10002 I2C connectors

Intro In my first iteration of sensors I relied on wire connections between sensors and the actual node board. The result for a motion sensor and a temperature and humidity sensor looks like this The problem with that is that during sensor modules assembly run I spend quite a bit of time on the wiring. On top of that, the result is a mess of small wires inside a box. It makes it hard to… Continue reading

The basil speaks to me

Check out part 2, where the basil is watered automatically. Intro Part of my home automation system is monitoring the well-being of various other non-human species around the house. So i started with the plants. Since they are mostly fixed creatures and generally require only water input from humans, monitoring the soil humidity is a good start. How There are quite a few ways to measure how much water is in the soil, some of… Continue reading

GPP-4323 power supply review

Intro I spent quite a bit of time trying to design a digitally controlled power supply. I even have some prototypes and three articles, Part 1, Part 2 and Part 3. One day it hit me: across the years, I built multiple prototypes, spent a lot of time on it and never ended up anywhere. Why? because I did not really need one and I did not have any pressure to build one. So this… Continue reading

New 3D printer

Intro My first 3D printer was a Prusa i3 clone, which I got as a kit, installed and made some changes to reduce noise. It proven to be full of problems. I could never print ABS with it, there were consistent extrusion problems. The glass bed and glue for adhesion took a while to get going, was time consuming and dirty. Some of the 3D printed extruder parts were constantly failing and I had to… Continue reading

The coolness of RGB LEDs

Intro Ahhhh LEDs….don’t we love them? Today there is a huge variety of them. But there is one type I particularly like. These 5 mm RGB diffused LEDs, easily available from various sources and quite cheap (amazon.de, aliexpress, ebay etc). Here’s why I like them They are super bright. According to some datasheet which may or may not be what you are buying from less reputable sources, the green LED peaks at 5000 mcd at… Continue reading

Simple audio mixer

Intro I have one low cost TPA3116 amplifier which has got more usage than I initially thought. I ended up using it in the living room, it provides enough power and burns only 0.7W from the mains while ON, with no signal. So low that I don’t need to worry about shutting it down when there is no signal, so it’s on all the time. So on to the problem: I need to use it with… Continue reading

Analog Discovery USB isolation

Intro Back when I was deverloping the PSU burner, I wanted to have the Analog Discovery isolated from the common ground, to avoid noise and other issues. Since I did not have a way to do this, I ended up using a laptop on battery for measurements. But for long term, I needed to have this isolation. Unfortunately, things that can isolate USB at 480Mbps or faster are too expensive to justify. The solution The… Continue reading

RFM69 output power

Intro As I was mentioning in my 1000.1000 Hardware selection, I have opted for the cool RFM69HW radio module. Weirdly enough, in quite a few sources (big distributor and ebay) the higher power HW module is cheaper. So there ie no reason not to get the higher power module, given quantity discounts. But I want it to operate at lower power most of times. The datasheet does not show any differences at lower power, so… Continue reading