Jinvoo SM-SW101-3 Switch teardown

November 28th, 2019 robin Posted in Home, Home Automation Comments Off on Jinvoo SM-SW101-3 Switch teardown

Sometimes people want to see what the inside of a device looks like… so do I! 🙂 So I took apart my new Jinvoo SM-SW101-3 and took some pictures:

I was able to flash it to tasmota easily with tuya-convert and connect it to Home Assistant. :yay:

There’s a template for it too so configuration was a breeze and shortly after I was able to integrate it to home assistant and set up some automations to turn on scenes – I’ve only used two of the three buttons so far so I’ve still got one to play with!

As far as I can tell, the button LEDs are linked to the relays; they cannot be lit independently of the relays. I don’t have anything connected to the relays at the moment, so they click (and draw a little power) when the button is pushed.

With tasmota flashed I measured about 0.5W with all switches off and about 1.3W with all relays on.

Home Automation with Logstash

April 7th, 2014 robin Posted in Home, Just for Fun, Security 3 Comments »

Home automation is a big dream of mine – I’d like to live in a house which makes living just that bit easier… which thinks ahead for me.  First step before automation is data acquisition – the house can’t make any reasonable decisions if it is not self-aware, so I’ve started kitting out our house with sensors.

The hub (home automation system)

As a hub, and home automation software I’ve taken a Raspberry Pi mini computer (about 50EUR) and installed FHEM (a perl home automation software).  I got the COC from Busware (CC1101-OneWire-Clock extension for Raspberry Pi which can send/receive on 868MHz –  65EUR), and the JeeLink (also 868MHz, but for communicating with PCA301 devices 32.50EUR).  I got some radio controlled power switches (FS20 ST-4 and PCA-301 (which also measures power usage at the socket))



There are a lot of products available, but very few which offer real security.  By security I mean “the device I’m controlling can only be controlled by the system” – if anyone were to sit outside our house with the same equipment I have, they could read all the values, and switch any switches without a problem… so I won’t be attaching anything important devices to it any time soon…


Even without any malicious intent, a thermometer failing could cause the heating to go on full, or allow a house to freeze up (unattended) in the winter… there’s a lot of safety implications which need to be thought out before blindly automating your house.


The sensors and RPi etc. all consume electricity and batteries, but their consumption is so minimal in comparison to the savings possible.  In our household alone (two families in one house) we consume about 5000EUR/year of electricity, water and heating oil… a 10% reduction could pay for a lot of hardware and electricity for an intelligent household.

Big Brother

As with all the NSA scandals, meta data is king.  Even if you don’t have personal tracking (RFID chip implanted into every resident…) within the house, or motion sensors, you can infer a lot from a little data: most devices have unique power signatures making it easy to identify if a washing machine or dish washer was turned on, a meal was cooked, or just a cup of tea, or tea for two… a rise in humidity in a room can mean human presence… and the combination of these keys can pretty accurately paint a picture of who is home and what they are doing.  The danger is that once this information is available, and accessible (which it has to be to perform any useful optimisation…) it could also be used for evil…

What do the results look like?

Here’s some screenshots from the Kibana web frontend


Power usage for my desk for a week

Power usage for my desk for a week

Household power consumption over a week

Household power consumption over a week

Temperature in two rooms for a day

Temperature in two rooms for a day

Here’s some slides from a presentation I did at Munich Perl Mongers recently

Improved stand for inductive charger

February 20th, 2014 robin Posted in Home, Reviews Comments Off on Improved stand for inductive charger


A while ago I got an inductive charger (Qi) for my phone (Nexus 4).  It’s a great idea: never fiddling with that little USB plug, just grab it from the table when you go… accept for two things:

  • You have to be pretty precise when placing it, and interacting with the phone (“Oh – I just got a message!”) while it’s on the charger will often stop the charging process..
  • It’s lying flat on your table – not much good to look at

Here’s my solution:

Inductive Charger


It’s just three pieces of wood glued together, a hole through the base for the cable, and the inductive charger stuck to the wedge.  The block on the right keeps the phone at just the right position to charge every time you plonk it on there.

So if any of you manufacturers want to go copy this fantastic design, go ahead, and if you want to keep your karma good, just send me on a copy of the finished product and I’ll be happy to review it for you! 🙂