Monday, September 24, 2012

Raspbery PI - Presentation to Amateur Radio Clubs


On Wednesday May 15, 2013 I presented an updated version of the Raspberry Pi presentation to the Quinte Amateur Radio Club (QARC). You can view or download a PDF of the presentation from here.

You can buy one over the counter from Qkits in Kingston, or mail order from Element 14 (make sure you select country Canada, it then ships customs cleared).

To get started, see here for the hardware and sw setup, and here for more details on the OS.  The official Raspberry PI site, wiki, forum are the place to start as things are moving fast, and information gets out of date fast.

I also have a number of blog posts on things I have done with it (some of which may actually be outdated, as new and better ways to do things are emerging all the time)

A number of the PERC and QARC members have purchased rPIs and we have started a SIG mailing list. Contact me at va3ep@rac.ca if you want to be on the list.

On Wednesday October 4, 2012 I repeated this presentation at the meeting of the Kingston Amateur Radio Club where there was also a lot of interest.

On Thursday September 20, 2012 I made a presentation and demonstration of the Raspberry PI to the Prince Edward Amateur Radio Club.




 


Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.



Sunday, September 23, 2012

Raspberry PI - how to find out IP address

A reader writes:

> How do I determine the IP address of my Pi? 

In a shell type:

     $ ifconfig

If you type

     $ apropos something

it will list all applicable commands, i.e.

    $ apropos network

it would have listed ifconfig (but it might not have been obvious that
ifconfig with no argument will display the current network interface
conditions without changing anything). For detail on any command

    $ man ifconfig

will display the manual page.



Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.

Wednesday, September 19, 2012

Raspberry PI - now supports OVERCLOCKING


If you are not checking out the Raspberry Pi main website, you miss out on cool stuff like this:




Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.

Tuesday, September 18, 2012

Raspberry PI - Lots of ways to interface to the GPIO pins


By installing the appropriate LINUX drivers and Software Modules (more on this in a later post, I hope), the rPI can communicate on the General Purpose I/O Pins (GPIO) with a LOT of different protocols.

At least one rPI LINUX disto from Adafruit has support for SPI, I2C, and one wire already built in.

Just be aware that the rPI GPIO pins are 3v3 level, and not buffered, so you have to be careful in interfacing to them, see this post for more information.


Parallel (on rPI 3v3)
http://en.wikipedia.org/wiki/Parallel_communications
up to 17 wires + Gnd
up to Mhz
Many devices (LEDs, switches)


Serial Asynchronous - Start/8 Bit/Stop  (on the rPI, level is 3v3, not RS-232 level
http://en.wikipedia.org/wiki/RS-232
2 wires + Gnd (or more)
115,200 bit/s and above
Many devices (especially legacy)


1-Wire (on rPI 3v3)
http://en.wikipedia.org/wiki/One_wire
1 Wire + Gnd
up to 16.3 kbit/s
Devices
     Memory
     Thermometers
     Clock / Timer
     Digital Potentiometer
     etc.


I2C (on rPI 3v3)
http://en.wikipedia.org/wiki/I2c
2 Wires + Gnd
      Serial Data Line (SDA), Serial Clock (SCL)
Up to  5 MHz
Devices
     SPD EEPROMs on SDRAM, DDR SDRAM, DDR2 SDRAM, NVRAM
     DACs and ADCs.
     intelligent speakers.
     OLED/LCD displays
     hardware monitors and diagnostic sensors
     real-time clocks
     etc.


SPI - Serial Peripheral Interface Bus  (on rPI 3v3
http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus
4 wires + Gnd
     SCLK: serial clock (output from master);
     MOSI; SIMO: master output, slave input (output from master);
     MISO; SOMI: master input, slave output (output from slave);
     SS: slave select (active low, output from master).
Not limited to any maximum clock speed, typical 1–100 MHz
Devices
     Sensors: temperature, pressure, ADC, touchscreens, video game controllers
     Control devices: audio codecs, digital potentiometers, DAC
     Camera lenses: Canon EF lens mount
     Communications chips: Ethernet, USB, USART, CAN, IEEE 802.15.4, IEEE 802.11
     Memory: flash and EEPROM
     Real-time clocks
     LCD displays, sometimes even for managing image data
     etc.





Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.

