Op 24-07-16 om 16:29 schreef James Richters:
Bo,
I also have a raspberry pi project.. I got a hifi-berry card for it and it
is streaming audio to a central audio system, I'm using VLC media player and
an app on my cell phone to control it, I have not made use of the GPIO on
them yet, but I would really like to learn how this can be accomplished with
FPC, since I am more familiar with pascal than any other language, it would
be great to learn how to do this! I have a particular application in mind.
I have a relay board that will turn relays on and off with TTL level
signals, what I wish to do is have a remote way to turn certain amplifiers
on and off. There are 24 amplifiers going to 44 speakers (4 are
subwoffers) in and around my house, sometimes I'll want just downstairs and
outside amps on, other times I'll want just one room on, or all amps on....
etc. The amps are all in my crawlspace under the first floor, and that's
where the raspberry pi is. I also have some volume control chips that are
controlled by clocking data into them, I could chain them all together and
be able to control all of them with just one clock and one data bit.
Any advice on how to get started on controlling GPIO with a raspberry pi
with FPC would be greatly appreciated!
-----Original Message-----
From: fpc-pascal-boun...@lists.freepascal.org
[mailto:fpc-pascal-boun...@lists.freepascal.org] On Behalf Of Bo Berglund
Sent: Sunday, July 24, 2016 2:22 AM
To: fpc-pascal@lists.freepascal.org
Subject: Re: [fpc-pascal] Parallel Port Access with Free Pascal - windows
On Fri, 22 Jul 2016 14:19:20 +0000, Mark Morgan Lloyd
<markmll.fpc-pas...@telemetry.co.uk> wrote:
Or go the whole hog and
port the program onto a Raspberry Pi: Bo's doing something like you're
asking.
Yes, indeed! I now have something like 7-8 operational RPi units for
different purposes and in several places I have used the GPIO pins to
control and read back digital stuff from FPC programs. Very convenient.
Last I did was to attach a 4-way relay board to a RPi and put a smapp FPC
command line program on it, which gets called from a PHP script on the
Apache webserver on the Pi.
Now I have a webpage, with which I can switch on/off the relays with in
order to control the operational state of some measuring equipment sitting
half way across the workd!
You could do a LOT with FPC and a Raspberry Pi!
Examples:
The Pi also runs an OpenVPN server so I can access it with PuTTY and/or
TightVNC to program it if I need to.
My Pi also has a port mapping utility which makes it possible for me to
remotely access a WiFi network device on a WiFi access point close to the
RPi again from a long distance away. THis was created with FPC and Indy10 on
the RPi.
While Bo's contribution is valid, I have the impression that the
raspberry is going to the pigpiod. Newer raspbian images have a switch
(in raspi-config/advanced options) to enable a gpio-server. Using that
it is possible to access all gpio-functions (gpio, serial, spi, pwm,
...) as a normal user. See http://abyz.co.uk/rpi/pigpio/index.html.
There is a snag : the communication with the server happens via the
network, so it could be that your pi will be hijacked, unless you take
precautions.
FWIW, I ported the library to fpc, together with the test/demo software
(x_pigpiod_if2).
The fact that the communication goes via the network opens possibilities
though. I tested my port on my laptop, connected to the pi. So
applications running on a remote PC could control the pi's IO.
I have no public place to publish this software, so if anyone is
interested, please ask.
Koenraad.
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