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All posts for the day May 17th, 2013

Mio for Raspberry Pi

Posted by epsilon on May 17, 2013
Posted in: Code, RPi-Arduino. Tagged: , , , , , , . Leave a comment

mio.py is “my” io library for Raspberry Pi. At present it is a kind of “hello world” program that demonstrates how work with one digital input, e.g., a switch, and one digital output, e.g., an LED. Below are (a) a photo of the Raspberry rigged up with a circuit managed by miO, (b) a description of the package, (c) some output on the command line, (d) a circuit diagram.

The (Python) code is at github.

(a) MIO RUNNING ON PI

mio-pi-2

(b) MIO: COMMAND SUMMARY

Suppose that LED is pin 17 and SWITCH is pin 23:

  • blink(LED, 0.1, 0.3) — blink LED, on for 0.1 second, off for 0.3 seconds
  • read(SWTICH) — read SWITCH: print 1 ON the first time it is closed, then the time it was held closed when it opens, then print 2 ON when it is closed the second time, etc.
  • control(LED, SWITCH) — control LED with SWITCH. This function is like read, except that the LED blinks when the switch is closed.

These functions can be invoked fromt the command line: (a) sudo python mio.py blink, (b) sudo python mio.py read, (c) sudo python mio.py control.

(c) SOME OUTPUT

pi@raspberrypi ~/gpio $ sudo python3 mio.py read
    1 ON
      1.09
    2 ON
      1.75
    3 ON
      0.13
    4 ON
      0.11

(d) CIRCUIT DIAGRAM

Let the switch have terminals A and B.

   A --- 3.3V

              |--- 1K resistor --- Pin 23
   B --- T ---|
              |--- 10K resistor ---GND

   Pin 17 --- LED --- 330 Ohm resistor --- GND

Installation in Red by Qureshi

Posted by epsilon on May 17, 2013
Posted in: Art. Tagged: , , , , . Leave a comment
Chang W. Lee/New York Times

Chang W. Lee/New York Times

And How Many Rains Must Fall Before the Stains Are Washed Clean?

This line in the famous poem by the Urdu poet Faiz Ahmed Faiz (1911-1984) is a verbal counterpart to the installation at the Metropolitan Museum of Art by Pakistani artist Imran Qureshi. See the New York Times article, May 16, 2013 by Ken Johnson.

Qureshi writes: “These forms stem from the effects of violence. They are mingled with the color of blood, but, at the same time, this is where a dialogue with life, with new beginnings and fresh hope starts.”

The exhibit runs from May 14 through November 3, 2013. Mr. Qureshi, who a created similar installation for the 2011 Shariah Biennial in the United Arab Emirates, is also know for his paintings in the style of 16-th and 17-th century Indian miniatures.

CLIPPINGS

(1) On war, from december71.wordpress.com

Perhaps, faiz has summed it up better than any other:

kab nazar meiN aaye gi be daaGh sabze ki bahaar
khoon ke dhabe dhuleiN ge kitni barsaatoN ke baad

When will we again see a spring of unstained green?
After how many monsoons will the blood be washed
from the branches?

Faiz Ahmed Faiz: On return from Dhaka: Hum Ke Thehray Ajnabi

(2) SIX URDU POEMS

Film: Meherjaan: A Story of War and Love

(3) Gunshots on Warm Spring Evenings

(4) In the world of print, it falls within the bounds of copyright law to quote small bits of text. Above, I have made a visual quote of Chang W. Lee’s powerful photograph. I hope that this will be viewed both as acceptable practice and become common one, helping to disseminate good images more widely in the same way that good text is disseminated.