Arduino Forum

Forum 2005-2010 (read only) => Hardware => Development => Topic started by: kg4wsv on Mar 05, 2008, 01:53 pm

Title: Arduino serial with MAX232 or equivalent?
Post by: kg4wsv on Mar 05, 2008, 01:53 pm
Has someone done an Arduino serial board design that uses a true rs232 transceiver (e.g. MAX232) instead of transistors/capacitors/diodes?  I'd prefer a "single sided" design, to facilitate etching at home.

I've had trouble with circuits that use the transistor trick in the past, and prefer to avoid such circuits if possible.

-j

Title: Re: Arduino serial with MAX232 or equivalent?
Post by: adilson on Mar 05, 2008, 03:23 pm
I started doing a version with max232 three weeks ago, based on S3v3 version, but stoped. If you want one, I think I can restart it. In a preliminary view, it will be a little bigger than S3v3 (less than 1cm.).
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: kg4wsv on Mar 05, 2008, 06:32 pm
Has the s3v3 been posted somewhere?  A quick google didn't return anything useful.

I'm not opposed to doing the work myself, but I prefer not to reinvent the wheel.  :)

-j

Title: Re: Arduino serial with MAX232 or equivalent?
Post by: mellis on Mar 05, 2008, 06:43 pm
It just went up here: http://www.arduino.cc/en/Main/ArduinoBoardSerialSingleSided3
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Mar 08, 2008, 08:19 am
I've had a max232 based design sitting in the wings for a while (it's double sided though). Anyhow, relevant details are here (http://spiffie.org/electronics/archives/microcontrollers/A%20max232%20Based%20'duino.html).
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: kg4wsv on Mar 08, 2008, 02:49 pm
Nice.  Any plans to make boards or kits available?

-j

Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Mar 08, 2008, 04:01 pm
There can always be kits :) Back of the napkin says they'd run about $15-$20.

If anyones interested I can try to sneak a few onto next week's panel.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: kg4wsv on Mar 08, 2008, 04:15 pm
I'd take a couple of bare boards, or one kit.  I've already got components (except for the regulators and the short 47uF caps), so bare boards would work fine for me (I realize probably not for most folks, though).

-j

Title: Re: Arduino serial with MAX232 or equivalent?
Post by: nkcelectronics on Mar 10, 2008, 02:06 pm
I am moving to the MAX232 for the Freeduino Serial V2.0

I prototyped it and it works great... 100% reliable uploading sketches.  I can share the schematics and eagle files, if anyone is interested.  The signals (RX, TX, DTR) behave a little different from the USB based Arduino signals, but it is consistent to any other MAX232 based board.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Mar 10, 2008, 10:22 pm
(http://farm4.static.flickr.com/3139/2325224242_f4e43f59e7.jpg?v=1205209896) (http://flickr.com/photos/spiffed/2325224242/)

After finalizing the BOM, these are just waiting to join a panel. (Now I need to do real work so I have something justifying a panel :() The only strange component left is the 3.3V regulator (78L33) and the short caps.

Expect boards whenever they come back from the fab-house, and kits whenever the parts come in.

Actually, is there anyone who'd prefer I didn't use "Freeduino Serial"? There could be confusion with the existing (transistor or otherwise) Freeduino Serial boards.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: nkcelectronics on Mar 11, 2008, 03:35 am
I think Freeduino Serial is fine.  The version number should be V2.0 or superior, as the changes from V1.0 justifies the new version number and leave V1.x for enhancements to the transistorized boards.  I am working on my serial board based on MAX232 and I am calling it Freeduino serial V2.0, which I almost finished last week... but I think I will also add the 3.3V regulator, if you don't mind sharing the idea.

BTW, what PCB design software do you use to make those nice looking 3D images of the board?
Edited: Never mind... it is Eagle3D.  I tried it and it works great!
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Mar 11, 2008, 05:02 am
Quote
The version number should be V2.0 or superior, as the changes from V1.0 justifies the new version number

I think you're right, 2.x makes sense.

