Solar panels for sensor nodes

Intro For a while now, I started replacing the dead AA(A) batteries in my sensor nodes with rechargeable NiMH ones. So, since these batteries are rechargeable, I thought, why not trying adding small solar panels for sensor nodes, where light is abundant. Node 27: outside sensor Purpose: outside temperature, humidity, light, pressure sensor. Powered by 2 x AAA 500mAh from Ikea. The solar cell is rated 3V, 125mA and is pointing vertically south and costs… Continue reading

Stop it with the coin cells!

Hey companies making sensors and remotes! (for smart home/home automation and the likes). If you can make a sensor microscopic – fine If it needs to be portable – fine But if it is rather small, but still visible you are not doing anyone any favor by making it as small as possible with a coin cell battery that runs just a few months or even less. If your sensor can run for years and… Continue reading

Step up from 1 AA cell – again

Intro A while ago I have evaluated the powering options for my smart home sensor nodes. One thing was really clear: I would try to avoid small batteries and using anything else besides the common AA(A) sizes. This makes nodes last a long time on a battery that is easy and cheap to find. And I was right about this – the plethora of commercial remotes and sensors that I also used (like the ikea ones)… Continue reading

Ikea TRÅDFRI review

Intro Part of my home automation project I would have some controllable lights, of course. On one hand, I used quite a few LED strips, controlled by dimmer modules. On the other, current technology allows for a plethora of wireless light bulbs.  Philips HUE is probably the biggest and best known because it has existed for quite a long time, but I am not that attracted due to the price. Once Ikea came up with… Continue reading

TP-Link KL50 smart light bulb teardown

Intro When I saw this KL50 wifi light bulb on sale, I thought I want to grab one and see what is inside. A quick search revealed no details about the insides of filament WiFi light bulbs. Short review The light worked well from the start, discovering and connecting it through the WiFi was straight up. It does what it promises, quite a nice diffuse and rather warm light. I have slightly colder lights in… Continue reading

The basil speaks to me – Part 2

This is highly experimental But of course, once the soil moisture is read out, it’s only a matter of time before automatic watering has to happen. Add one beefy (..ish) MOSFET and a small pump You get one basil with automatic watering. The setup now looks like this The watering algorithm Is very simple: I wait until the moisture level drops under a low threshold. Then I go into water mode: as long as the… Continue reading

10002 Server

Intro In my initial thoughts about the smart home system architecture, the server was most likely a raspberry pi: At that time it seemed the PI was apt for it. And a raspberry pi 2 served me well for a while, and then I moved to a pi 3 and everything was good. Until it was not enough… What happened? I had mosquitto and node-red as the main things running. And I added some simple… Continue reading

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

10002 Screens and controls

Intro There is no point in having a smart home if you don’t see interesting information or control things. The traditional way, ever since the concept of smart home came to be, is to have some sort of central control panel for everything. In today’s world, that would be a tablet. In my attempt to do that, I ran into the control panel horror. What else? In parallel to this, I thought about the idea… Continue reading

10002 Zen

Zen At some point I though about building the smallest PCB for a sensor node that I could. Hence, the ZEN was born. The PCB is small enough to fit on a holder of 2 AA batteries. Where I have only build a few of these. Here is one reading the soil moisture sensor on basil. Here is another one chilling in the fridge, reading a temperature sensor. And here is one replacing the alarm… Continue reading