CompuCanvas code

command line control

The peripheral devices incorporated into CompuCanvas systems have been selected (among other factors) because they can be controlled in a straightforward way from the command line on an rPi. Below are command line examples for each device.

CircuitPython devices

CircuitPython devices from AdaFruit (running the 2.0.0 firmware), like the Trinket M0, Gemma M0 and Circuit Playground Express offer 2 distinct modes of command line control. First, the device mounts as a USB drive at /media/pi/CIRCUITPY (additional devices at CIRCUITPY1, CIRCUITPY2, etc.). This directory contains a main.py Python file which is run every time the device resets. Editing and saving main.py will force a reset and then run the new version.

The CircuitPython device also appears at /dev/ttyACM0 (or ACM1, ACM2, etc). Run the command screen /dev/ttyACM0 and then press Ctrl-c and Enter once or twice and you should see a >>> Python REPL prompt. Typing the commands below should display information about the device:

import os
os.uname()

Pressing Ctrl-d in the REPL will cause the device to reset and run the main.py file again. If there is a bug in main.py, error details (including line numbers) will be displayed in the REPL after a Ctrl-d reset. To exit the screen command and return back to the Linux command line prompt, type Ctrl-a, k, y.

Pimoroni Blinkt

The Pimoroni Blinkt device has 8 RGB LEDs which can be controlled via Python (either REPL or scripts). Note that the Blinkt is not configured as part of the sudo-setup.sh script discussed below. Setup and usage of the Blinkt is described here, but the initial one-time setup is a single line command:

curl https://get.pimoroni.com/blinkt | bash

Reboot is recommended after the setup script is run. To test the Blinkt, try Python like this:

import time
from blinkt import set_pixel, set_brightness, show, clear
set_brightness(0.3)
clear()
set_pixel(0,   0,   0, 100)
set_pixel(1,   0, 100, 0)
set_pixel(2, 100,   0, 0)
set_pixel(3,   0, 100, 100)
set_pixel(4, 100, 100, 0)
set_pixel(5, 100,   0, 100)
set_pixel(6, 100, 100, 100)
set_pixel(7,  10,  10, 10)
show()
while True:
  time.sleep(1.0)

BlinkStick

Use the blinkstick command to control BlinkStick lights. Run blinkstick --help to see usage information. Here are some example commands:

blinkstick --pulse red
blinkstick --index 0 --pulse red
blinkstick --index 1 --limit 40 green

text to speech

Use the espeak command to make the CompuCanvas talk. Note that this command emits some spurious errors which can be directed to /dev/null like this:

espeak "Hello" 2>/dev/null

Run espeak --help to see usage information.

playing MP3s

The mpg321 program has been installed for playing audio files. Run mpg321 --help for usage information. Given an audio file named song.mp3, play it with:

mpg321 song.mp3

Show2 with Weatherboard

For CompuCanvas systems that incorporate the ODROID Show2 with WeatherBoard, see the Show2-Eboogaloo repo. When the Show2 is placed behind the canvas, the text needs to be big to be readable. It also helps to turn up the LCD backlight intensity. For example:

cd ~/Show2-Eboogaloo
./show2.sh siz7 blt255 fg2 /0/Hello fg3 /1/World

Maxbotix Ultrasonic Rangefinder

For CompuCanvas systems that incorporate a USB connected Maxbotix Ultrasonic Rangefinder (like from Adafruit), try this to see the raw range data:

( stty -F /dev/ttyUSB0 57600 ; cat /dev/ttyUSB0 )

CompuCanvas Controller

The CompuCanvas Controller (C3) is a work in progress based on headless Eclipse 4.5 and Java 8 (included in Raspbian distribution). Normally it will be started on bootup (see /etc/rc.local and the sudo-setup.sh script discussed below) and will monitor sensors, blink lights, play sounds and otherwise do 'interesting things' in a hopefully unobtrusive and non-annoying manner. To check out C3:

cd ~/CompuCanvas-code/CompuCanvas-controller/C3-runtime
./c3.sh status

Invoking c3.sh with no arguments will show a usage message which, in addition to status describes start and stop arguments. Check out the c3.log file for details on C3 operation.

new system configuration

First, burn Raspbian image onto a microSD; enable ssh login by creating an empty file named ssh at the top-level; boot and login (user:pi ; pw:raspberry); then run the following command to set a new password:

sudo passwd pi

Next, run sudo raspi-config and:

in Localization Options, set Timezone
in Advanced Options, set Memory Split to 16 for GPU
tweak other settings as desired, then reboot!

Finally, clone the CompuCanvas code and run the system setup script:

git clone https://github.com/cjdaly/CompuCanvas-code.git
cd CompuCanvas-code/CompuCanvas-scripts/setup
sudo ./sudo-setup.sh
sudo reboot

When this reboot completes you should hear "Hello from CompuCanvas..." and see the BlinkStick lights in operation.

cjdaly / CompuCanvas-code

readme