HAL (Heuristically programmed ALgorithmic computer) is a sentient computer (or artificial intelligence) that controls the systems of the UrLab spacecraft and interacts with the Hackerspace crew.
HAL is made of 3 main components. An arduino library implementing access to various actuators and sensors, mainloop and serial communication. A Linux (probably also *BSD/Mac) driver to access the sensors and actuators with any user on the filesystem. Finally, a Python hilevel API to wrap all the boilerplate filesystem access code.
In order to build your own HAL, you need at least the arduino library and an arduino sketch that use it, and the driver.
- hal-arduino is the arduino library
- hal-driver is a FUSE (FileSystem in USerspace) driver to expose arduino sensors and actuators on the filesystem
- halpy is a high level python API
This repo package all this components together, along with the arduino sketch and scripts that are specific to UrLab.
In order to use this particular repo:
$ git submodule init && git submodule update
$ sudo apt-get install arduino-core libfuse-dev
$ virtualenv --distribute --no-site-packages ve
$ source ve/bin/activate
$ pip install -r requirements.txt
$ pushd halpy && python setup.py develop && popd
$ make
$ mkdir halfs
$ driver/driver halfs
Suppose we have an arduino, and we connected a ledstrip (its luminosity can vary over time); a light sensor (a photoresistor), a relay to control whether an audio amplifier is powered or not, and a button. Using the command tree, we obtain the following filesystem:
$ tree -p /hal/
/hal/
├── [dr-xr-xr-x] animations
│ └── [dr-xr-xr-x] ledstrip
│ ├── [-rw-rw-rw-] fps
│ ├── [--w--w--w-] frames
│ ├── [-rw-rw-rw-] loop
│ └── [-rw-rw-rw-] play
├── [dr-xr-xr-x] driver
│ ├── [-rw-rw-rw-] loglevel
│ ├── [-r--r--r--] rx_bytes
│ ├── [-r--r--r--] tx_bytes
│ ├── [-r--r--r--] uptime
│ └── [-r--r--r--] version
├── [lr--r--r--] events -> /tmp/hal.sock
├── [dr-xr-xr-x] sensors
│ └── [-r--r--r--] light
├── [dr-xr-xr-x] switchs
│ └── [-rw-rw-rw-] amplifier_relay
├── [dr-xr-xr-x] triggers
│ └── [-r--r--r--] button
└── [-r--r--r--] version
In the script directory:
from config import get_hal
from halpy.generators import Partition, Note, Silence
hal = get_hal()
hal.sensor('temp_ambiant')
hal.stop('buzzer')
hal.fps('buzzer', 17)
hal.one_shot('buzzer')
hal.upload('buzzer', Partition(Note(440), Silence(), Note(494)).to_frames())
hal.play('buzzer')Switchs are binary outputs (on/off). Just write 1 or 0 to halfs/switchs/<name>
to put it on or off. You may also retrieve its actual status by reading the file.
Animations are sequences of bytes (0, 1, ... , 254, 255), usually played on ledstrips or a buzzer. You can:
- Upload an animation by writing between 1 and 255 bytes to
halfs/animations/<name>/frames - Set its speed by writing a number between 4 and 1000 to
halfs/animations/<name>/fps - Control if it should play one time or loop continuously by writing 0 or 1 to
halfs/animations/<name>/loop - Start or stop it by writing 0 or 1 to
halfs/animations/<name>/play
You may also get the fps, playing status and loop status by reading corresponding files.
Sensors are analog sensors, varying between 0 and 1 (1024 different values as float).
Just read halfs/sensors/<name> to get value
Triggers are binary sensors. Just read halfs/triggers/<name> to get value.
You may be also interested in trigger state change in real time, without
continuously reading the file. You can read the UNIX socket in halfs/events,
which outputs a line every time a trigger state changes. This line has the
following format: <sensor_name>:<status>, for example bell:1 or knife:0.
- HAL-Arduino should return its actual Git version; not an arbitrary string
- More security check (bound checking, syscall return values, ...)