More from my class- Propeller Board design

Martin Hebel · 2007-11-02 05:51

My class also spent some time laying out PCB's for the Propeller.· We wanted a board that:
- Was inexpensive (Demo boards are expensive to replace)
- Had some higher level I/O (video/mouse or Keyboard)
- Could be plugged into a breadboard for larger circuits than the demo could support (ran a lot of jumpers this semester)
- Could use the +5V feature of the USB-CE5 or a PropPlug with 9V supply (battery terminals would be nice, but too much space).
- Small size, but since we don't have good surface mount working tools, we decided to place some components on the back and stick to the DIP 40·(since it would be plugged into a breadboard) - Measures 4" x 1.85"
-Socket for Prop and for the EEPROM so programs could be switched without reprogramming.
-Power LED
-A 'debug' LED.

Since I'd like to give one of these away to high school's/community colleges·we visit on recruiting trips with some pre-programmed cool stuff on it (and advertising), I though it would be good to have a small solder area and terminal block area (and they could be chopped off if not needed to reduce size).

Attached is the result of our planning, I also have a VGA version I'm still debating on the added cost over. The composite video version with parts will be about $29, something low enough I can ask students to buy parts for in coming semesters.

And... it works! Yay again.· Only have an ugly prototype board now, will post a final product pic when built.

How much fun can one person handle?

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StampPlot - GUI and Plotting Software
Southern Illinois University Carbondale, Electronic Systems Technologies

Post Edited (Martin Hebel) : 11/2/2007 6:01:54 AM GMT

OzStamp · 2007-11-03 07:12

Hi Martin

This is what we have come up for the EDU market here.
This is the MotherBoard of the whole system.
There are effectively 11 small PCB's in a panel that make up
a really neat system..

See pic attached

Ron Melbourne OZ

deSilva · 2007-11-03 08:09

Everybody is doing the same, I think.

@Martin: Your board can be produced in China for $7 starting from 20 pcs, 100 pcs will be cheaper; package and handling negligeable.

A main concern in educational courses is the time spent for building specific things up. Breadboarding is fine, but you cannot always add the Propeller including EEPROM in time and error-free. The SpinStamp would be perfect for many applications but is prohibitively priced.

I am on the "breadboard module trip" at the moment, devising "stick-in" modules, so you can assemble things with "standard parts" within seconds; the application circuit is on the breadboard and the - generally - more expensive parts can temporarily be recycled without harming the later re-use of that specific circuitry...

Power supply: After several different approaches, we now use 4x1.2V reachargeables ("AA" - which come in an extremely wide price range -
I had a student who used even monocells ("D") with 7Ah capacity

but that was not really cheap) . They provide 5V within reasonable range when needed (LCD Display, Keyboard,..) and can economically be regulated to 3V3, which will be needed for some applications with this precision. There is also an increasing offer for 5V wallwards, used for USB-Hubs, ...

Nick Mueller · 2007-11-03 10:21

> @Martin: Your board can be produced in China for $7 starting from 20 pcs, 100 pcs will be cheaper; package and handling negligeable.

As I think that you are from Germany:
Do you have a contact address? Preferably a broker here in Germany as I don't want to mess around with the Chinese directly.
I have to let make a run of several boards and PCB-Pool is getting too expensive with two-sided + solder stop (both sides different) + silk screening.

TIA
Nick

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Never use force, just go for a bigger hammer!

The DIY Digital-Readout for mills, lathes etc.:
YADRO

OzStamp · 2007-11-03 10:22

Hi All

Just a little history ..
When we started selling the Parallax stuff here in OZ there was only the BS1-IC and the BS1 chipset
We at the time had a StampBus modular system.. we sold bucket loads of them.
Ken Gracey (Parallax) at the time via fax or phone told us .. we have got something really awesome coming
it will be called a BS2-IC .. a year later we made a development system based on the BS2-IC module.
It had leds on it some ic socket for 8 pin dippers and a GAL chip that could mutiplex 16 ins to 4 I/O lines...
I think we were the only idiots in the world to have a development board with a 3M zif socket on it..
Again we sold bucket loads of them to schools and also engineering people..people loved that expensive Zif socket
Those were the day's ...cheap stuff at the time came from Japan... now it is our friends in China.
We are just below there so maybe we are next..

And now we have the Propeller....what will be next .. TurboProp2_Bus system..

