keyboards, controllers and cat bell
Call for cats
Many of us have pets. Cats, dogs, fish, parrots, geckos, egg-eating spiders and other smaller brothers and sisters. Most often it is still cats or dogs. And if a dog that has returned home from a walk can declare itself by barking, then it is not always possible to hear a cat’s meow.
In order to help cats with a quiet meow to declare themselves, and was implemented cat call project based on raspberries. It’s simple – the cat meows, the bell electronics recognize this signal and let the owner of the animal know that the cat is asking to come into the house.

AI is involved here, of course, a rather simple neural network that determines meowing among other environmental sound signals. In addition, the call is connected to the “cloud”, in which the signal is processed.
The external system is placed on the front door. The base, as it is already clear, is Raspberry, in addition, there is also a microphone and an Internet connection. Both the software and the hardware of the project are open, so that all this can be used for your own purposes.
Turning a Typewriter into a Linux Terminal

If you have a typewriter lying around, do not rush to throw it away. It can be connected to a PC and turned into a functioning Linux terminal. True, you will need not only a “raspberry”, but also an Arduino Uno. This is necessary to recognize the entered commands with their output by printing on paper. “Malinka” serves as a link between the machine itself and the Arduino.
The video above shows the connection diagram of the machine using different cables. In addition to hardware, software is also required, which was written by the author of the project. Both hardware and software are open, so all this can also be used for your own purposes. Here
this project with all the necessary data.
iNap Malinka – controller and game device

The number of projects based on “raspberries” is really constantly increasing, now there are probably tens of thousands of them. There are very unusual ones, including iNap Malinka – a controller for controlling a robot, as well as a portable gaming device.
As far as you can understand, the project was created either by a Russian-speaking developer, or by someone who knows at least the translation of the word Raspberry into Russian. The developer with the nickname Leoneq spoke about the project on Reddit.
In particular, he mentioned that the controller was needed to control the robot. NRF24L01 is used as a radio module. In addition, the developer has created a custom motherboard that allows you to use the capabilities of the Raspberry Pi Zero.

Well, besides, the author of the project took care of installing analog sticks, buttons and D-Pad, which, together with Pi Zero, gives the controller the ability to serve as a game console. The software used is RetroPie or Lakka. The case is printed on a 3D printer – its model
as, in fact, the source code for the software for the controller.
Here is the project page Redditwhere the author talks about implementation details.
Device for detecting Starlink satellites

The project was named Tricorder, after the devices from the Star Trek universe, where they were often used. The developer Saveitforparts has assembled his device to detect satellites of the Starlink system, which is gradually expanding, providing communication to all new regions of the planet.
In addition to the “raspberry”, the device also uses an LNB module about a satellite dish. The device is able to detect KU-band radiation from satellites. You can’t connect to the Internet using the device, but tracking the satellites themselves is no problem.
The electronic filling is placed in a waterproof case. Everything is collected, as far as you can see, almost on the knee, but this arrangement also has its own aesthetics, which, of course, will appeal to geeks. Well, if there is a desire, the project can be finalized – information about it
.
Poly Keyboard: mechanical split keyboard with displays in each button

About this keyboard
we already wrote
. As far as you can understand, it has already been brought to mind, so that both halves work (in the summer it was said that only one of them was completed).
There is only one person developing the device, not a team, so he has to do everything from 3D printer layouts to board design. No additional wires or anything else is required – the system is connected to a PC or laptop with a regular USB cable, like other split keyboards of this type.
Each key displays its purpose, which can be easily changed using the software that is familiar to every owner of a split keyboard – QMK keyboard firmware. The advantage of the device is also the fact that it is open. On the author’s GitHub, you can download models for a 3D printer, boards, and other important files. So, if you wish, you can start working on a ready-made platform, modifying it to fit your needs.
Initially, the device was developed based on the STM32F407 microcontroller, but due to the shortage of these elements caused by the pandemic, the author had to switch to another microcontroller, more affordable – the Raspberry Pi RP2040.
OLED displays are not color, but black and white, so the keys should not burn out, as in Optimus. Resolution – 72 * 40 pixels. For beauty, another RGB backlight has been added, as well as another larger display that shows the status of the work on the keyboard. Link to the project page – here.