

Gertboard expands the Raspberry Pi’s GPIO pins - wiradikusuma
http://www.raspberrypi.org/archives/1734

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FrojoS
> Gertboard is packaged as a kit. It doesn’t come preassembled; you will have
> to solder it together yourself.

I hope it won't take to long until there will be pre-assembled ones, too. For
an open source design, all you need is someone who invests some money to get
the board assembled in China and then sells it in a web store.

Here is an example, to show how affordable assembling low quantities of boards
in China has become. For one of our designs, buying all the parts online in
the US or Switzerland, was about $150. If you buy about a dozen of them in
China, they are about the same price point. But then, they are already
assembled according to our design! Once you buy around one hundred, you save
considerable money. In our case, the offer we got is about $100 per board (33%
savings!).

The lower the transaction cost, the better. If you think soldering has minimal
transaction cost, compare the price of a soldering station with a Raspberry
Pi.

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jberryman
Not to contradict your point, but this board should be easy to assemble as a
first project with an investment in <$20 of soldering equipment and supplies.
So I'd encourage anyone who's interested in this but new to electronics to
head over to sparkfun and just dive in and see how you like it.

~~~
veemjeem
Easy? Not so... this is not a beginner's kit, there are surface mount
components, and if this is your first time soldering, it's gonna be a rough
day.

Sparkfun does a really good job of making their kits easy. If you look closely
at them, the boards that require diodes and electrolytic capacitors have a
picture printed on the pcb that make it really obvious what the polarity is.
The gertboard pcb doesn't have any of these. If you solder a led backwards,
you're SOL. So if you haven't seen a diode or led before, you probably
shouldn't pick the gertboard as a first project.

You can buy the arduino as a kit, but most people who are just starting out
with electronics will get one prebuilt so they don't accidentally stick their
atmega chip in backwards.

~~~
tcdent
I don't see anything but through-hole components here, and I don't think
anyone would encourage a beginner to dive into a surface mounted design as
their first project.

[http://www.element14.com/community/themes/images/raspberrypi...](http://www.element14.com/community/themes/images/raspberrypi/gertboard_400straight.gif)

~~~
veemjeem
That's because your picture is too small to see the surface mount stuff :-)

See this larger picture:

[http://www.raspberrypi.org/wp-
content/uploads/2012/08/image0...](http://www.raspberrypi.org/wp-
content/uploads/2012/08/image002.png)

Or read the assembly manual where they teach how to solder surface mount
components. There's a bunch of resistors & capacitors all over the board that
happen to be surface mount.

[http://www.element14.com/community/servlet/JiveServlet/downl...](http://www.element14.com/community/servlet/JiveServlet/downloadBody/48916-102-1-256003/Gertboard_Assembly_Manual_Rev1.1_F.pdf)

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georgeecollins
While I think this is cool, I am not really sure what the advantage is of this
over a bunch of micro controller cards that you can connect with a USB. There
are a lot of different ones available and you can get them per-assembled or as
kits.

If you are waiting for this to control things with your Raspberry PI, I think
some choices already exist.

For example: <http://www.societyofrobots.com/axon_select.shtml>
<http://adafruit.com/products/849>
[http://www.parallax.com/Store/Microcontrollers/PropellerDeve...](http://www.parallax.com/Store/Microcontrollers/PropellerDevelopmentBoards/tabid/514/CategoryID/73/List/0/SortField/0/Level/a/ProductID/748/Default.aspx)
[http://www.parallax.com/Store/Accessories/MotorServoControll...](http://www.parallax.com/Store/Accessories/MotorServoControllers/tabid/160/ProductID/595/List/0/Default.aspx?SortField=ProductName,ProductName)
[http://www.parallax.com/Store/Microcontrollers/PropellerDeve...](http://www.parallax.com/Store/Microcontrollers/PropellerDevelopmentBoards/tabid/514/CategoryID/73/List/0/SortField/0/Level/a/ProductID/817/Default.aspx)

That's just a fraction of what is out there. And to repeat, I think the
gertboard is cool. But if you are waiting on it to control things, you don't
have to.

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sean-duffy
To be honest, I think if you're a programmer/developer looking at the
Raspberry Pi as a gateway to basic electronics, you'd barking up the wrong
tree and would be better off with one of the Arduino boards. With the Arduino
you have plenty of resources, and the convenience of only needing the Arduino
IDE and a USB cable to upload your program to the micro-controller. The
Arduino platform can do a lot in terms of reading sensors and controlling
circuits, and if that's all you want to do then a Raspberry Pi is far more
than you actually need, and much more expensive than an Arduino too.

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ricardobeat
Just get a teensy[1] board, and hook it up to the Rasperry Pi.

I'd like to know what kind of stuff you can do with the GPIO pins directly on
the Pi, via /sys/class/gpio. Are they just digital (0,1) or they can read
voltage levels too? (electronics newbie here)

[1] www.pjrc.com/teensy/

~~~
veemjeem
they are just digital (0,1). you need a A/D converter if you want to read
analog signals.

Here's a tutorial on hooking the raspberry pi with one of those chips to give
you analog input: [http://learn.adafruit.com/reading-a-analog-in-and-
controllin...](http://learn.adafruit.com/reading-a-analog-in-and-controlling-
audio-volume-with-the-raspberry-pi/overview)

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StavrosK
This is semi-offtopic, but has anyone found a good powered USB hub on dx.com,
that can power the RPi and peripherals? I'm tired if it not having enough
power to run wifi, or mobile internet, or anything else I put on there.

I'm in Greece, so dx is pretty much the only site that will ship cheap stuff
to me, but if anyone has another recommendation for a good hub, I'm thankful.

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option_greek
I was really looking forward for something like this. I hoped the price would
be a bit low though.

~~~
wiradikusuma
Probably this link can help <http://elinux.org/RPi_Expansion_Boards>

What I'm looking for is a step-by-step field guide for "interacting with real
world" for programmers with zero experience in electrical engineering.

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franzus
Yeah, I know what you mean. There's not much information about "electronics
for software guys". Every resource I could find was "the other way around":
Programming for electronics guys.

There were some promising videos on youtube but it all boiled down to: "Here's
this simple circuit. <no explanation about the circuit> Now to the hard part:
FOR loops. <30 minutes about for loops and basics of C syntax>".

I guess this would be a great topic for the pragprog-guys. If they'd
commission such a book I'd buy a dozen copies ;)

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alinajaf
> There's not much information about "electronics for software guys".

Interesting you mention this, I've been getting into microcontroller
programming for the past year or so and I've also found this to be the case.

I'm thinking of putting together some tutorials that focus more on the
electronics side of things. Additionally the programming would be a bit less
offensive to us (i.e. where possible tidied up into libraries instead of splat
out into one big sketch file). Do you think there might be a lot of interest
in something like this?

For arduino, getting set up in vim and working with ino (instead of the
arduino IDE, which is extremely useful but fugly as hell) was the first big
hurdle.

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wiradikusuma
please do, but please approach from software programmer perspective (please
read my other comment in this thread).

i think it's like OOP programmers trying to learn functional programming, you
need to bridge with similar concepts so it's easier to grasp.

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medinismo
has anyone bought/read/use the paraprog guide for raspberry py at
pragprog.com/book/msraspi/raspberry-pi? I would like to get started and this
book seems to be the only viable starting guide

~~~
veemjeem
I don't think you need a book to learn how to use a computer. You just plug it
in and go.

~~~
alexchamberlain
Have you seen some of the questions we are getting at
<http://raspberrypi.stackexchange.com/>?

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medinismo
precisely!

