Tag Archives: DIY

Printer from calculator, part 2

Continued from part 1. The printer from the calculator is a neat toy, but we want a real USB printer. So, using my new STM32F103 CubeMX USB printer class for communication with the host computer and some tricky INT based … Continue reading

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ARM:0017 – go to sleep clock

This is a “gamers” clock. It sits near the monitor and shows the real time and time computer is on. This is achieved using USB as power supply. Also, the same USB port is used to set the clock. Battery … Continue reading

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ARM:0015 STM32CubeMX screen libraries, part 2

Continued from Part 1. There are lots of different LCD or OLED screens in the market. Typically, it is possible to define 3 types of screens according to interface type: I2C, SPI and parallel data bus. There are also analog … Continue reading

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ARM:0014 STM32CubeMX libraries for sensors and screens

In fact, any new program written for MCU is only copy-paste from older projects. Not real copy paste, but using the same libraries and subroutines. For some upcoming bigger project, I decided to use STM32 microcontroller, this means, I need … Continue reading

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ARM:0013 STM32CubeMX – USB HID keyboard

Now we will build a USB keyboard. This project is based on STM32CubeMX canned example, HID mouse (see previous article). But we will change mouse to keyboard. Both devices are from the same HID class. First we need to change … Continue reading

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Thing to know: Z80 CPU clock

I just only want to send notes to myself. Z80 CPU clock must be 5Vpp and pure TTL levels sometimes are too low for good and stable CPU work. Even this old CPU is very stable at 5Vpp clock, meanwhile … Continue reading

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AM modulation, schematics, lots of transistors and perfect modulation

I was testing various AM radios and noticed that I don’t have a proper AM source. The AM broadcasting station in my region is very scarce and weak. Also, I wanted more options for radio receiver testing. I thought that … Continue reading

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Simple Sinewave generator

There is simple and good way to generate quite pure sine wave: This circuit is not very simple, but results are quite fine: output is pure sine wave. From the other side, this schematics have some minuses: it is hard … Continue reading

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ZX Spectrum inside CPLD

I found an old ZX Spectrum clone made in Soviet Union in the 90′s. It was my computer, I wrote several programs on it and also, I wrote drivers for Epson printer on this hardware. This model has Soviet chip … Continue reading

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AVR USB printer device and teletype

I have old teletype printer T-63 (it is made by RTF in Eastern Germany, clone of old Siemens Teletype). And the idea is about connecting it as USB printer to our-days computer. Easiest way is to connect it using RS232 … Continue reading

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