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by knute
Sat Jan 19, 2019 3:10 am
Forum: Java
Topic: Desktop indicators bleed through JavaFX
Replies: 19
Views: 5657

Re: Desktop indicators bleed through JavaFX

You might give OpenJFX a try, it's in the repository. Tomorrow when I'm back in front of my Pi I'll post the code for a simple app and a screen shot. That may explain what's up.
by knute
Sat Jan 19, 2019 3:05 am
Forum: Advanced users
Topic: Virtual com port drivers?
Replies: 9
Views: 1758

Re: Virtual com port drivers?

So the /dev entries are created when the device is plugged in? That assumes a smart device yes, that tells the Pi what it is? Sorry to be so dense but this isn't something I have any familiarity with.
by knute
Fri Jan 18, 2019 8:55 pm
Forum: Java
Topic: Desktop indicators bleed through JavaFX
Replies: 19
Views: 5657

Re: Desktop indicators bleed through JavaFX

Maybe I should ask what Java and JavaFX you are using? And what version of Raspbian? I know that some early versions would only run through the framebuffer. I've run a few JavaFX programs under OpenJDK and OpenJFX and they window just like a Swing app does. Can you post your code or is it super secr...
by knute
Fri Jan 18, 2019 8:50 pm
Forum: Advanced users
Topic: Virtual com port drivers?
Replies: 9
Views: 1758

Re: Virtual com port drivers?

COM ports are a windows construct. USB-serial devices appear as tty's (terminal devices) as /dev/ttyUSB0 - /dev/ttyUSBx. You can access them through various file stream utilities (i.e. echo "blah" > /dev/ttyUSB0 results in blah being transmitted on the wire) or via system calls in your own programs...
by knute
Thu Jan 17, 2019 9:50 pm
Forum: Advanced users
Topic: Virtual com port drivers?
Replies: 9
Views: 1758

Virtual com port drivers?

Are there virtual com port drivers for serial to USB devices?

Thanks!
by knute
Thu Jan 17, 2019 9:47 pm
Forum: Java
Topic: Desktop indicators bleed through JavaFX
Replies: 19
Views: 5657

Re: Desktop indicators bleed through JavaFX

Can you make the background opaque on your app?
by knute
Thu Jan 17, 2019 4:04 am
Forum: Beginners
Topic: UART on Pi3B & 3B+ ?
Replies: 5
Views: 836

Re: UART on Pi3B & 3B+ ?

klricks wrote:
Wed Jan 16, 2019 4:24 am
knute wrote:
Wed Jan 16, 2019 3:53 am
.....The second is, is there any hardware flow control available (RTS,CTS)?
If UART 1 is used then RTS and CTS is available.

(UART 0 has no flow control)
Is there documentation somewhere on which pins for RTS/CTS and on the port in general?

Thanks.
by knute
Thu Jan 17, 2019 4:02 am
Forum: Beginners
Topic: UART on Pi3B & 3B+ ?
Replies: 5
Views: 836

Re: UART on Pi3B & 3B+ ?

I ran a RPi to Arduino Due serial communication at 230400 without issues. I did not use any hardware flow control. I used software flow control. I used "<" to start a message and ">" to end a message sentence for each direction. I'd ignore bytes till the data stream hit a ">" and keep collecting da...
by knute
Wed Jan 16, 2019 3:53 am
Forum: Beginners
Topic: UART on Pi3B & 3B+ ?
Replies: 5
Views: 836

UART on Pi3B & 3B+ ?

I've got a project coming that needs to communicate via serial and I have no experience with Pis and the serial port. Fortunately it is 3.3v and won't require any level conversion. My first question is about baud rates and buffers. Can the Pi receive data at 115200 baud and clear the buffer fast eno...
by knute
Wed Jan 09, 2019 3:59 pm
Forum: Networking and servers
Topic: Setting up "basic" mail
Replies: 5
Views: 1663

Re: Setting up "basic" mail

mail is part of the mailutils package (and I think some other). It delivers mail to a user or to a mail transfer agent. You need to install the rest of the mail system however, something to collect and deliver the mail. I really like sendmail for that but you will get plenty of other suggestions. I'...
by knute
Tue Jan 08, 2019 2:25 am
Forum: Graphics, sound and multimedia
Topic: Raspberry Pi two way communication
Replies: 2
Views: 2141

Re: Raspberry Pi two way communication

And this simple intercom program written in Java for the Pi at http://pi.knutejohnson.com.
by knute
Sun Jan 06, 2019 8:20 pm
Forum: Beginners
Topic: how install openjdk?
Replies: 8
Views: 15492

Re: how install openjdk?

