800mA while having a decently high Hfe. Here, the ubiquitous BC108 or BC458 will do equally well. Just about any NPN small-signal transistor will fit the bill. What Elektor magazine used to call TUN - see http://www.sentex.ca/~mec1995/circ/tuptun/tuptun.htm

I'm afraid that I've been really busy lately, but have been meaning to ask - any idea why the simple transistor circuits didn't work? Had I been less busy, I would have prototyped one for you...

I'll be at the NVCF as well. But no badge - you'll have to guess