Arduino controller

This set of program allows one to order easily from a perl script an Arduino to switch on or off output pins which may be connected to a relay card and retrieve temperature from DS18B20 temperature sensors.

Find out more info (in french) at my homepage

Relay card

The Arduino is connected to the relay card with the power supply and output pins. It can be used to switch on of off a lamp.

Temperature

The sketch is also able to handle thermal sensors DS18B20 connected to pin number 10.

Software

A perl script communicate through the emulated serial port with the Arduino with a simple exchange protocol to retrieve state and temperature and swith on or off ouputs. The Arduino listens for order and executes them.

Arduino

Just load the sketch with the Arduino IDE and upload it. Next, connect directly to the Arduino with a serial console. On linux, just use picocom :

picocom /dev/ttyACM0 -b 9600

Welcome message

Like a shell, a prompt listen for inputs. To display the help, just type h.

> h
    ___          _       _
   / _ \        | |     (_)
  / /_\ \_ __ __| |_   _ _ _ __   ___
  |  _  | '__/ _` | | | | | '_ \ / _ \
  | | | | | | (_| | |_| | | | | | (_) |
  \_| |_/_|  \__,_|\__,_|_|_| |_|\___/

  Build Feb  7 2015 : 14:10:41

Help
Command available :
      <pin number [2-9]>=<0,1>
      h - help
      s - i/o status
      t - temperature

Output controller

To display the state of outputs, type s

> s
I/O Status :
  2 => 0
  3 => 0
  4 => 0
  5 => 0
  6 => 0 (R)
  7 => 0 (R)
  8 => 0 (R)
  9 => 0 (R)

The output 2 to 9 are listed and they are all in low (0) state. For my needs, outputs connected to relay are inverted. The are identified with the (R) symbol.

In order to switch an output on or off, the command is composed from the output number followed by the sign = and with 1 (high) or 0 (low). eg : switch on the output n°2 :

> 2=1
  OK

Check the state :

> s
I/O Status :
  2 => 1
  3 => 0
  4 => 0
  5 => 0
  6 => 0 (R)
  7 => 0 (R)
  8 => 0 (R)
  9 => 0 (R)

To setup pins output for relay, you'll need to edit sketch.ino to change the array accordingly.

• 0 is normal output
• 1 is for inverted output

// pin 6 - 9 are connected to relay
const int relays[NB_OUTPUT] = {0,0,0,0,0,0,1,1,1,1};

Temperature

In order to display the temperature, type t. The program look for any thermal sensors DS18B20 connected to it, for each found, it request the temperature and displays it in Celsius.

> t
Temperature :
ROM = [ 28 A 4C 3B 4 0 0 5B ] - Temperature : 12.69 °C
ROM = [ 28 6 AD 33 4 0 0 2D ] - Temperature : 15.94 °C

Perl

The perl script handles the communication described above and offer a cli usage.

Thoses scripts requires the following perl lib : libdevice-serialport-perl and libconfig-simple-perl.

Outputs controller

It handles the communication with the Arduino with the protocol stated before, displays and change the state of the desired output.

Usage :

> ./pin.pl
./pin.pl [-p dev] (<pin> <state> | status)
        <dev>   - device [/dev/ttyACM0]
        status  - retrieve the current status of the outputs
        <pin>   - pin number
        <action> - low|off / high|on / toggle

Display the state of output, like above :

> ./pin.pl status
Status
  2 => 1
  3 => 0
  4 => 0
  5 => 0
  6 => 0 (R)
  7 => 0 (R)
  8 => 0 (R)
  9 => 0 (R)

Swith on the output number 2

> ./pin.pl 2 on

toggle an output

> ./pin.pl 2 toggle

Temperature

This script retrieves the temperature of all DS18B20 sensors connected to the Arduino and logs it in a file named temperature.<date>.log in the folder /var/lib/temperature/. One line per invocation at the end of the file. The date is formatted as %Y-%m-%d. It also reads a configuration file /etc/arduino.cfg in order to provide a name for the 64 bit adresses of thermal sensors. The file looks like this :

sensor1=28 A 4C 3B 4 0 0 5B : ext. nord
sensor2=28 6 AD 33 4 0 0 2D : garage

and when the line added to the file is :

2015-10-13 00:00:05 : ext. nord=11.13 - garage=14.88 -

Usage :

> ./temperature.pl
./temperature.pl usage:
        -d : debug output