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by knute
Sun Aug 04, 2019 5:22 pm
Forum: Troubleshooting
Topic: crontab update
Replies: 16
Views: 1454

Re: crontab update

Yes I know via crontab -e and then 0 16 * * * sudo apt-get update && sudo apt-get upgrade, && sudo reboot but it doesn't work If apt-get upgrade stops and asks for input it isn't going to get any and will hang right there forever. One of the easiest ways to know that cron has done a job for you is ...
by knute
Sat Aug 03, 2019 8:04 pm
Forum: Java
Topic: Install Java7 on Raspian buster
Replies: 10
Views: 3976

Re: Install Java7 on Raspian buster

tomcat 8 and 9 are available for Buster. Java 11 is the standard on Buster. Can you not run tomcat with Java 11? Java 8, 9, and 10 are also available for Buster.
by knute
Sat Aug 03, 2019 7:57 pm
Forum: Java
Topic: If else help
Replies: 16
Views: 4714

Re: If else help

Download the docs, they are very helpful. An show us your code! java.lang.String boolean equalsIgnoreCase​(String anotherString) Compares this String to another String, ignoring case considerations. String toLowerCase() Converts all of the characters in this String to lower case using the rules of t...
by knute
Thu Aug 01, 2019 5:09 pm
Forum: Beginners
Topic: Restarting after a shut down w/o pulling the power cord?
Replies: 5
Views: 311

Re: Restarting after a shut down w/o pulling the power cord?

Momentarily ground GPIO pin BCM 3.
by knute
Sun Jul 28, 2019 7:34 pm
Forum: Troubleshooting
Topic: Java code into android app
Replies: 4
Views: 213

Re: Java code into android app

Take a look at this. I haven't had time to try it but I think it is exactly what you are looking for.

https://gluonhq.com/products/mobile/javafxports/
by knute
Sat Jul 27, 2019 9:13 pm
Forum: Beginners
Topic: Microphone audio input to hdmi output
Replies: 7
Views: 349

Re: Microphone audio input to hdmi output

Well with usb microphones, I can only find either bulky expensive ones, or small ones like this: https://www.amazon.com/Tanbin-Computer-Microphone-Smallest-Recording/dp/B06XVMP7FF/ref=sr_1_5?keywords=small+usb+microphone&qid=1564154470&s=gateway&sr=8-5 I need it to be small, but these kinds ^^ seem...
by knute
Fri Jul 26, 2019 3:11 pm
Forum: Beginners
Topic: Microphone audio input to hdmi output
Replies: 7
Views: 349

Re: Microphone audio input to hdmi output

A simple USB microphone won't work?
by knute
Fri Jul 26, 2019 3:08 pm
Forum: Troubleshooting
Topic: pigpio?
Replies: 2
Views: 174

Re: pigpio?

Thanks Joan!
by knute
Thu Jul 25, 2019 10:08 pm
Forum: Troubleshooting
Topic: pigpio?
Replies: 2
Views: 174

pigpio?

Is it possible to run two programs using the pigpio libraries at the same time? I'm getting an error that leads me to think that isn't possible.

2019-07-25 17:05:21 initInitialise: Can't lock /var/run/pigpio.pid

Thanks!
by knute
Tue Jul 23, 2019 3:46 pm
Forum: Beginners
Topic: Raspberry Pi 3 Temperature sensor setup
Replies: 3
Views: 171

Re: Raspberry Pi 3 Temperature sensor setup

Go to my website and look at the first article: http://pi.585ranch.com/, it has a picture on how to wire the DHTxx parts. It also has a description of how to use the dtoverlay to get the temperature and humidity data from a DHTxx part and some simple programs to do that.
by knute
Mon Jul 22, 2019 11:24 pm
Forum: Advanced users
Topic: RaspberryPi 4: heatsink or fan
Replies: 84
Views: 40477

Re: RaspberryPi 4: heatsink or fan

I saw somebody post the other day about some small fans by Noctua so I bought a 5V version. It really keeps the temp down. Now with ambient temp 27C the Pi idles at about 40C. I ran it at 98% to 99% for 20 minutes and it was about 60C at the end. I have one of those little aluminum heat sinks on the...
by knute
Mon Jul 22, 2019 10:55 pm
Forum: Beginners
Topic: Raspberry Pi 3 Temperature sensor setup
Replies: 3
Views: 171

Re: Raspberry Pi 3 Temperature sensor setup

If you have a bare sensor you need a pull-up resister. 10k will work I'm pretty sure but the device spec is for 5.1k. If you have the sensor on a board then it already has the pull-up resistor. You don't need the board you can just connect the wires. Some heat shrink tubing is good to keep them from...
by knute
Fri Jul 19, 2019 7:02 pm
Forum: Java
Topic: If else help
Replies: 16
Views: 4714

Re: If else help

Use the Console class for console I/O. Simple example of what you said you wanted. import java.io.*; public class test { public static void main(String... args) { Console con = System.console(); if (con != null) { System.out.println("good console - enter a line of text"); String str = con.readLine()...
by knute
Wed Jul 17, 2019 8:34 pm
Forum: Java
Topic: JavaMail issue on Pi0 and 1 with openjdk-11
Replies: 3
Views: 3541

