Pumping Station: One

Monday Dec. 3rd. is back-to-basics night at NERP. In Part 1, Carl
Karsten and Bonnie King will give an introduction to Python programming
for novice programmers. The target will be the Raspberry Pi, and the
focus of their teaching examples will be on input/output to simple
hardware. In Part 2, yours truly will demo control of output devices
including simple circuits for interfacing electronics to
electro-mechanical devices.

Find us here…
http://www.meetup.com/NERP-Not-Exclusively-Raspberry-Pi/

-Ed

NERP October 22 Summary

Last nerp, Drew got things going with another well produced demo of the Raspberry Pi doing hardware i/o. In keeping with the spirit of the season he and Bonnie King put together a network controlled musical multimedia Jack o’ Lantern that blinked and played mp3′s through browser interaction. There are lots of ways of doing physical i/o though an internet link. To my untrained eyes, the high points of Drew’s and Bonnie’s approach included

• Python on the RPi

• On the Rpi is the bottle.py framework which provides a small, simple (so they say) web server for people who make stuff http://www.marginhound.com/bottle-py-resources/

• ajax to help push the data back and forth between the web page and server
• the RPi gpio module for reading switches and turning on and off the lights
• the python thread class for allowing the RPi to blink the lights without stalling the program
• a hook to control mplayer to play the sounds.

Check out Drew’s full write-up on his Element14 blog http://www.element14.com/community/groups/raspberry-pi/blog/tags/pumpkin_pi

Joe Walnes, known for his PiCrust http://picru.st/ adapter board, was our dark horse presenter. One of his other Raspberry Pi based projects is a coding environment called quick2web for people who are new to web programming* and also for rapid prototyping of web connected hardware control. Joe demoed web-slider:

• …a mobile web-app that contains a slider bar…
• …that communicates to a Python program via WebSockets…
• …that adjusts an LED bar-graph.
• Then point your desktop or mobile browser to http://[hostname]:8888/. Try multiple browsers for fun.
• https://github.com/joewalnes/raspberry-play/

The web interface allows multiple locations of interaction with the Raspberry-Pi through a browser. This is neat, but his main interest is in bringing a simplified, event driven programming model to beginning programmers. The demo made things like gui building and asynchronous hardware events look easy. When Joe’s quick2web environment takes off it will do for hardware-interactive web programming what the Arduino has done for microcontrollers and Libre development tools (gcc). I was pleased that Joe presented at nerp, and I hope he’ll do it again soon. Quick2web needs programmers. This is a worthy effort. Volunteer if you can!

*This is me.

Monday November 5

Ryan Pierce will show us how he is rewriting an Arduino 1-Wire library “…to be (mostly) non-blocking. My project is AC phase dimming with triacs while still reading temperatures… Each half of the AC sine wave is 8.333 ms. And reading a temp from 1-Wire is a 10 ms operation. So the new library allows me to start an operation, get a (nearly) immediate return, poll the timer for the AC to see if it is time to fire the triacs, go back to polling 1-Wire to see if it is time to bang a bit which should return (nearly) immediately, check the triac again, rinse, lather, repeat….. “

 John Dolecki will bring his Robot to this meeting. He says “Please don’t expect techno mumbo jumbo from me as my programming skills are on the beginner level. I’m sure once you are introduced to Microsoft Robotics Studio, the C programming will look familiar to you.

Let the Robot Apocalypses start here!”

Sounds great, John!

The next NERP (Not Exclusively Raspberry Pi) meeting will be at 7pm Monday Sept. 10th. See the NERP Meetup page for more information on location, meeting format, etc.

NERP is Not Exclusively Raspberry Pi, and this Monday’s meeting will also discuss Android and beer.

During fermentation beer must be kept at fairly precisely controlled temperatures. The required temperature varies with the stage of fermentation and other factors.

Any self-respecting beer temperature monitor would be accessible from the ‘net, and this one is no exception. Monday, Eric Stein will show Brewing Station: One’s  Raspberry Pi based temperature monitor and controller. Eric will show how the Python code and electronics work and discuss some issues around controlling temperature. Sampling the product will have to wait until Beer Church taps the keg.

The Desktop is DEAD, Long live the Desktop: The Android 4.0 miniPC

Jay will be doing a short walk-thru and talk about the user-land experience with the new Ricomagic MK802 thumb-drive-sized pocket-computer. Jay will be demoing android 4.x, Fedora, Ubuntu and/or puppy linux on the Ricomagic MK802. The Ricomagic MK802 is a $65 Cortex A8 1GHZ processor with 1GB of DDR3 Ram, 4 GB flash, wifi and a 500MH GPU (Mali 400) with HDMI video. The small computing landscape is changing fast, and the Raspberry Pi is only part of the story.

