A python script to read analog values on the Intel Galileo
The Intel Galileo is a great device for tinkering with the IoT. After tinkering with it for a bit I was unable to find a working example of reading an analog sensor with the linux side of the Galileo.
This imports the MRAA library and converts the reading to volts. As a sanity check it also reads the files in /sys/bus/iio/devices/iio:device0/in_voltage
usage: analog.py [-h] [--temperature] [--count COUNT] [--version] pinNumber
Analog Pin Value Reader for Galileo
positional arguments:
pinNumber Specify the analog pin number, i.e. 0-5
optional arguments:
-h, --help show this help message and exit
--temperature Print a temperature value for TMP36
--count COUNT Number of times to execute, default infinity
--delay DELAY Number of seconds to wait between readings, default 10
--quiet Quiet display, show only the voltage of the analog pin
--version show program's version number and exit
This example shows reading an analog sensor (TMP36) on A0.
root@galileo:~# ./analog.py 0
+---------------------------+---------------------+
| Data Type | Value |
+---------------------------+---------------------+
| Raw MRAA Reading | 568 |
| MRAA Voltage Calc | 0.694 |
| sys/bus/iio Raw Reading | 580 |
| /sys/bus/iio scale | 1.2207 |
| sys/bus/iio Voltage Calc | 0.708 |
| Time | 2015/12/21 06:38:18 |
+---------------------------+---------------------+
If you have a TMP36 temperature sensor you can pass --temperature in on the command line to display the calculated temperature.
root@galileo:~# ./analog.py 1 --temperature
+---------------------------+---------------------+
| Data Type | Value |
+---------------------------+---------------------+
| Raw MRAA Reading | 568 |
| MRAA Voltage Calc | 0.694 |
| sys/bus/iio Raw Reading | 568 |
| /sys/bus/iio scale | 1.2207 |
| sys/bus/iio Voltage Calc | 0.693 |
| Celsius | 19.35 |
| Fahrenheit | 66.84 |
| Time | 2016/01/05 04:42:11 |
+---------------------------+---------------------+
To run it 5 times on A0 with a delay of 1 second and show the temperature.
root@galileo2:~# ./analog.py 0 --count 5 --delay 1 --temperature
Pull up resister set to hi, attempting to change.
+---------------------------+---------------------+
| Data Type | Value |
+---------------------------+---------------------+
| Raw MRAA Reading | 568 |
| MRAA Voltage Calc | 0.694 |
| sys/bus/iio Raw Reading | 580 |
| /sys/bus/iio scale | 1.2207 |
| sys/bus/iio Voltage Calc | 0.708 |
| Celsius | 19.35 |
| Fahrenheit | 66.84 |
| Time | 2016/01/05 04:47:31 |
+---------------------------+---------------------+
To only display the voltage of A1 and exit.
root@galileo2:~# ./analog.py 1 --quiet --count=1
0.694
There is a prerequisite of installing the module PrettyTable. If you have not installed PIP, follow these instructions.
curl https://bootstrap.pypa.io/ez_setup.py -o ez_seetup.py
python ez_setup.py --insecure
Then you must install PIP.
curl https://pypi.python.org/packages/source/p/pip/pip-8.0.2.tar.gz -o pip-8.0.2.tar.gz
tar -zxvf pip-8.0.2.tar.gz
cd pip-8.0.2
python setup.py build install
Install PrettyTable
pip install PrettyTable
Download the script and make it executable.
curl https://raw.githubusercontent.com/joemcmanus/analog/master/analog.py -o analog.py
chmod 755 analog.py
Wiring the TMP36
