Raspberry Pi Forums

knute

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.

knute

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.

knute

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...

knute

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...

knute

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

Thanks!

knute

Can you make the background opaque on your app?

knute

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.

knute

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...

knute

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...

knute

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'...

knute

And this simple intercom program written in Java for the Pi at http://pi.knutejohnson.com.

knute

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).

knute

Well it would be easy enough to modify that program to display 4 images and then you wouldn't have to go get them.

knute

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...

knute

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?

knute

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...

knute

Pardon my ignorance but how does one get this software? I would like to try it out.

knute

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...

knute

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 ...

knute

You can install openjdk8 and openjfx on the current raspbian and it will work fine.

knute

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...

knute

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...

knute

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

.

knute

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 ...

knute

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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