Electronics, Radio & antennas

Cheap single-component RF filters

Low, Band, and High – pass filters are major components when working with RF. Depending on the application, filters can reduce output noise and unwanted signals or limit a transmit signal to a pre-specified frequency band to prevent interference with other signals. Here I want to describe how to build simple and cheap single-component (ceramic) filters for your DIY projects.

Electronics, Networking, Software

RS-485 practice and theory

I just built two RS-485 adapters (version 2) and decided to write a little note about the RS-485 bus (and differential line) theory, plus perform some testing of the devices. This material mostly interesting for newbies. At the end of this article, you can find a funny way to test these devices 🙂


Isolated USB to RS485 adapter version 2

This is a second version of the USB to RS485 adapter. Please read this article about the first version. The new device is built with ISO3082 and requires fewer components. Also, this device can provide more reliability in some situations.

Astro tools, Electronics, Radio & antennas, Radioastronomy

Low noise and low cost amplifier for radio astronomy, 21 cm band

21 cm band, also known as the Hydrogen line, is one of the important bands in radio astronomy. Please read this Wikipedia article if you not familiar with the Hydrogen line. Nowadays, even radio amateurs can observe this signal from outer space, thanks to modern hardware. One of the most important parts of any receiver is the antenna and input…

Continue Reading

Astro tools, Electronics

Powerful DC motor driver using IR2110

To control the DC motor’s speed and rotation direction, we need some motor driver. One of the most popular schematics is H-Bridge. For the low current and voltages, we can use some integral solutions like L293D and so on. But if we need more power and reliability, we have to build some custom H-bridge using Mosfet transistors. This type of…

Continue Reading

Allsky camera, Astro tools, Electronics, Software

Autonomous Allsky camera with Raspberry PI. Part 3: shooting night sky in FITS using QHY5-IIM camera

This is the third part of the Allsky cycle. Please read previous articles to get complete information about this project: Part 1. Autonomous Allsky camera with Raspberry PI: an overview. Part 2. Autonomous Allsky camera with Raspberry PI: powering and lightning protection This time I will show my utility and script for shooting the night sky and processing the images.


Isolated USB to RS485 adapter

RS485 is a standard for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. This communication standard is used in a wide range of computer and automation systems. RS-485 is used as the physical layer underlying many standard and proprietary automation protocols used to implement Industrial Control Systems, including the most common versions of Modbus…

Continue Reading

Allsky camera, Astro tools, Electronics

Autonomous Allsky camera with Raspberry PI. Part 1: overview.

Allsky (or weather) camera is one of the most important parts of the modern observatory. It’s important to monitor sky conditions during night observations, especially when the observatory is remote controlled or fully automatic. Different vendors provide different solutions. But all they are share the same problems: very high prices, lack of autonomy (PC is required), and lack of useful…

Continue Reading