Stand alone Uno

Hi, I have built my project using an Arduino Uno board (New version), and now that it's working as expected, I would like to develop it as a stand alone, using veroboard for the PCB. I have seen http://arduino.cc/en/Tutorial/ArduinoToBreadboard and http://arduino.cc/en/Main/Standalone. Is the circuit connections the same for a Atmega 328P-PU as in http://arduino.cc/en/Main/Standalone or is there a better circuit diagram of external components/connections available anywhere? I will be pre-programming the chip on my Arduino board, and then fitting it into the new board, so I don't need a USB/serial connection.

Also, any problem with fitting a 1A 5v power supply (so it can power some relays too).

Try this one: Add 7805 with 1uF polarized caps on input & outout. AGnd & Gnd, pins 8 & 22, should connect to the 7805 Gnd also, got left off the drawing.

Add a reset switch if needed.

CrossRoads: Try this one: Add 7805 with 1uF polarized caps on input & outout. AGnd & Gnd, pins 8 & 22, should connect to the 7805 Gnd also, got left off the drawing.

Add a reset switch if needed.

Thanks, that's much clearer. Any idea what purpose caps C1 & C2 serve, as they are both connected across +ve & grnd?

Pin 22/lower cap junction and pin 8/lower cap junction both need a downward pointing arrow to signify a ground connection to those points.

Lefty

Thanks, that's much clearer. Any idea what purpose caps C1 & C2 serve, as they are both connected across +ve & grnd?

They are called bypass or decoupling capacitors and are a part of any well designed digital circuit. Although schematically they are across the power supply lines physically they are right next to the IC pins and serve to filter out noise, spikes, and other bad stuff. The circuits that do not have these capacitors, like the ones in your links, are just not well designed. Remember, anyone can post a circuit, they do not have to be competent to do so. (Crossroads [u]is[/u] competent.)

Don

floresta:

Thanks, that's much clearer. Any idea what purpose caps C1 & C2 serve, as they are both connected across +ve & grnd?

They are called bypass or decoupling capacitors and are a part of any well designed digital circuit. Although schematically they are across the power supply lines physically they are right next to the IC pins and serve to filter out noise, spikes, and other bad stuff. The circuits that do not have these capacitors, like the ones in your links, are just not well designed. Remember, anyone can post a circuit, they do not have to be competent to do so. (Crossroads [u]is[/u] competent.)

Don

Thanks Don, makes good sense now you've pointed it out.

I updated the picture to show the grounds that I had noted in the text were missing. Should show up with a refresh ...

Hmm, or not! Hopefully this one will show them ....

Here's one in a design.

I am getting a lot of use out of the pololu.com terminated wires & crimp connetor housings!

CrossRoads: Here's one in a design.

I am getting a lot of use out of the pololu.com terminated wires & crimp connetor housings!

Neat job, mine looks like a bowl of spaghetti!!

Well, we did build 12 of of them, so we had a little practice 8) The crimp connecter headers & connectors make it pretty easy to keep neat.