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…

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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…

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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.

Electronics

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…

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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…

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Linux system development

Simple Linux character device driver

A character device is one of the simplest ways to communicate with a module in the Linux kernel. These devices are presented as special files in a /dev directory and support direct reading and writing of any data, byte by byte, like a stream. Actually, most of the pseudo-devices in /dev are character devices: serial ports, modems, sound, and video…

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Allsky camera, Electronics, Linux system development

Connecting HTU21D temperature/humidity sensor to the Raspberry PI using simple C i2c interface

Previously in my projects, I’m always used well-known DHT22 (AM2302) temperature/humidity sensors. But I found that these sensors are not very stable and subject to hung. In my case, this device is worked for about two weeks and then stops responding until the power is rebooted. This is absolutely unacceptable on some distant and autonomous devices. After some googling, I…

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Astro tools, Electronics

Isolated eqmod adapter for the telescope control

There are popular and quite cheap amateur telescope mounts from different vendors: Sky-Watcher, Celestron, etc. Most of those mounts contain motors and some controller schematic. Users can control these devices in different ways. One way is to use the mount’s hand controller. Another way is to connect to the computer and use some software to control and guide the telescope.…

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