How to Shrink My Project

I have just recently finished prototyping the main section of my project. It's a mod of an old RC toy which turns it to act as a photovore. I have the motors working and the RC functionality (excluding the remote) working properly.

Finishing up the prototyping with the photoresistors should be no problem. However where I get lost as a beginner is how to get my project into a more permanent and smaller state. I can't mount a full sized breadboard in the car and preferably I would ditch the Arduino altogether and just use a microprocessor (though I could use an Uno if it was advised).

I'm wondering if anyone has any tips, advice or links about how I could go about doing this. I need about 8 I/O digital ports and 2 more analog ports. I've done a bit of research to see what's available, but there are so many routes to take it's a bit overwhelming and I don't want to make bad decisions.

Any help would be greatly appreciated! Thanks.

Why not use one of the headerless Arduinos? Like a Promini? Not much more than a microcontroller there.

A Arduino Pro Mini is super small.
I bought a pro mini clone on Ebay for less than 5 euros.
But you need a seperate usb-to-ttl-serial converter to upload the sketch.

A Arduino Nano has a usb connector, so you don't need extra hardware.

There are more options. Like the Arduino micro, very small, and it connects to the usb.

My projects are usually embedded, no PC connection when running, so I regularly have USB/Serial off board for programming.
If end user is not intended to reprogram them, I'll go even farther and only put on an ICSP header and then skip the bootloader.

I need about 8 I/O digital ports and 2 more analog ports.

You could take a look at the Attiny84:

Thanks for all the great replies!

CrossRoads:
Why not use one of the headerless Arduinos? Like a Promini? Not much more than a microcontroller there.

Erdin:
A Arduino Pro Mini is super small.
I bought a pro mini clone on Ebay for less than 5 euros.
But you need a seperate usb-to-ttl-serial converter to upload the sketch.

A Arduino Nano has a usb connector, so you don't need extra hardware.

There are more options. Like the Arduino micro, very small, and it connects to the usb.

I've looked into this but there always seems to be a slight difference that scares me from my Uno. Any suggestion on what a good but small solution would be for a beginner?

CrossRoads:
My projects are usually embedded, no PC connection when running, so I regularly have USB/Serial off board for programming.
If end user is not intended to reprogram them, I'll go even farther and only put on an ICSP header and then skip the bootloader.

The end user is not intended to reprogram my project. What exactly is embeded?

Erni:

I need about 8 I/O digital ports and 2 more analog ports.

You could take a look at the Attiny84:

http://www.akafugu.jp/images/microcontroller-reference-sheet.png

I had considered this route and is what I originally planned on. Do you need a socket to solder a IC into perf board or can you solder the small legs on them?

Thanks again.

Make a stripboard Arduino clone, AKA the veroduino
http://nathan.chantrell.net/20110819/build-your-own-arduino-for-under-10/

There are lots of very compact and cheap Arduino clones which IMO are a far better bet than soldering up your own using stripboard etc. They're smaller, neater, probably more robust, and hardly any more expensive.

If you want any other devices (H-bridge drivers, keypads, displays, radios, batteries etc) then there are also clones which have these integrated onto the main board which makes the solution even cheaper and smaller.

If you're after small+cheap don't bother including a USB connection. There are small clones with them, but plenty of smaller and cheaper ones without, too. All you need is another Arduino running the 'Arduino as ISP' sketch, and some jumper wires between the two sets of ICSP connectors, and you can program your clone without it having a serial or USB port.

PeterH:
There are lots of very compact and cheap Arduino clones which IMO are a far better bet than soldering up your own using stripboard etc. They're smaller, neater, probably more robust, and hardly any more expensive.

If you want any other devices (H-bridge drivers, keypads, displays, radios, batteries etc) then there are also clones which have these integrated onto the main board which makes the solution even cheaper and smaller.

If you're after small+cheap don't bother including a USB connection. There are small clones with them, but plenty of smaller and cheaper ones without, too. All you need is another Arduino running the 'Arduino as ISP' sketch, and some jumper wires between the two sets of ICSP connectors, and you can program your clone without it having a serial or USB port.

What would be the advantage to buying a stripped down Arduino clone to soldering your own parts to board? I'm not against this idea at all, I'm just curious what I would gain.

Thanks for the continued responses.

A commercially produced SMD board will be physically much smaller, more robust and more reliable than an equivalent DIY through-hole soldered board. These things are extraordinarily cheap these days. There's hardly any saving to be had assembling your own, and you only need to make one mistake or need to buy in another reel of solder and it could easily end up being more expensive. IMO the DIY solution would have to be significantly cheaper to justify the extra work and poorer end product, and they simply aren't.