Quote
what PCB design software do you use to make those nice looking 3D images of the board

I use Eagle. The 3D mock-ups come from the Eagle3D ulp (http://www.matwei.de/doku.php?id=en:eagle3d:eagle3d) and POVRay (http://www.povray.org/). It can take some futzing to generate exactly what you're after, but it works. I find it most useful to uncheck "parts" in the Eagle3D dialogue and use it to generate PCB only renderings like these (http://flickr.com/photos/spiffed/2326185308/in/set-72157604095137577/). I know there's a Protel/Altium tool to do the same.

Quote
I think I will also add the 3.3V regulator

I used a 78L33, simply because I have them in inventory. Sadly there doesn't seem to be a standard for 3.3V regulators, the 78L33 is only made by ST. Other manufacturers make other regulators, and you may find a better choice for you; I found most to be pricier and require larger stabilizing caps. A different regulator may have a low enough drop out to run from the 5V rail though instead of Vin.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: nkcelectronics on Mar 11, 2008, 07:35 am
Quote
Quote
The version number should be V2.0 or superior, as the changes from V1.0 justifies the new version number

I think you're right, 2.x makes sense.

With Freeduino, it is important to add the name of the person / company making the enhancements to the board, so if two or more at the same time name a board "Freeduino serial v2.0", then the only way to distinguish one of the other is by the name (Fundamental Logic in your case).

Quote
Quote
I think I will also add the 3.3V regulator

I used a 78L33, simply because I have them in inventory. Sadly there doesn't seem to be a standard for 3.3V regulators, the 78L33 is only made by ST. Other manufacturers make other regulators, and you may find a better choice for you; I found most to be pricier and require larger stabilizing caps. A different regulator may have a low enough drop out to run from the 5V rail though instead of Vin.

I added a 78L33 and a cap to supply 3.3V to the header, but I will leave it as an option when I sell the kits, as not everybody needs the 3.3V.  I run it from the 5V rail, as the drop out is 1.7V for 78L33...
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: Daniel2 on Mar 11, 2008, 08:08 am
hey

I would even suggest something more specific, like "Freeduino Fundamental V2" or something like that.....
That way there can be  multiple serial boards, with less confusion. as we're basically talking about boutique versions, it makes sense to highlight the manufacturer name in the design.

D
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Mar 11, 2008, 10:40 pm
After much deliberation, these will be silkscreened as "Freeduino MaxSerial".
I've noticed most people seem to regard the NKC Electronics boards as the unofficial official Freeduinos.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: follower on Mar 12, 2008, 11:58 am
Quote
After much deliberation, these will be silkscreened as "Freeduino MaxSerial".

Before I got to the end of the thread I was going to suggest using Freeduino Serial Max. :-)

--Phil.

P.S. Followed by the "Gold" and "Pro" designators... :D
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: nkcelectronics on Mar 13, 2008, 12:28 am
Quote
After much deliberation, these will be silkscreened as "Freeduino MaxSerial".
I like MaxSerial.
Quote

I've noticed most people seem to regard the NKC Electronics boards as the unofficial official Freeduinos.

The Freeduino spirit doesn't allow the existence of an official version... maybe my boards are some sort of de-facto standard in the Freeduino world, because I am part of the team that created the first prototype releases, but there are many variations showing up... but yes, all the blames for the bad designs, problems, etc are almost all mine.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: nkcelectronics on Mar 28, 2008, 10:47 pm
Freeduino serial V2.0 is ready.  It uses a MAX232 or compatible IC and has onboard 3.3V regulator (will be optional in the kits) using a 78L33 and a cap.  Will test for a couple of more days and will be available as kits.  So far, I tested uploading aprox 10 example sketches with 100% success.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Apr 09, 2008, 10:55 am
MaxSerial boards (http://spiffie.org/kits/maxserial) are now in stock.