Cheers Ron Melbourne OZ

Post Edited (OzStamp) : 11/3/2007 10:27:18 AM GMT

deSilva · 2007-11-03 11:00

Nick Mueller said...
Preferably a broker here in Germany as I don't want to mess around with the Chinese directly.

There is the suspicion that many low cost suppliers of PCBs already have them made in China without telling directly. This comes closest to what you call "Broker". The price will double in that cases (still cheap).

Chinese: Worked at least once

PCBCART - PCB supplier from China
URL: http://www.pcbcart.com
Email to: sales@pcbcart.com
Phone: +86-571-87013819

An unexpensive German manufacturer
www.multipcb.de/ger/sites/pool/index.html

Nick Mueller · 2007-11-03 11:23

> An unexpensive German manufacturer www.multipcb.de

I once tried it with them. They only want to deal with companies. :-(

pcbcart is looking promising! I'll try it with them.

Thanks!
Nick

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Never use force, just go for a bigger hammer!

The DIY Digital-Readout for mills, lathes etc.:
YADRO

rjo_ · 2007-11-04 16:54

Martin,

I understand about the cost of the demo board... but shouldn't that be an expense for the student? The greatest gift you could give them would be to make them purchase a demo board... lasting value and more fun than a barrel of monkeys. AND if a student really didn't really want to keep it, there will be a campus market for selling them. The actual cost would then be the interest on the money for one semester minus the depreciation... which should equal the cost of postage minus all taxes plus the value of the accumulated objects, documentation, samples of all circuits, and copies of all tests, all of which could be burned to disk and offered as a part of the re-sale.

Rich

parts-man73 · 2007-11-04 17:18

excellent point rjo_ in fact, I had bought a boe-bot a couple year ago from someone on ebay. They said that they were a student who bought the boe-bot for a class, he used it for one semester and was then selling it.

Compared to the price of most textbooks nowadays, a Demo board wouldn't be too much to ask.

One suggestion as you go forward with your own design, perhaps add a SpinStudio like connector. That way your students could easily plug in any modules that I currently offer. I have a new module that I haven't announced yet. A blank Prototyping card, that might prove to be useful. It has some prototyping area, and access to 3.3V, 5V, VSS, 8 IO pins and I2C. Then your students could solder together some small projects, plug in when needed, or swapped with a different project card in a moments notice. Attached is a picture of this new prototyping card.

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Brian

uController.com - home of SpinStudio

PropNIC - Add ethernet ability to your Propeller!

SD card Adapter

Martin Hebel · 2007-11-04 21:20

Sorry, I've been out of town for a few days.

Nick & DeSilva: I'm from the U.S., for PCB's I use ExpressPCB.com, with qty of $50 be about $8 a board.
As to power, they can use the 2.1mm wall ward, USB from the CE-5, or wire on battery clips.

Rich: The students are so loaded down with tution and fees and books which increase every year, I want something inexpensive they can replace/fix. This is an elective course, so when I start increasing costs, my numbers drop [noparse]:)[/noparse] Also, as mentioned, since our enrollment is down, we visit a lot of school to highlight our program, and if we can leave one behind with a cool program and our name on it, all the better.

I've also got some workshops coming up for educators and such, and something they can take home (at least the PCB) will help out some.

And it's been a good experience for them to help design a board [noparse]:)[/noparse]

Thanks for the feedback!

-Martin

rjo_ · 2007-11-06 16:09

Martin,

I've been thinking about your comments... particularly about the enrollment issue. One of the nice things about SIU is that it is out in the middle of no-where. Parents like that. The hard part is that SIU is a long way from the primary educational markets in Illinois. AND if you recruit Illinois students, you aren't bringing any new money into Illinois... we are just recycling the same old dollars.

Finding a safe place to have children educated is a global problem. Having a college age daughter, I just recently looked at what is available in Illinois and the opportunities are astounding. Things really have improved over the last 20 years. There is a natural place for just about any kind of student somewhere in Illinois.

The Propeller has all of the look and feel of becoming a potential windfall for developing countries. I am looking forward to seeing you come to a high-school near me... but I would also think that your department would be a prime candidate for full internationalization. There are big bucks available for educating foreign students.
You would be a very good international ambassador for SIU, sort of a 21st Century Johnny Appleseed.

Many countries actually pay the freight... getting on the list is all it would take.

Foreign students should be flocking to SIU, but SIU needs to go to them... they don't know SIU exists.

Rich

More from my class- Propeller Board design

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