I got around that by uninstalling the installed Java first. Then install openjdk. I'm not sure but I think it is a problem with the installer looking in the wrong place for certificates (but I could definitely be wrong).
by knute
Sun Dec 30, 2018 10:59 pm
Forum: Python
Topic: Automatic opening of a picture
Replies: 6
Views: 908

Re: Automatic opening of a picture

Well it would be easy enough to modify that program to display 4 images and then you wouldn't have to go get them.
by knute
Sun Dec 30, 2018 3:27 am
Forum: Python
Topic: Automatic opening of a picture
Replies: 6
Views: 908

Re: Automatic opening of a picture

I'm not much of a Python programmer but in Java reading an image file and displaying it is fairly easy. Every 10 seconds this program reads the file Desktop\image.jpg and displays it scaled and centered in a frame. If you resize the frame the image will resize. Just copy your dated file to another f...
by knute
Mon Dec 24, 2018 10:00 pm
Forum: General discussion
Topic: Create scrolling news ticker nu.nl
Replies: 2
Views: 383

Re: Create scrolling news ticker nu.nl

I've programmed news tickers before in Java but on faster computers with much faster video. I'm not sure that a Pi has quite enough oomph to display a ticker. How fast do you need it to tick?
by knute
Thu Dec 13, 2018 4:29 pm
Forum: Camera board
Topic: Raspixxx camera software - changes
Replies: 6
Views: 898

Re: Raspixxx camera software - changes

Pardon my ignorance but how does one get this software? I would like to try it out. As @JamesH mentions above: it's not in the regular repo, so you have to get the source from the 'userland' git repository and then build it. The repo is at https://github.com/raspberrypi/userland (use 'git clone' or...
by knute
Thu Dec 13, 2018 3:39 pm
Forum: Camera board
Topic: Raspixxx camera software - changes
Replies: 6
Views: 898

Re: Raspixxx camera software - changes

Pardon my ignorance but how does one get this software? I would like to try it out.
by knute
Wed Dec 12, 2018 2:09 am
Forum: Troubleshooting
Topic: SOLVED:pigpio problem with the latest raspbian
Replies: 0
Views: 210

SOLVED:pigpio problem with the latest raspbian

I installed the latest version of raspian lite and configured it. I then downloaded pigpio and tried to use a simple C program that reads a DHT sensor and got the following error message: 2018-12-11 20:07:12 initMboxBlock: init mbox zaps failed I get the same message if I attempt to start pigpiod. I...
by knute
Mon Dec 03, 2018 10:21 pm
Forum: Java
Topic: Raspbian Stretch Lite - simple Oracle JRE installation
Replies: 5
Views: 10572

Re: Raspbian Stretch Lite - simple Oracle JRE installation

Hello, What is the simplest way to install Java JRE? I don't need JDK. Just install OpenJDK. I just want two things: - I want to receive updates with apt-get upgrade So install OpenJDK. - I want fast JRE - so probably Oracle instead of Open JRE OpenJDK is the same code as Oracle now and it is just ...
by knute
Thu Nov 15, 2018 12:16 am
Forum: Java
Topic: Raspbian that supports javafx
Replies: 1
Views: 3640

Re: Raspbian that supports javafx

You can install openjdk8 and openjfx on the current raspbian and it will work fine.
by knute
Sun Nov 11, 2018 4:09 pm
Forum: Java
Topic: Java future on ARM
Replies: 21
Views: 7891

Re: Java future on ARM

I found a testing build of jdk-11 for arm on Aleksey Shipilev's site, https://shipilev.net/. The jdk-11 for arm builds are at https://builds.shipilev.net/openjdk-jdk11/. I tried it on my Pi3+ and it seems to work fine. You can get openjfx11 early access at https://gluonhq.com/products/javafx/. I tri...
by knute
Sat Nov 10, 2018 10:15 pm
Forum: Java
Topic: Java future on ARM
Replies: 21
Views: 7891

Re: Java future on ARM

openjdk-9 is available in the stretch repository now. I don't think 10 is going to give you anything substantial over 9. 11 is the long term support version. I would hope that 11 is incorporated into buster but who knows. I'm running openjdk-8 which is version 1.8.0_181 on one machine. I haven't not...
by knute
Thu Sep 13, 2018 4:02 am
Forum: Other projects
Topic: Restaurant Order Number/Now Serving
Replies: 3
Views: 712

Re: Restaurant Order Number/Now Serving

Another thing you could do is use a monitor with speakers facing the customers and announce the new number when it is posted. I don't know if there is any to speech software that runs on a Pi. You could always record a hundred numbers and play the file :-).
by knute
Wed Sep 12, 2018 4:00 am
Forum: Raspbian
Topic: How to use dtoverlay=dht11
Replies: 3
Views: 657

Re: How to use dtoverlay=dht11

There seems to be support for DHT11/DHT21/DHT22 humidity/temperature sensors - but I can find no examples of how to use this. This appears to create a character mode device /dev/iio:device0 I have a DHT11 attached to GPIO4 which works with other software, but /dev/iio:device0 does not appear to do ...
by knute
Wed Sep 12, 2018 3:35 am
Forum: Other projects
Topic: Restaurant Order Number/Now Serving
Replies: 3
Views: 712

Re: Restaurant Order Number/Now Serving

Sounds like a fun project. You didn't specify how far the kitchen and dining room were apart or where the numeric keypad would be in relation to either. There are some limits on how far HDMI cables can be run, same with USB cables. If you bought an HDMI splitter and put it with the Pi between the ki...

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