Cheap shield compat board for finished projects?

Once I've completed a project, I'd like to leave the Arduino in it (so it still works :-)). I would imagine that this gets expensive. Are there any rock bottom price bare-bones shield compatible clones that don't have stuff like LEDs, USB and maybe even the ability to program the Arduino (I'd imagine you'd pop out the AVR, and put it in this board). I think I'll I'd really need is power, the CPU, the oscillator, and the headers!

Yep well the problem is that the needs of every project would be different. By the time you include the (as you said) "power, the CPU, the oscillator, and the headers" all that's left to get rid of is the serial port... and a lot of people use that!

One technique, which is what I have done in the past, is to home-etch one of the single-sided designs that are out there. There have been a couple of excellent versions posted on the forums, one by westfw and one by Adilson Akashi - a google search will pull them up.

You could modify these files to take out what you want, or alternatively, just etch the board as is, but only solder in the parts you need. For example, you could leave out the serial port parts.

The final alternative is to buy a commercial "bare bones" board that has the same form factor as the arduino such that the headers are in the same place. Sparfun's: http://www.sparkfun.com/commerce/product_info.php?products_id=8943

As you say it just has the power supply, processor and the headers. It has a row of pins that match up with some of the USB->serial converters you may have seen. It's still US$20, so there is some savings, but not massive.

Thanks for the plug. I actually drew up (but haven't tested) "runtime" versions of my single sided board without comm or ICSP (removing ICSP makes the board much easier to make!) Unfortunately, my design is getting a bit "old" (being based on the original Arduino Serial board, which was pre-NG even.) http://picasaweb.google.com/westfw/MiscElectronics#5314019806612134274 There are some vendors who offer bare boards of shield-compatible Ardunios (or clones.) NKC has three different versions, starting at $2.99 (for a old-style Arduino-usb PCB, which should be fine for this sort of app with no USB components installed. And you'd be hard pressed to match that price/cost even with surplus PCB supplies and a school's PCB shop...) (now, my impression is that these are leftovers, and when they're gone, they're gone (except for the serial version?) But meanwhile, it's a good deal.)

I've liked the Duinostamp from Fundamental Logic, it doesn't get much more basic then that and you can purchase just the PCB if you have the other parts.

http://store.fundamentallogic.com/ecom/index.php?main_page=index&cPath=15&zenid=5e15a2dc55c76e43459318c877bf089a

Lefty

But the original poster was specifically looking for a "barebones" board that was still compatible with shields...

Excuse me, sorry

Thanks for all the replies! I'm sure that these links will help out a lot of people. For me, it is important to go with a shield compatible board, so unfortunately I can't use the really small breadboard devices out there. And personally, I guess if I was going to go through the effort of fabbing a new board I'd also customize it with my own logic and therefore minimize/eliminate the need for shields. So for me, the 2.99 NKC board seems like the right choice, as long as it works without the USB logic populated. Additionally, I happen to have all the components I'd need to populate it except for the CPU -- and of course there are a lot of places to get those.

Additionally, I happen to have all the components I'd need to populate it except for the CPU -- and of course there are a lot of places to get those.

Sorry to interrupt, but I happen to sell the CPU's too, bootloaded! You can save some additional money ordering from 1 place...

Sorry, the ball was bouncing and I couldn't resist kicking it to score!

Well, you scored! I ordered 3 PCBs and 2 CPUs. And it works so I'm happy too! For anyone else doing this its a little unclear what is the mininum you need to populate unless you look at the schematics, so I'll just summarize here, using the names silkscreened on the board. Maybe NkC can check my work!

I bought this board http://www.nkcelectronics.com/arduino-usb-22-pcb--nkc-versi22.html

Q1: oscillator. I used a 14Mhz part I got out of a Jameco grab bag of oscillators. So serial won't work, but then we aren't populating it anyway. PWR_LED and R7 (1k ohm): Optional (I think) if you want an indicator that you have power. I used a jameco grab bag LED and a 1/4 watt resistor IC2: use a 5 volt power regulator. I used L7805CV D1: Diode. 1N4004 suggested, but I used 1N4007 since 07 just has a higher reverse voltage C6,C7: capacitors. I used 25V 100uF electrolytic caps PWR SEL1: Jumper in the center on the right side, just short the center and the EXT (bottom) pin Headers: I used some nice wire-wrap from adafruit, but I think NKC sells these as well! CPU: I used the mega168

DC1: DC adapter socket if you want power. Actually, this is the one problem. The socket gets in the way of bending the power regulator down. And it needs to be bent down so shields can be plugged in. I ended up getting the DC-IN power from my shield board (down thru the header pins), but I would imagine that you could solve this problem by populating the part on the bottom side or by some very creative lead bending.

Then I carefully pried the CPU off of my Arduino using 2 jewellers screwdrivers in each end and stuck it into the board and it works great!