Need help with powersupply

Im working on a controller for a road barrier and need some help.
Im controlling it with a atmega328 chip, and a ebay radioreciever/transmitter.
Need some help with my powersupply. Looking at the picture, is this ok?
Sorry for bad drawing..

Basic but it will work. I would suggest a big smoothing/reservoir capacitor on the output of the bridge to help with the ripple and maybe a current limit resistor.

Im totally new to this. How big aprox will you think?

And how do I set a current limit resistor?

any reason your not using an off the shelf supply ?

well, this goes into an application on a pcb im etching myself...

so an off the shelf dip dcdc would fit well ?

well, I guess it would.
But I already have plenty of 7805, so then I dont need to order new parts..

Ok,

so yes all is good.

I'd probably put a 100 nf capacitor on the outputs in parallel with the output capacitors,

what sort of current you looking at ?
the 24 volts ac is going to rectify to something like 19 volts dc, ( its something like that )

so your dropping 15 volts to the 5 volt output,
if thats at 250 mA, your dissipating 3 plus watts in the regulator.

hence question about dcdc.
you could also look at an ac:dc switcher,