Re: JavaMail issue on Pi0 and 1 with openjdk-11

To me it seems like JVM cannot offer appropriate ... well... Certificate? Does not support protocol? Something like that. Maybe OpenJDK11 has That's kind of what I thought but I'm not so sure now. I looked at that link but didn't see anything that I thought was obvious. I did however find a simple ...
by knute
Wed Jul 17, 2019 4:03 pm
Forum: Java
Topic: JavaMail issue on Pi0 and 1 with openjdk-11
Replies: 3
Views: 3541

JavaMail issue on Pi0 and 1 with openjdk-11

I have found some sort of a problem with JavaMail and openjdk-11 on a Pi0 or 1. To run Java 11 on a Pi0 or 1 you have to include the -zero command line option since openjdk-11 java won't run on a Pi0 or 1. The fix is to install the package openjdk-11-jre-zero which will run on a Pi0 or 1. But I'm ha...
by knute
Wed Jul 17, 2019 3:53 pm
Forum: Java
Topic: java is not supported any more on Pi0 with OS buster
Replies: 8
Views: 7765

Re: java is not supported any more on Pi0 with OS buster

So there is an interesting fault when openjdk-11 is installed on a Pi0 or Pi1. The script that sets the ca-certificates doesn't run because it call java without the -zero option and fails. This causes it to fail doing some things that require use of the certificate (eg. java.mail). Today I'm going ...
by knute
Wed Jul 17, 2019 2:13 pm
Forum: Java
Topic: java is not supported any more on Pi0 with OS buster
Replies: 8
Views: 7765

Re: java is not supported any more on Pi0 with OS buster

So there is an interesting fault when openjdk-11 is installed on a Pi0 or Pi1. The script that sets the ca-certificates doesn't run because it call java without the -zero option and fails. This causes it to fail doing some things that require use of the certificate (eg. java.mail). Today I'm going t...
by knute
Fri Jun 28, 2019 10:22 pm
Forum: Raspbian
Topic: Suggestion: Reporting ip address in /boot/boot.ip
Replies: 37
Views: 1718

Re: Suggestion: Reporting ip address in /boot/boot.ip

I do a lot of development on a Windows 10 machine. I use it to burn my SD cards. I've installed Bonjour but for the life of me can't get it to find other computers on the network with their hostname. ... Can you find other computers by name from a Pi or other computers on the network? Newer updates...
by knute
Fri Jun 28, 2019 9:14 pm
Forum: Raspbian
Topic: Suggestion: Reporting ip address in /boot/boot.ip
Replies: 37
Views: 1718

Re: Suggestion: Reporting ip address in /boot/boot.ip

I do a lot of development on a Windows 10 machine. I use it to burn my SD cards. I've installed Bonjour but for the life of me can't get it to find other computers on the network with their hostname. What I think would be the slickest setup for people that have lots of Pis running headless using DHC...
by knute
Fri Jun 28, 2019 3:34 pm
Forum: Troubleshooting
Topic: Raspbian Buster Java8 error
Replies: 1
Views: 175

Re: Raspbian Buster Java8 error

I don't think there is any going back. What's the error?
by knute
Thu Jun 27, 2019 9:05 pm
Forum: Java
Topic: java is not supported any more on Pi0 with OS buster
Replies: 8
Views: 7765

Re: java is not supported any more on Pi0 with OS buster

Buster, openjdk-11-jdk, openjdk-11-jre-zero and the -zero command line option is all that's needed. It is really slow in a Zero though.
by knute
Sun Jun 16, 2019 4:24 pm
Forum: Automation, sensing and robotics
Topic: How do I take a monitor screen and have the Pi be able to "watch it"
Replies: 1
Views: 379

Re: How do I take a monitor screen and have the Pi be able to "watch it"

I know that you can capture an image of a portion of the screen with Java. I assume that other languages have methods to do that as well.
by knute
Sat Jun 15, 2019 5:52 pm
Forum: Java
Topic: Having Trouble Stopping Audio Capture with Java
Replies: 1
Views: 617

Re: Having Trouble Stopping Audio Capture with Java

You don't say what device the TargetDataLine is connected to. If connected to a device such as a microphone, drain() will never return because the mixer connected to the microphone will continue to send data to the TargetDataLine's buffer which drain() will attempt to empty but never succeed. Just c...
by knute
Thu Jun 13, 2019 8:56 pm
Forum: Java
Topic: JavaFX application not working on Raspbian Stretch/Raspberry Pi Zero W 1.1
Replies: 8
Views: 8276

Re: JavaFX application not working on Raspbian Stretch/Raspberry Pi Zero W 1.1

ralphcorrales wrote:
Tue Jun 11, 2019 7:18 am
Have you succeeded in building OpenJFX for ARM Hard Float? Or don't you need anymore? Apparently, I lack skills to do that...
You don't have to build it, just install it:

apt install openjdk-8-jdk openjfx

and you are good to go.

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