Check out the directions (http://spiffie.org/kits/maxserial), or just jump right to the WebStore and buy a kit (http://store.fundamentallogic.com/index.php?main_page=product_info&cPath=56_58_62&products_id=121).
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: tvdbon on Apr 14, 2008, 11:27 am
is there a singe sided arduino board with the max232 available anywhere? I'd like to try and etch one but I'd like it to work with the max232 chip
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: spiffed on Apr 14, 2008, 04:13 pm
You may have better luck than me, but I couldn't fit the MAX232 and associated bits into the footprint of even the much larger SS-Serial board. Even double sided the board still has a few vias.

If you can fit it onto a reasonably sized single sided board, I think we'd all love to hear, otherwise, I sell just the bare board (http://store.fundamentallogic.com/index.php?main_page=product_info&cPath=56_58_62&products_id=124) for exactly this reason. If you'd like a starting point, the board/schematic are available at the end of the directions (http://spiffie.org/kits/maxserial).
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: purgedsoul on Aug 13, 2008, 03:18 am
Quote
I started doing a version with max232 three weeks ago, based on S3v3 version, but stoped. If you want one, I think I can restart it. In a preliminary view, it will be a little bigger than S3v3 (less than 1cm.).



Hi Adilson,

I am interested in a single sided Severino with Max232. It would be nice to see a different type of Severino. Looking forward to this. :-)
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: purgedsoul on Aug 30, 2008, 06:04 pm
I would like to share to the community my single sided Max232 Arduino clone. This is based on the single sided board done by Adilson. Made it as a learning experience using Eagle. While waiting for Adilson's version, got to thinking why not try to create one. So after a few weeks of tinkering with Eagle finally got it made. Cheers!

(http://img329.imageshack.us/img329/5259/img2741du3.jpg)

(http://img329.imageshack.us/img329/7756/img2740zx6.jpg)
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: mellis on Sep 01, 2008, 09:12 pm
purgedsoul: very cool!  Is it working well?  Can you post the Eagle files somewhere (if you haven't already)?
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: purgedsoul on Sep 02, 2008, 02:34 am
Thanks Mellis! Sorry forgot to attached the Eagle files. but here it is.

http://www.sendspace.com/file/6s8mq0

The clearance of trace between the leads of C5, C8 (Vin Trace) is very fine, I have to score it since when I did the toner transfer, it somehow merged with the pads of C5. :-( It is also true with DB9 pin 4. I will have to make some modification to this.

Yes, it is working, I have tried uploading sketches to it and it worked fine, also the autoreset worked. I also uploaded the bootloader using the ICSP pins on the board, but have to desolder LED L (on pin 13) first.

I am currently running a sketch on it making it as a thermometer using LM35 with output routed to a 3310 LCD (PCD8544). :-)
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: adilson on Sep 03, 2008, 03:13 am
Nice Job PurgedSoul.

I'm very busy taking care of my newborn baby, so I stopped the development of MaxSeverino.

Good luck.
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: purgedsoul on Sep 03, 2008, 11:42 am
Quote
Nice Job PurgedSoul.

I'm very busy taking care of my newborn baby, so I stopped the development of MaxSeverino.

Good luck.


Thank you Adilson! and Congratulations! :)
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: adilson on Sep 04, 2008, 05:45 am
Thanks, PurgedSoul! ;D
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: galish on Oct 23, 2009, 03:26 pm
anything new about duemilanove ?
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: galish on Oct 23, 2009, 03:29 pm
anything new about duemilanove ?
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: galish on Oct 23, 2009, 03:32 pm
anything new about duemilanove ?
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: iparuk on Jun 03, 2010, 08:28 pm
How u get the silkscreen on the board, in ur design i see like a pologon on the bottom layer but it just print jaggered lines, how do i change it to fill in the whole thing... thanks in advance
Title: Re: Arduino serial with MAX232 or equivalent?
Post by: pedrodv on Aug 03, 2010, 08:39 pm
really nice work purgedsoul  ;)