One option: go with 1A wallwart, cut the end off a USB cablle and connect to the board that way.http://www.dipmicro.com/store/DCA-05102nd option: use a 7.5V adapter into the barrel jack, the onboard regulator doesn't generate lots of heat creating just 300mA of current from a lower voltage source.http://www.dipmicro.com/store/DCA-07510
Well you didn't state what 'raw' DC voltage your starting with, but I would have issue that modern switching regulators are too expensive to use in small projects: I bought five of these recently and they should work well for small projects using just about any DC raw voltage I can dig up.http://www.ebay.com/itm/251066005460?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
bratan,If you want to use barrel jack as the connector for 5V on custom board, that's fine then. Low ohm PTCs only seem to be available in surface mount, 1206 size package.Zener is overkill if you use external wallwart, they have built in short circuit protection as well.
I assume if I just plug in 5VDC adapter it will work
Nope to OP. I've read your schematic, but i didn't find any decoupling on the chips... Place 100nF cap across supply rails on each chip. And make sure to place the Xtal close to the Atmega.// Per.
You want the decoupling caps right next to the power pin being decoupled.For the uC, that is right next to pins 10 & 30.What is HT1632? Is there a reason not to connect all Vcc & Gnd pins?For your buttons, it preferable to use the internal pullup resistors and use the buttons to connect the pins to Gnd when pressed.If you put a 1N4158 across R4, with cathode to Vcc, it will help prevent any odd latchup conditions when Reset is pressed.What happpens is Reset may cause a high voltage spike that the chip interprets as going into high voltage programming mode, and then appears to lock up.The diode dissipates that spike, and is found on current Arduinos.