Device::Velleman::K8055

A Raku interface to the Velleman USB Experiment Kit.

Synopsis

use Device::Velleman::K8055;

my $device = Device::Velleman::K8055.new(address => 0);

react {
    whenever Supply.interval(0.5) -> $i {
        if $i %% 2 {
            $device.set-all-digital(0b10101010);
        }
        else {
            $device.set-all-digital(0b01010101);
        }
    }
    whenever signal(SIGINT) {
        $device.close(:reset);
        exit;
    }
}

See also the examples directory in the distribution.

Description

The Velleman K8055 is an inexpensive PIC based board that allows you to control 8 digital and 2 analogue outputs and read five digital and 2 analog inputs via USB. There are LEDs on the outputs that show the state of the outputs (which is largely how I've tested this.)

I guess it would be useful for experimenting or prototyping but it's rather big (about three times as large as a Raspberry Pi) so you may be rather constrained if you want to use it in a project.

This module has a fairly simple interface - I guess that a higher level abstraction could be provided but I only made it as an experiment and am not quite sure what interface would be best yet.

I've used the k8055 library by Jakob Odersky to do the low-level parts rather than binding libusb directly, but all the information is there is someone else wants to do that.

Install

You will need the development package of libusb in order to build this, this should be available through your system's package manager as libusb-devel or libusb-dev (if you are running a Linux.) At minimum it will require the 'usb.h' and the required library to link to in places where the C compiler can find them.

On a system that uses udev (most probably Linux,) you will need to make some configuration changes in order to be able to use it as a non-privileged user. You will need to perform these changes with root privileges.

Firstly copy the k8055.rules file to the udev rules directory (/etc/udev/rules.d on a typical installation,)

cp config/k8055.rules /etc/udev/rules.d

Then create a new group called k8055:

groupadd -r k8055

Finally add yourself (or other users that require access to the device,) to the new group:

usermod -a -G k8055 $(USER)

Where $(USER) is the user name of the user that want access. The access changes won't be available until the device is next plugged in and the user logs in again.

If the above steps haven't been done before trying to install the module, it will attempt to skip most of the tests and may even succeed in installing but may not work well.

If you have a working Rakudo installation you should be able to install with zef :

zef install Device::Velleman::K8055

Other installers may be available in the future.

Support

This is largely experimental and might prove fiddly to install so I won't be entirely surprised if you have problems with it, if however you have any suggestions, feedback or improvements than please post them on Github or even better send a pull request.

Copyright & Licence

This is free software, see the LICENCE file in the distrubution.

© Jonathan Stowe 2016 - 2019

The terms of the k8055 library used are described in its README.