When I first started making AVR modules, there was no Raspberry Pi or ESP8266. Arduino was introduced in 2005, the same year I started with the AVR microcontroller. But I didn’t know of it until many years later.

There weren’t any Wi-Fi enabled microcontrollers at that time. Both Ethernet and Bluetooth interfaces were more expensive, and harder to interface. So I ended up using the good old serial port.

I made my first module with a serial interface in 2007. RS-232 was cheap, and easy to implement.

With RS-232 I got a way of getting data between the microcontrollers and the computer, but I still needed a defined syntax. So I set out to make one, and called it SIOS — Serial Input/Output System.

AVR is a series of microcontrollers from Atmel. Fitted with A/D converters, comparators, timers, interrupts, internal oscillator, and more. Flash memory is used for the main program, SDRAM for variables and EEPROM for values that need to be saved through a power loss. Cheap, fast and easy make them perfect for home automation projects.

Temperature sensor with serial RS-485 interface. Two additional sensors can be connected using 3-pin headers on the circuit board. Uses an AVR ATmega8 microcontroller.

I rebuilt an existing interface module — to be a stand-alone temperature and humidity sensor, with serial RS-232 interface. Uses an AVR ATmega8 microcontroller.

I rebuilt an existing interface module — to be a stand-alone temperature and light sensor, with serial RS-232 interface and some signal LEDs. Uses an AVR ATmega8 microcontroller.

Portal alarm box unit, my main project on technical college.

Serial (RS-232) interface module; providing 6 analog and 2 digital inputs, and 9 digital outputs. Uses an AVR ATmega8 microcontroller.

Serial (RS-232) interface module; providing 15 digital inputs. Uses an AVR ATmega8 microcontroller.

RS-232 interface module, with voltage measurement. Used to communicate with the emergency power off unit in the Rack box project. Installed inside Rack box status panel. Uses an AVR ATmega8 microcontroller.

Light intensity and temperature sensors; with white, green, yellow, red and blue signal LEDs and a buzzer. RS-232 communication. Uses an AVR ATmega8 microcontroller.