Saturday, September 15, 2012

Raspberry PI - Keeping Rasbian Up To Date


Updated Sep 18, 2012

I enjoy reading posts in the Raspberry PI Forum. There is always something there that is interesting, and a lot of useful tips.

In This Post was a tip to keep your Rasbian LINUX up to date with latest patches as "as fixes are added every week (even daily)".

Assuming that your rPI is connected to the Internet, as the command prompt, type

      sudo apt-get update
      sudo apt-get upgrade
      sudo reboot


and you will have all the latest updates. I did this a few weeks ago, but when I just did it I have 127 packages updated. So it looked like you need to do this regularly. There may be a way to do this automatically, but for this type of device, IMHO that would not make sense.

As reader Dave noted, this can take a LONG time, so do the upgrade when you don't want to do anything else for a while.

Also, during the upgrade there is a prompt about the file /etc/skel/.bashrc being modified (that is a file used to create individual login scripts for each account that gets created - kind of an account level AUTOEXEC.BAT). As I did not modigy it, then I assume it was one of the packages that I installed that did. The "right" thing would be to make a backup (in another term session, for example) and then after the upgrade to compare the new and old and merge the changes. May just be easier to re-install any package that breaks.
LINUX gurus know this stuff already, but this is a good tip for the LINUX newbie. See this reference for more info on the Debian apt command.



Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.

Wednesday, September 12, 2012

Raspberry PI - Python 2 and 3 - Print, Serial, GPIO

As a Python newbie, I am stumbling upon things about it as I go along.

One of the things that I have discovered is that in Python 2, you can import the serial function that is used in Python 3 using the following:

from __future__ import print_function

then you can use the Python 3 print function in Python 2 programs

print(*args, sep=' ', end='\n', file=None)

From what I am reading (I am a real Python newbie) for the beginning programmer the biggest difference between 2 and 3 is the the way print works - in 2 it is a statement, in 3 it is a function.


Also, it looks like you can install the important Serial and GPIO support modules to work under Python 2 or 3. I assume that the module install routine detects what version it is being installed for and does the "right thing".

For Serial see: http://pyserial.sourceforge.net/pyserial.html

For GPIO see: http://code.google.com/p/raspberry-gpio-python/downloads/list

I have not really experimented with this yet, but it would mean that you should be able to do most common programming using Python 3, which from what I am reading, is the preferred version to use.

Apparently the only real reason to use 2 is if there is some module you absolutely need that just does not work in 3 (yet).



Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.

Thursday, September 6, 2012

Raspberry PI - New Board Revision / Make in UK


Interesting news at http://www.raspberrypi.org/


1) A New "Revision 2" board, with some subtle and not so subtle changes is now in production. Most notable changes:
  • Mouting holes
  • More power to the USB ports
  • Change to GPIO pin mapping (apparently will make sw development a bit more challenging to work for all rev boards)
Also some other things, see the link above for details.


2) The board will now also be made in the UK (as well as still in China, I assume)

Again, more info on the link above.



Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content.

Saturday, September 1, 2012

Raspberry PI - another "free" option for connecting to GPIO Pins


I just received a Pi Cobbler Breakout Kit for Raspberry Pi from Adafruit.

It looks great for connecting the GPIO Pins to a proto board while minimizing the likelyhood of shorts.

By the way, check out their site as they not only have a lot of Raspberry PI stuff, they have TONS of other interesting products.

After I had order the "Cobbler" I thought of something else that might be useful for connecting to the rPI GPIO header and require no soldering / heat shrinking like what I suggested here.

If you see an old computer being "recycled" (more joy of junk), open the case and look for the wires that go from the front panel switches and leds and plug into the motherboard. You can see them hanging there in this picture. You can just cut them away from the front panel with side cutters, leaving the wires as long as you can. On the end that plugs into the motherboard, just pull them off, you will find these connectors will fit the rPI GPIO header pins exaclty.

Although most of the connectors are double, and would cover 2 pins at once, that is not a problem (even if you only need access to one GPIO pin). Just strip the insulation off of the end without a connector, twist tightly and insert into the propo board. Tinning the end with your soldering iron will keep it from fraying, just make sure that you use the solder sparingly and knock off any excess while still melted so as not to make the wire to fat to push into the proto board.


Eric Pierce VA3EP - See the Disclaimer in the Introduction

© Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", 1952-2099. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Eric Pierce and "VA3EP Amateur Radio And Other Geek Pursuits", with appropriate and specific direction to the original content