Creating DIY Ardino's

Exactly. Plus, one pin (I think ADC3) can be used as a common for differential measurements.

Njay:
This is my DIY "arduino", although is little more than a breaduino on a PCB


EDuino

That is cool! - It reminds me a bit of our local hackerspace's own arduino variant, the LCD IO Backpack:

// Per.

Hey, good work on that LCD IO Backpack board! So you guys are making workshops around it?
I actually have also an (unpublished) design/prototype for an LCD backpack Arduino-platform based, the main difference being that it was designed to be standalone and provide efficient power to "expansion boards"; it's a bit bigger than the LCD to support a 1A switched buck converter, 3 buttons on the side, a power jack and a simple RS-232 converter - in a single sided PCB you can do at home (4 or 5 jumpers on the component side). I have some ambitious fw and PC sw plans for it, so it's still in the lab, right now being used as an I2C console to debug another project I'm working on!

Njay:
Hey, good work on that LCD IO Backpack board! So you guys are making workshops around it?

We did a single workshop around it. Usually if we make something small, we build one of these boards and use them. The small proto-area for SMD components is cool too.

We had a bunch of the PCB's fabricated, and when they are all used up, we'll make some changes on it, and maybe selling them outside Labitat - who knows.

// Per.

Good, that's good, go for it guys.
So that's an SMD prototyping area... good idea!

@Njay

I check your site, Nice work by the way. You say you can not use an auto-reset feature when your program the Arduino using the RS-232. Well you can ! It the DTR line... connect in serie a cap of 0.1 uF between DTR and the Reset of the Ardiuno. Program the ATMega328, and it will program just fine, and it will auto-reset. I did program an Arduino chip ( ATMega328 with Ardiuno Bootloader ) using a Schmartboard RS-232 Module at http://www.schmartboard.com/index.asp?page=products_populated&id=84 The RS-232 adapter is base on the chip MAX232.

For a cheaper Ardiuno... Buy a breadboard ( small is fine, a big one is better ) , a pre-loaded ATMega328 with Arduino bootloader, a 16 MHz crystal, one 10 K resistor, one push-on switch, a few 0.1 uF, 2 - 22nF, somes wires - The comunication module : A FTDI - USB to TTL module or RS-232 module - RS232 to TTL <-- if your computer has a 9 pin serial out. For power, 3 battery of 1 1/2 V in series = 4.5 V ( AA, AAA, C, D <-- your pick ) will power the Arduino chip ( I did that and it work just fine ) .

Please note, when you program the chip, using a USB -TTL, disconnect the power going into the Arduino chip / circuit, the computer USB will provide the power. When using the RS232 module, keep the power connected to your Arduino / chip.

My 2 cent

22pF for the xtal, not 22nF
dipmicro has all the parts really inexpensive, except the bootloaded atmega

They (dipmicro.com) also recently added RGB LEDs at reasonable prices plus they have TLC5490 to drive them :slight_smile:

Here is my lcd back pack:

Why 16 MHz? Why not 20 MHz for 20 MHz-capable chips? Does that make the rest iffy?

GoForSmoke:
Why 16 MHz? Why not 20 MHz for 20 MHz-capable chips? Does that make the rest iffy?

Maybe that wastes power if 20MHz is not needed and also that needs stable voltage of greater than 4.5V, which you can't get from 3 AA batteries. 16MHz can probably be safely run at that voltage. See fig. 28-1 on the atmega328 doc.

Sorry CrossRoads for my typo. I mean 22pF, like you said.

I did try to run my Ardiuno chip with 4.5 V using 3 AA batteries.... work fine - a temporary solution . But if I need to build into a permanent project, I will add a 7805 reg ( with input cap and output cap ) and a heatsink, that way, it will work fine.

I would rather just use a 5V regulated wallwart switching suppy, skip the 7805 and all that heat.
http://www.dipmicro.com/store/DCA-0510
Lot of accessories?
http://www.dipmicro.com/store/DCA-0520

That is a good idea for a PSU. I will keep that in mind. ( I will shop locally to see if they have it - SAYAL Electronics )

dipmicro is just over by Niagara Falls, with really cheap shipping costs.

CrossRoads:
dipmicro is just over by Niagara Falls, with really cheap shipping costs.

They are located in Canada and bring US destination packages into US to ship so if you are in either US or Canada, you will save on shipping. I ship to Canada once in a while, it's not cheap for those packages to cross that boarder by themselves. Dipmicro has everything at incredibly low price, except that they don't have bootloaded ATMEGA328P. The store owner must be a PIC guy, lots of PIC's.

To bad about Dipmicro not having bootloaded ATMega328P. I order mine at http://www.hvwtech.com/products_list.asp?CatID=90&SubCatID=266&SubSubCatID=274. The chips work fine. I also order my FTDI and USB mini from them. They also carry the 28 pin ZIP, that I will use in my homemade board to program the Arduino chips with the sketches. It take a week to received the items from them. ( Calgary - Toronto ) @ $10 shipping cost.

Easy to bootload blank chips with westwf's optiload program tho. I stocked up some last time Newark had low prices.
Currently $3.42 for 10.
$3.31 for 10 at Mouser

$5.50 for 1 seems high.

So even in Canada, the Tech resellers are consolidating:
"In 2007, HVW Technologies was purchased by Solarbotics Ltd., another Calgary-based electronics company specializing in hobby robotics. Both companies are now operating out of the same facility under different banners, but the same, excellent Solarbotics Ltd. infrastructure!"

Techone:
They also carry the 28 pin ZIP

So you meant DIP or ZIF? :wink:

Techone:
I check your site, Nice work by the way.

Thanks Techone!

Techone:
You say you can not use an auto-reset feature when your program the Arduino using the RS-232. (...)

Well, that's not what I say :). What I say is that the board published there doesn't support the auto-reset feature. Meanwhile, in my board I have actually soldered a cap and resistor to add it (since the bootloader shorted the start time, it became very difficult to do the manual reset at the right moment).

A breaduino is, of course, the simplest of the Arduinos; but even if you can use it a final product, the breadboard is much more expensive than, say, an EDuino PCB, and doesn't provide not even nearly the same reliability. You can build breaduinos on protoboards - same reliability just a bit bigger.

CrossRoads:
Easy to bootload blank chips with westwf's optiload program tho. I stocked up some last time Newark had low prices.
Currently $3.42 for 10.
$3.31 for 10 at Mouser
http://www.mouser.com/ProductDetail/Atmel/ATMEGA328P-PU/?qs=sGAEpiMZZMtVoztFdqDXO6rEZqxeooRg
$5.50 for 1 seems high.

If you live in US-midwest and don't mind getting 25 of them:

$3.12 each for 25 pcs.

Even cheaper. The 25 that I bought, which seems to take forever to use up, did not last very long. They all got their phi-panel firmwares and were shipped out. Only 5 are left. Besides westfw's optiloader, I also recommend xloader to upload hex sketches. Way faster than arduino IDE and compact size. Perfect for in the field reloading sketches or firmeware updates, which is what I do with it.