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by topguy
Wed Jun 26, 2019 12:53 pm
Forum: HATs and other add-ons
Topic: Accelerating network software, how?
Replies: 3
Views: 52

Re: Accelerating network software, how?

Running it on a Pi4 instead of a Pi3 is a potential hardware level fix.

You will get better CPU and better Ethernet performance, but if your real bottleneck is SD-card write speed because you have bad design of file/database handling then the real effect will not be great.
by topguy
Wed Jun 26, 2019 11:00 am
Forum: HATs and other add-ons
Topic: Accelerating network software, how?
Replies: 3
Views: 52

Re: Accelerating network software, how?

If you havent identified the bottleneck then its going to be hard to do any effective optimization. I like the command line tool "dstat", it prints out every second an overview of network, cpu and disk-usage. If you can figure out what resource is the critical one for your application then its much ...
by topguy
Tue Jun 25, 2019 3:48 pm
Forum: C/C++
Topic: change data type using C/C++
Replies: 3
Views: 214

Re: change data type using C/C++

I find it unlikely that a system like ZigBee would use such an inefficient method for sending data. Sending "7e" instead of one byte of value 0x7e just wastes half the bandwidth,
by topguy
Tue Jun 25, 2019 2:33 pm
Forum: C/C++
Topic: Issue communicating with /dev/ttyUSB1
Replies: 2
Views: 45

Re: Issue communicating with /dev/ttyUSB1

I think the first attempt will just exit the while loop at once because you don't wait for the modem to reply.
Wrap the while in a 20 iterations "for"-loop that sleep for 100ms every loop.
by topguy
Tue Jun 25, 2019 2:22 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: How to make a screen work for an open source large screen RP4 powered laptop
Replies: 1
Views: 41

Re: How to make a screen work for an open source large screen RP4 powered laptop

Monitors use AC power (I'm not sure if they change to DC inside the monitor and at what point) I would say "no", they all use DC power, the only difference is if the AC/DC converter is inside the monitor or not, that is usually just a design/quality decision. 2. That there is a control board in the...
by topguy
Tue Jun 25, 2019 2:10 pm
Forum: General discussion
Topic: Users via ssh can't scan with Raspbian Buster anymore
Replies: 9
Views: 388

Re: Users via ssh can't scan with Raspbian Buster anymore

I'm curious to what result ls -lR /dev/bus/usb/ gives.. Also the contents of : "/etc/scanbd/scanbd.conf" if you have it. But here is what I think is going on.... There is a subsystem of X-Windows called "dbus" which send messages between a lot of different services etc. One part of dbus is the HAL (...
by topguy
Tue Jun 25, 2019 12:06 pm
Forum: General discussion
Topic: Users via ssh can't scan with Raspbian Buster anymore
Replies: 9
Views: 388

Re: Users via ssh can't scan with Raspbian Buster anymore

Are the "local" users and the "ssh" users the same users or two completely separated set of users.?? And with "local" users you mean users that log into the desktop on a monitor physically connected to the Pi ? You have shown what the local users see, what results does ssh users get ? No specific er...
by topguy
Tue Jun 25, 2019 8:48 am
Forum: General discussion
Topic: Users via ssh can't scan with Raspbian Buster anymore
Replies: 9
Views: 388

Re: Users via ssh can't scan with Raspbian Buster anymore

Do you know which device the scanner identifies as ? Or if its visible in the /dev/ filesystem at all ? I believe this thread might help you, but as I have not any copy of Buster or a scanner there are limits to what I can check. https://unix.stackexchange.com/questions/44308/understanding-udev-rule...
by topguy
Fri Jun 21, 2019 3:45 pm
Forum: Beginners
Topic: Raspbian os, automatic file transfer with web service
Replies: 5
Views: 223

Re: Raspbian os, automatic file transfer with web service

<r>One possible way, not too complicated. <br/> <br/> Install microsofts IIS and enable FTP.<br/> <URL url="http://www.mustbegeek.com/configure-ftp-server-in-windows-server-2012/"><LINK_TEXT text="http://www.mustbegeek.com/configure-ftp ... rver-2012/">http://www.mustbegeek.com/configure-ftp-server-...
by topguy
Fri Jun 21, 2019 2:12 pm
Forum: Beginners
Topic: Raspbian os, automatic file transfer with web service
Replies: 5
Views: 223

Re: Raspbian os, automatic file transfer with web service

I want to transfer this file to a file share on the server. Do YOU control this server ? Is it a Windows or Linux server ? Can you install software on it ? Most file/directory-share protocols ( NFS, CIFS ) are meant to work over LAN. Over internet you can use FTP, SCP, HTTP Post, WebDAV etc. but it...
by topguy
Fri Jun 21, 2019 1:13 pm
Forum: Networking and servers
Topic: Modem dongle on a headless device
Replies: 1
Views: 178

Re: Modem dongle on a headless device

I've always used PPPD for different types of GSM/3G/4G modems, in the pppd config for your connection there is a "retries" value that I have usually assumed would trigger a new reconnection in case of failures. But my modems has never locked up and needed a power-cut to start working again.
by topguy
Fri Jun 21, 2019 12:40 pm
Forum: Beginners
Topic: Raspbian os, automatic file transfer with web service
Replies: 5
Views: 223

Re: Raspbian os, automatic file transfer with web service

I'm unsure where the "web-service" fits in. Its it a web-server you want to transfer the file to ? We need to know what protocol to use to transfer the file to the server. Is the server on the internet or on the same LAN as the Pi ? A web-service on the Pi is not something you typically would use to...
by topguy
Thu Jun 20, 2019 2:42 pm
Forum: Beginners
Topic: Propriety modbus RS485
Replies: 7
Views: 193

Re: Propriety modbus RS485

What programming experience do you have ? And what languages would you consider/prefer to use ?