The bi-weekly NERP (Not Exclusively Raspberry Pi embedded systems) Meetup  focused on  serial i/o. Serial interfacing allows connecting “stuff” to a processor using a small number of wires. There are different ways of making serial connections to processors, and last night we talked about two of them. Drew showed how to implement I2C interfacing to several devices he had out for demo. I2C (I-Square-C) is a way of wiring smart devices like sensors, displays, and microcontrollers to a host computer. The Raspberry Pi has connection pins for I2C on the board and a kernel module for talking to I2C devices from user land. Ed quickly demoed a couple of examples of  UART serial technique with a Raspberry Pi running a login on a dumb terminal demo and an RS485 to PC interface on a Macbook. We’ll examine practical applications of these connection methods and others including SPI in future meetings.

The NERP description and meetup are at   http://www.meetup.com/NERP-Not-Exclusively-Raspberry-Pi/ . (It’s not necessary to use the Meetup signup to attend NERP, but it helps us anticipate how to set up the electronics lab for the number of attendees. Also it shows Meetup that people actually attend the meetings.) .

We’re looking for people who would like to show their work or lead a NERP-related discussion.  We’d especially like to hear about works in progress (i.e., unfinished), both in hardware and software.  Python, C, interfacing, non-Rasapberry Pi embedded systems, media, networking, and physical devices are particularly interesting.  Contact Ed (ed -> kineticsandelectronics – com) to schedule a day.

The next NERP (Not Exclusively Raspberry Pi) meeting will be at 7pm Monday August 27th. The new regular format of the NERP meetings is

1. a new user orientation (first session) at 6pm
2. The regular meeting (second session) from 7-8:30pm.
3. The after party which goes on until the building closes.

The orientation sessions help new users get their Raspberry Pis booted and quickly demo where the start buttons are in the operating system. The second session is a forum for talks, demos, free discussion, and questions. Subjects can be of general interest or advanced and highly focused. *

occidentalis – the black raspberry

The purpose of NERP is to promote discussion and exchange of knowledge and ideas. Interruptions and dumb questions are encouraged. The flow of a meeting can be deliciously chaotic.

I didn’t set out to take minutes at the NERP meeting last Monday, but there was so much good information flying around that it was hard to resist jotting some things down.

• Drew demoed many of the apps that come with the pi by default.

• Looked at Quake on the RPi. Learned about the Simple DirectMedia Layer (SDL) (“…a cross-platform, free and open source multimedia library written in C that presents a simple interface to various platforms’ graphics, sound, and input devices…”)
• Looked at /opt/vc where the broadcom videocore libs and utils live. Note to self: some of the utils look useful for low level tweaking at run time.
• Clarified the difference between Arduino and Rpi by running a blinky demo with the arduino hosted by the Pi
• Cortex M-series is the microcontroller family of Arms. There are <$20 ARM M4 boards.
• The logic level output lines are weak. Voltages are: USB = 5V, general i/o = 3.3V, HDMI = 1.8V.
• It don’t mean a thing if you ain’t got that adafruit clear box and breakout board.
• Everything is a file. How to do output in Bash:

echo “out” > /sys/class/gpio/gpio4/direction
echo “0” > /sys/class/gpio/gpio4/value
echo “1” > /sys/class/gpio/gpio4/value

• The video output problem… There are cheap 3.5” video screens (for car rear view cameras) on amazon
• From Jay: Demo of a Motorola dock for a phone for $55.   11.6” HDMI 1333 x 800. Works well with RPi.
• Watch ebay, amazon, China direct sellers for cheap $15 -to $50 HDMI to VGA adapters.
• In the initialization/setup tool set Pi to force HDMI so it doesn’t try to default to composite output at boot. It’ll get stuck there and won’t see the HDMI if plugged in later.
• Pi has undocumented connectors for CSI (camera serial interface) and DSI (display serial interface) Broadcom is planning a backpack HDMI rez camera for RPi
• The broken wireless driver problem is sometimes helped by using the Occidentalis v0.1 distro/mod from http://learn.adafruit.com/adafruit-raspberry-pi-educational-linux-distro/occidentalis-v0-dot-1
• All the cool kids are ditching plain Raspbian. Occidentilis (derived from Raspbian) is the one to have. It’s specifically for doing electronics. It has good support for SPI, I2C, one wire, and more WiFi sticks.  Black Raspberry – wheezy. Yes.
• Drew will make a wiki at PS:One (DONE)
• Computer vision is the killer app.
• That, and network services that interact with the physical world.

-Ed_B

*If you would like to show your work or lead a discussion on NERP, email ed at kineticsandelectronics dot com to set up a time.

