Low, Band and High – pass filters are one of the major components when working with RF. Depending on the application, filters can reduse out noise and unwanted signals, or to limit a transmit signal to a pre-specified frequency band in order to prevent interfering with other signals around. Here I want to describe how to build simple and cheap…
Linux kernel is written in C (and in Assembly in platform-specific portions) language. C language is only one allowed language to write kernel modules. And there is no problem, in most of the cases. But sometimes some stranger things may be required. Let’s see how to use C++ for the Linux kernel modules.
Just built two RS-485 adapters (version 2) and decided to write little note about RS-485 bus (and differential line) theory plus perform some testing of the devices. This material mostly interesting for newbies. In the end of this article you can find a funny way to test this devices 🙂
Sometimes when working with network packets inside the Linux kernel it might be very useful to print packet contents to see what actually going on. Here I’m describing how to print packet from sk_buff structure and analyze this data with Wireshark. In this short note I will not describe capturing of the packets inside the kernel but only show how…
Last time we talked about getting Linux routing table with simple Netlink code. Now it’s time to do more interesting stuffs. Let’s add and delete some routes using power of the Netlink!
From this point my site is also available via https. It was not mandatory, but in modern browsers http sites may be marked as ‘unsecured’ and ‘untrusted’. It may happen that in the nearest future all sites without encryptions will be blocked by default in every popular web browser. I don’t want to be badged as ‘untrusted’ or be…
In this little note I wanna describe simple logging module for C programs in Linux. I’m using this code for years in my projects. This module supports different type of output “targets” – files, syslog and stdout.
In the previous article we discussed monitoring of the network interfaces using netlink. Now it’s time to do something more complex and interesting. Let’s discover how to get and print system routing table like a “ip route” command do.
In the previous article I discribe low noise amplifier for the 21cm band. Today I wanna show you construction of the dish antenna where this amplifier can be used.
This is a second version of the usb to RS485 adapter. Please read this article about the first version. New device is built with ISO3082 and requires less components. Also this device can provide more reliability in some situations.