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[on:]

Heya!

I have a question, I've got my arduino up and running using sensors and actuators and i've got the function I want. Thing is, I'm designing it for a very small object. Is there any way for me to know what size a finished pcb might be that can offer the same function? I'm designing a casing and it's tough to know what sort of size i'm looking at. I've been dissecting watches and other small things so i know that some electronics are really tiny... I'm just really not sure about what my next step would be from arduino to mass production.

If anyone has any idea that'd be really useful!

-Susan

[Reply #1 on:]

If you can convert your design to a surface mount, the 328 chip can be reduced to a (TQFP_32_ which is smaller than a dime.  Mostly whats going to determine the size is things like power and any peripheral component.  Do you need usb support?  Modern devices has an arduino compatible product called the RBBB that is roughly 2 times in each direction the size of the 328p dip chip.

[Reply #2 on:]

Ah! brilliant, ok, I'll go with about 7mm square by maybe 3 mm deep? I just need to roughly model something for a concept on solidworks.

(I actually had to look up the size of a dime!)

I couldn't find anything with a search for (TQFP_32_ though

-Susan

[Reply #3 on:]

You can get a rough idea by adding up the dimensions of the package sizes.
At the end of the ATmega datasheet you will seen the various package sizes.
To reduce the PCB size you can go to a four layer PCB. This gives you more
more board area to run traces.

At ATmega328 in a VQFN is 4mm x 4mm. A QFP is 9mm x 9mm. The VQFN will
be expensive to prototype with since the package does not have leads. You can solder
and rework a QFP much easier than a VQFN.

The trade-offs are cost, size and ease of manufacturer and rework.

(* jcl *)

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[Reply #4 on:]

You can start from an existing board as a basis to your evaluation. For example if you plan to use a SMD processor you can look at the Arduino mini. From there you add your own peripherals around it.