NERP (The Not Exclusively Raspberry Pi embedded systems interest group) will meet Monday August 13th at 7:00pm. During the last meeting we talked about what the Raspberry Pi is and the nature of its capabilities. Jay showed a couple of videos to demo the HDMI output and described the process of setting up a new RPi. Drew Fustini took notes and has posted some comments and resources on the PS:One public list.

After the meeting, a few people stayed around to try some fun but not completely simple experiments with the RPi’s serial port. Using what I learned in the NERP serial port experiments, I made a RPi demo for to the Evanston Mini Maker Faire. The demo involved adding a 1984 Televideo 910 dumb terminal to a serial port on the Pi. The terminal is text only and displays characters as green on black. In addition to the normal gui session on the LCD screen, the RPi ran a separate user login on the dumb terminal. The LCD screen showed a video clip every 40 seconds, and the terminal showed a root login. Quite a number of people stopped by to check out the terminal and were surprised to learn about the Raspberry Pi’s role in making the demo run. More images of the Raspberry Pi at the Faire, and more technnical photos are at  http://kineticsandelectronics.com/RPi-makerfaire

On Monday 8/13, Drew will demo some of the basic applications that one might run on the Pi, and possibly discuss some issues around the subject of hardware interfacing. Open discussion is always welcome. An hour before the NERP meeting begins, Jay will be available to help anyone who has a RPi and would like help installing the basic operating system and apps. Jay starts at 6pm. The regular meeting is at 7pm.

The first meeting of the Embedded Systems But Not Exclusively Raspberry Pi Interest Group (ESBNERPIG or just “NERP”) will be Monday July 30th at 7:00pm. Embedded provides a place to look at trends in embedded computing outside of the basic serial port connected or standalone Arduino. Open standards, embedded interfacing, industrial systems, 32-bit MCU’s, operating systems, development tools, hardware design, form-factors, vendors, and the inevitable competitors of the Raspberry Pi are a few ideas for discussion.

July 30, Jay will start things off with a high-level tour of the Raspberry Pi SBC (Single Board Computer). Those who own a Pi and haven’t booted it yet [me], or who’ve booted their Pi and said “now what?” can watch the demos and follow along to get started and get ideas for things to try. For those who’ve had success with their Pis, we’d especially like to hear from you and see what you’ve got.

image

The move is finished. The old space has been stripped bare down to the paint — and even swept! All of  Pumping Station: One’s stuff is in the new building. Yippie! The new landlord is still using  a bit less than half the floor space. We’ve been assured that he’ll be moving his stuff out very soon. At present, the z-axis depth of the “collection” in the floor of the new space ranges from chest height to head height. The garage door in the alley of the old space went down for the last time at 12:04 am 6-18-12. Here are some random images I caught on my phone camera, mostly on Saturday and Sunday.

This workshop is part two of a two part intro to the Arduino being held at Pumping Station: One. Part 2 is for people who have a working Arduino setup running on their laptops. The emphasis in part two of the Arduino class is on programming. We’ll assume that you know where the different types of pins are located on the board, and that you can run the blink example. Ask lots of questions!

You will need to bring a laptop. You will need an Arduino. The best choice is Sparkfun’s “Flex” kit http://www.sparkfun.com/products/10174 If you don’t already have an Arduino, Pumping Station: One will loan you a Flex kit to use during the workshop session. Ask lots of questions!

images are CC BY-NC-SA 3.0 sparkfun.com

Workshop contents:

• The Arduino language: a simplified mix of C and C++
• Programming basics and interactive demos
• Experiment time to play with programming examples
• The Arduino language – special libraries
• Experiment time to play with library examples
• Arduino shields and i/o modules (demo)

Instructor: Ed Bennett
ed at kinetics and electronics dot com
kineticsandelectronics.com

Tickets are $25 and available  through Eventbrite.

This class is part one of a two part intro to the Arduino.  It’s an intro for people who have no experience with programming or electronics. Ticket information is at arduinointro1.eventbrite.com

You will need to bring a laptop. You will need an Arduino. The best choice is Sparkfun’s “Flex” kit http://www.sparkfun.com/products/10174 If you don’t already have an Arduino, Pumping Station: One will loan you a Flex kit to use during the workshop session. Ask lots of questions!

images are CC BY-NC-SA 3.0 sparkfun.com

Workshop contents:

• What’s Arduino?
• Installing the Arduino editor on your laptop
• Tour of the Arduino board and the Sparkfun “Flex” kit
• How to use a breadboard – hooking up sensors
• How to play with the built-in examples
• Experiment time to play with some examples
• Things you can do with an Arduino

Instructor: Ed Bennett
ed symbol kineticsandelectronics dot com
kineticsandelectronics.com