I am feeling a bit nostalgic today, so I will bother you with memories of the past – how it all got started when I was 12 years old. For more than 20 years my soldering iron (Weller, of course!), my oscilloscope, my pile of spare components, home-made PCB’s and other stuff has been stashed away in a few boxes in a dark place. Recently in a burst of nostalgia, I grabbed these boxes from the attic and started snooping around. It brought back memories of etching PCB’s in my mom’s backing dish (she hated that!), countless hours of finding the flaw in a circuit I built on a breadboard and assembler programming on home built microprocessor systems just to flash some LED’s or 7-segment displays.
Home Automation on steroids
This is the first in a series of blog posts about my adventures into home automation (HA) land with openHAB and it will be primarily about building and preparing the Linux (Debian) based system. In next articles we will dive into the details of setting up a HA system with openHAB and some other tools. This is focused on my particular setup, but you will most likely pick-up a thing or two to apply to your own environment. Let's go to the process of getting a Linxu system up and running.
Atmel (recently bought by Microchip) has been producing a large family of 8-bit microcontrollers, the tinyAVR and megaAVR series for quite some time. Actually the first Atmel 8-bit AVR was introduced back in 1997. You will probably find AVR's in many household devices throughout your house, from microwaves to coffee machines and some home automation devices.
Like most microcontrollers, they have many I/O options and are quite flexible. Memory however, especially on the ATTiny (tinyAVR) devices, is rather scarce. So I started to write some low-level assembler routines with minimal footprint to do basic stuff for the programs I want to develop, like queueing data, send and receiving serial data, allocating memory, reporting errors, writing EEPROM memory, etc.
In the first article on low speed serial communications for 8-but microcontrollers, we looked primarily at the design principles and message structure. In this second, long overdue, article, we take a closer look at handling a message.
I am designing a simple, robust protocol for universal serial communications between low-level devices and sensors with very limited resources, whether it is over an RS485 bus, Wi-Fi, PLC or otherwise.
A look at the Smart Meter eco system
When moving to a new house, I immediately had a Smart Meter installed (still not sure what's so smart about it...) with the intention to hook-up a device to read the power and gas consumption throughout the day. Well, doing jobs around the house got in the way and a year later I finally started to look into the details of this Smart Meter. After doing some 'research' on Internet, I decided to start at the beginning: the standards for Dutch Smart Meters, since every meter has to comply with those standards.