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POpySerial works fine in Python interpreter, but not standalone
 

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  1. POpySerial works fine in Python interpreter, but not standalone
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    <p>Good morning! Recently I bought an Arduino board to make sort of "light control" in my room. Here is the code of the firmware I wrote:</p> <pre><code>int control = 0; int pin = 0; void setup() { Serial.begin(9600); for(pin = 0; pin &lt;= 13; pin++) pinMode(pin, OUTPUT); } void loop() { control = Serial.read(); if (control &gt; 0 &amp;&amp; control &lt;= 13) digitalWrite(control, HIGH); if (control &lt; 256 &amp;&amp; control &gt;= (256-13)) digitalWrite((256-control), LOW); } </code></pre> <p>After that, I used pySerial from Python interpreter to control the pins, and everything was working fine. Here is a piece of interpreter output:</p> <pre><code>Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) [GCC 4.4.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. &gt;&gt;&gt; import serial &gt;&gt;&gt; ser = serial.Serial('/dev/ttyUSB0', 9600) &gt;&gt;&gt; ser.write(chr(12)) &gt;&gt;&gt; # The light turned on here ... &gt;&gt;&gt; ser.write(chr(256-12)) &gt;&gt;&gt; # The light turned off here ... </code></pre> <p>Then I decided to write a simple Python script to do the same:</p> <pre><code>#!/usr/bin/env python import serial import time ser = serial.Serial('/dev/ttyUSB0', 9600) ser.write(chr(12)) time.sleep(1) ser.write(chr(256-12)) </code></pre> <p>But it doesn't work at all! The Arduino shows that something was received during the time I launched the script, but nothing happens. Here is a piece of strace output for the script:</p> <pre><code>open("/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NONBLOCK) = 3 ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(3, SNDCTL_TMR_START or TCSETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 open("/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NONBLOCK) = 4 ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(4, SNDCTL_TMR_START or TCSETS, {B9600 -opost -isig -icanon -echo ...}) = 0 ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, {B9600 -opost -isig -icanon -echo ...}) = 0 write(4, "\f", 1) = 1 close(4) = 0 rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER, 0x7f45cf4c88f0}, {0x4d9820, [], SA_RESTORER, 0x7f45cf4c88f0}, 8) = 0 exit_group(0) = ? </code></pre> <p>It looks like everything should be fine, so I don't know what the problem can be. I would appreciate any help, many thanks in advance!</p> <p>PS When I run the program under PDB, everything works fine. A Heisenbug.</p> <p>UPDATE: I made the controller send me back the data it was receiving and it looks like it isn't receiving anything when I am running the script, but receives everything when I send the data from the interpreter. The code of the firmware now looks like this:</p> <pre><code>int control = 0; int pin = 0; void setup() { Serial.begin(9600); for(pin = 0; pin &lt;= 13; pin++) pinMode(pin, OUTPUT); } void loop() { if (Serial.available() &gt; 0) { control = Serial.read(); if (control &lt;= 13) digitalWrite(control, HIGH); if (control &lt; 256 &amp;&amp; control &gt;= (256-13)) digitalWrite((256-control), LOW); Serial.println(control); } } </code></pre>
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    1. CODid `ser.write(chr(12)); time.sleep(1); ser.write(chr(256-12))` works fine from console?
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      1. POpySerial works fine in Python interpreter, but not standalone
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    2. COYes. Lights turn on, off, jpnevulator shows the data returned by controller. When I do the same from a script, jpnevulator shows no data returned and nothing happens.
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      1. POpySerial works fine in Python interpreter, but not standalone
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    3. COI upgraded pySerial, but no results.
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      1. POpySerial works fine in Python interpreter, but not standalone
      1. USIvan Galinskiy
 

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