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by markkuk
Thu Oct 17, 2019 11:10 am
Forum: Python
Topic: Help connecting 2 Pies using socket
Replies: 3
Views: 66

Re: Help connecting 2 Pies using socket

Your server is listening on port 1237 but your client attempts to connect to port 1235. Additionally, are you sure that 'pi2' resolves to the IPv4 address of the server?
by markkuk
Mon Oct 14, 2019 4:11 pm
Forum: Raspbian
Topic: MongoDB on Stretch - E- Unable to locate package mongodb-org
Replies: 11
Views: 251

Re: MongoDB on Stretch - E- Unable to locate package mongodb-org

You need to keep the braces around the arch= option (see man 5 sources.list):

Code: Select all

echo "deb [ arch=arm64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.2.list
by markkuk
Mon Oct 14, 2019 1:29 pm
Forum: Raspbian
Topic: MongoDB on Stretch - E- Unable to locate package mongodb-org
Replies: 11
Views: 251

Re: MongoDB on Stretch - E- Unable to locate package mongodb-org

Did you follow the instructions I did? Are there any pitfalls to look out for or any hints? I installed MongoDB 4.0 following these instructions: https://andyfelong.com/2019/03/mongodb-4-0-6-64-bit-on-raspberry-pi-3/ , and later upgraded to 4.2. You should follow the standard instructions to instal...
by markkuk
Mon Oct 14, 2019 12:30 pm
Forum: Raspbian
Topic: MongoDB on Stretch - E- Unable to locate package mongodb-org
Replies: 11
Views: 251

Re: MongoDB on Stretch - E- Unable to locate package mongodb-org

I don't think Ubuntu supports RPi4 yet. I have MongoDB 4.2 running on a RPi3 with Ubuntu 18.04LTS Server ARM64.
by markkuk
Mon Oct 14, 2019 7:26 am
Forum: Raspbian
Topic: MongoDB on Stretch - E- Unable to locate package mongodb-org
Replies: 11
Views: 251

Re: MongoDB on Stretch - E- Unable to locate package mongodb-org

I have followed the install instructions: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-debian Did you notice the paragraph titled "Platform Support" near the top that states: MongoDB 4.2 only provides packages for 64-bit builds of Debian 9 Raspbian Stretch is a 32-bit OS. If you chec...
by markkuk
Sat Oct 05, 2019 7:23 am
Forum: Beginners
Topic: HDMI to Display Port connector
Replies: 3
Views: 143

Re: HDMI to Display Port connector

A simple cable can connect DisplayPort output to HDMI input, but HDMI to DisplayPort conversion requires active electronics like this device: https://www.ugreen.com/product/UGREEN_HDMI_with_USB_power_to_DisplayPort_Converter_Cable_Support_Resolution_up_to_4K-en.html or this: https://www.amazon.co.uk...
by markkuk
Wed Oct 02, 2019 10:29 am
Forum: C/C++
Topic: Running C/C++ on Raspberry Pi
Replies: 32
Views: 1177

Re: Running C/C++ on Raspberry Pi

The best optimization I can get is with gcc or with Visual Studio? Visual Studio Code is a completely different program from Visual Studio. Visual Studio Code is a cross-platform code editor with plugins that enable IDE-like properties. It doesn't include a compiler for any language. If you write C...
by markkuk
Wed Sep 18, 2019 4:49 am
Forum: General discussion
Topic: Installing Visual Studio Code
Replies: 11
Views: 527

Re: Installing Visual Studio Code

Heater wrote:
Wed Sep 18, 2019 4:36 am
Does anyone know who headmelted is?
GitHub believes he's this guy: https://github.com/headmelted
by markkuk
Wed Sep 18, 2019 4:19 am
Forum: General discussion
Topic: Installing Visual Studio Code
Replies: 11
Views: 527

Re: Installing Visual Studio Code

Andyroo wrote:
Tue Sep 17, 2019 11:44 pm
Have you seen the Headmelted install at https://code.headmelted.com/? I’ve not tried it under Buster.
The latest version doesn't work. Version 1.29 works but it's almost a year behind the current upstream version (1.38).
by markkuk
Mon Sep 16, 2019 10:24 am
Forum: Beginners
Topic: Install Oracle Java on RPi 4
Replies: 2
Views: 174

Re: Install Oracle Java on RPi 4

nielsgeode wrote:
Mon Sep 16, 2019 7:49 am
When I have OpenJDK installed and run it in verbose method I get a ton of output. The problem could be that it requires Oracle Java and not Open Java.
"Verbose" means that you are supposed to get a ton of output. All the messages are tagged "info", so there isn't any problem that needs fixing.
by markkuk
Thu Sep 12, 2019 11:36 am
Forum: Beginners
Topic: List of users and their rights
Replies: 4
Views: 143

Re: List of users and their rights

Try this command:

Code: Select all

lslogins -u
by markkuk
Wed Sep 04, 2019 11:22 am
Forum: Beginners
Topic: No background with programming
Replies: 9
Views: 375

Re: No background with programming

Here are a few Python tutorials for people with no programming experience:
A Byte of Python
Automate the Boring Stuff with Python
How to Think Like a Computer Scientist: Learning with Python 3
by markkuk
Mon Sep 02, 2019 5:56 am
Forum: C/C++
Topic: UART interfacing with "pigpio"
Replies: 2
Views: 188

Re: UART interfacing with "pigpio"

Did you connect the ground pins in addition to TxD and RxD? Remember that electricity flows in circuits.
by markkuk
Mon Sep 02, 2019 5:49 am
Forum: Beginners
Topic: How to use RSP in company
Replies: 25
Views: 1166

Re: How to use RSP in company

kobata wrote:
Mon Sep 02, 2019 1:50 am
Would you teach me what RPF and RPT are? Are they company name?
Raspberry Pi Foundation and Raspberry Pi (Trading) Limited
by markkuk
Mon Sep 02, 2019 5:41 am
Forum: Beginners
Topic: Motor control
Replies: 3
Views: 261

Re: Motor control

this is the error i get:%Run Stepper_Test.py Traceback (most recent call last): File "/home/pi/Downloads/MotorShield-master/Stepper_Test.py", line 14 except KeyboardInterrupt: ^ SyntaxError: invalid syntax You don't have a "try" keyword before "except". See the Python tutorial on exception handling...
by markkuk
Fri Aug 30, 2019 8:45 am
Forum: Advanced users
Topic: real-time kernel on rpi 3b+ for audio application
Replies: 5
Views: 668

Re: real-time kernel on rpi 3b+ for audio application

I realized that the rpi doesn't actually have an hardware real time clock (RTC) nor a High Precision Event Timer (HPET). RTC is used to keep track of the "wall-clock" time while the system is powered off. You can buy an add-on RTC like this: https://shop.pimoroni.com/products/adafruit-pirtc-pcf8523...
by markkuk
Thu Aug 29, 2019 6:57 am
Forum: Python
Topic: problem with sleep, and apending to a file
Replies: 11
Views: 845

Re: problem with sleep, and apending to a file

For the first problem, see the wait_for_edge() function and event callback functions in RPi.GPIO: https://sourceforge.net/p/raspberry-gpi ... ki/Inputs/
by markkuk
Mon Aug 26, 2019 5:43 am
Forum: General discussion
Topic: problems with raspberry pi 4b
Replies: 18
Views: 1563

Re: problems with raspberry pi 4b

I have a 128GB MicroSD card in my Pi4. Any size up to 2TB should work without any problems.
by markkuk
Sat Aug 24, 2019 5:23 pm
Forum: Beginners
Topic: XF86calculator
Replies: 2
Views: 109

Re: XF86calculator

Here's a recent article on setting up custom keyboard actions: https://www.tomshardware.com/news/raspb ... 40215.html

See also the generic Openbox documentation: http://openbox.org/wiki/Help:Bindings
by markkuk
Thu Aug 15, 2019 6:09 am
Forum: Beginners
Topic: Recommendations for development environment
Replies: 7
Views: 522

Re: Recommendations for development environment

Shouldn't be a problem to also get a Pi4. Do you know if it's possible to compile on the PI4 and then simply copy to the PI3? As long as you use the same OS on both there shouldn't be any problems. Just make sure that the necessary run-time libraries are on the target system. Packaging the applicat...
by markkuk
Tue Aug 13, 2019 6:30 am
Forum: Beginners
Topic: 100 msec timer interrupt, input switch interrupt , display 2 numbers on a hdmi screen
Replies: 35
Views: 1172

Re: 100 msec timer interrupt, input switch interrupt , display 2 numbers on a hdmi screen

You must add a space between "def" and "__init__". "def" is a Python keyword that starts a function definition, "__init__" is the name for a class constructor function.
by markkuk
Fri Aug 02, 2019 10:44 am
Forum: Advanced users
Topic: Using RTC module and synchronizing time from the net together
Replies: 7
Views: 451

Re: Using RTC module and synchronizing time from the net together

As I researched, you can use ntpd each time you want and call it to set system time ntpd is a service that runs continuously in the background and keeps your system time synchronised with network time servers. Clearly you don't understand the difference between NTP and ntpd, or between a communicat...
by markkuk
Fri Aug 02, 2019 7:11 am
Forum: Advanced users
Topic: Using RTC module and synchronizing time from the net together
Replies: 7
Views: 451

Re: Using RTC module and synchronizing time from the net together

semih_sky wrote:
Thu Aug 01, 2019 11:30 am
I've searched the differances between ntpd and ntp, after that I've seen ntp will be better for this project.
NTP is a protocol and ntpd is a program implementing that protocol. If you install ntpd you will be using NTP to set your system time.

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