Or just google "linux modbus library" and take your pick.
by topguy
Thu Jun 20, 2019 2:26 pm
Forum: Beginners
Topic: Clone sdcard to flash an other sdcard
Replies: 4
Views: 123

Re: Clone sdcard to flash an other sdcard

What did you put on the original SD-card ? Did you try to boot with the original card ? Can you run the "fdisk" comand on that card too ? A singe 29GB FAT partition is not how normal SD cards should look for a Pi. A NOOBS card can look like that before you use it to install an OS, but its not much u...
by topguy
Thu Jun 20, 2019 11:53 am
Forum: Beginners
Topic: Propriety modbus RS485
Replies: 7
Views: 193

Re: Propriety modbus RS485

RS-485 is a physical specification for serial communication. You can buy USB-to-RS485 devices that lets you receive/send data the same way you would do with more common UART/RS232 devices.. Or you can buy converters that you can connect to the UART on the GPIO pins.. http://www.rs232-to-rs485.com/ T...
by topguy
Thu Jun 20, 2019 8:18 am
Forum: Beginners
Topic: QR Scanner
Replies: 5
Views: 599

Re: QR Scanner

How have you tested it on the Pi ? What is your end-goal ? My suggestions.. - open an editor on the desktop and then scan a code. - press "ctrl+alt+F2" to open the console, log in there and then scan a code. - on the console or in a terminal window use the program "evtest" to check events from this ...
by topguy
Wed Jun 19, 2019 3:31 pm
Forum: Beginners
Topic: Serial Communication in RPI3
Replies: 30
Views: 704

Re: Serial Communication in RPI3

Can I suggest that you start a little simpler if possible, by just trying to read all the bytes that the device sends. I guess you can turn the meter on manually with a physical button ? Do the manual specify if the meter will automatically start sending data when turned on or when manually entering...
by topguy
Wed Jun 19, 2019 1:24 pm
Forum: Troubleshooting
Topic: Failed to fork (Cannot allocate memory) error
Replies: 1
Views: 71

Re: Failed to fork (Cannot allocate memory) error

Its unclear to me which program that triggers this message. But if memory is full, then memory has been claimed by a process on the system. First step is to figure out which program/process is stealing memory, and then figure out if this is a bug or is caused by you trying to do stuff that demand mo...
by topguy
Wed Jun 19, 2019 10:50 am
Forum: Beginners
Topic: How to get colors in TTY1 (booting in text mode)
Replies: 2
Views: 150

Re: How to get colors in TTY1 (booting in text mode)

What program(s) is printing the text on tty1 and where are they started from ? If they are started from systemd/cron/rc.local then they will not use the settings for user "pi" unless specifically asked to. There are usually an environment variable called "TERM" that specify the capabilities of the t...
by topguy
Wed Jun 19, 2019 10:37 am
Forum: General discussion
Topic: Hostapd CLI in RPi - Adding a patch
Replies: 1
Views: 77

Re: Hostapd CLI in RPi - Adding a patch

Are you sure you need to manually apply this patch ? Its not done automatically when you build LoWS ? Or are you not compiling the whole project but only using parts of it ? Because the patch is probably meant to match the hostapd code inside LoWS ( https://github.com/lows/lows/tree/master/OpenWRT/h...
by topguy
Wed Jun 19, 2019 10:17 am
Forum: Beginners
Topic: Assigning fixed USB ports
Replies: 9
Views: 595

Re: Assigning fixed USB ports

The problem is that FHEM autoconfigures, grabs the primary port and writes to it. Sounds weird if that behavior can not be overridden by a commandline option of other configuration parameter. If its written in Perl then it might no be so difficult to edit the program itself either, any links to the...
by topguy
Wed Jun 19, 2019 7:45 am
Forum: Python
Topic: Writing USB-Serial as a device (Raspberry Pi Zero)
Replies: 1
Views: 194

Re: Writing USB-Serial as a device (Raspberry Pi Zero)

This guide is a bit old but I think it covers the main parts. ( it also sets the serialport up as a login-console, you can skip that part ) https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/serial-gadget My main point is that if you configure the Pi0 as a serial-gadget you ...
by topguy
Wed Jun 19, 2019 7:31 am
Forum: Troubleshooting
Topic: how to turn the raspberry into an intercom that does not use gsm.
Replies: 1
Views: 75

Re: how to turn the raspberry into an intercom that does not use gsm.

Describe your "intercom": - is it one way or two-way sound ? - what distance is it between the units. - What are the networking possibilities ? Ethernet/Wifi ? Why do you think GSM would be the preferred solution in the first place ? Any solution that would use 3G/4G data should work over ethernet/w...
by topguy
Wed Jun 19, 2019 7:22 am
Forum: Beginners
Topic: Assigning fixed USB ports
Replies: 9
Views: 595

Re: Assigning fixed USB ports

What is a CUL/FHEM ?
by topguy
Tue Jun 18, 2019 7:31 pm
Forum: General discussion
Topic: QR code reader
Replies: 5
Views: 282

Re: QR code reader

Ahh. Datamatrix barcodes those are a bit easier to google..

Maybe try this package: https://packages.debian.org/stretch/dmtx-utils

Code: Select all

sudo apt install dmtx-utils
(need to read qr code with ssh commad)
Make up your mind ;-) Datamatrix and QR are not the same thing, they are both 2D barcodes.

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