Analysis of electricity usage per year

I started collecting electricity usage data in April 2012, and wanted to check how am I doing this year compared to last year. Of course, as of today, only few months overlap (May-August), but still that will give me some idea if all my energy use optimizations have effect. I started by exporting the daily kWh…

Thoughts on AVR ADC accuracy

I was thinking about the accuracy of the battery measurements the other day, are these accurate or not? I measured the battery using Fluke 27 multimeter and compared that to the readout using the internal bangap method and found a small difference. Googling on the subject revealed that the supposedly 1.1V internal bandgap reference can actually vary.…

CR2032 battery discharge pattern

The Funky v1 + DS18B20 room temperature monitoring project that I installed in our living room on October 31st 2012 has stopped sending. This actually happened few days ago (Aug 10th 2013), but I just noticed it today while checking the graphs. That makes 9 months and 10 days of run time on 220 mAh…

Clapping to control RF power sockets

I did a fun experiment this evening, clap controlling RF power sockets using Funky v2‘s radio module and a sound sensor breakout module. The latter is pretty cheap one, respectively low quality and performance:   It has couple outputs: analog and digital one. The digital output goes HIGH upon audio signal from the microphone reaching…

Door sensor

I have recently purchased a magnetic contact switch to toy with. These are really cheap sensors that are used to detect door (or window) opening/closing events. The principle of work is simple, the sensor consists of two parts: one is a magnet and the other is a reed switch with a smaller magnet attached. Bringing…

Domestic hot water for free

Tricky blog post title, mostly true, but as you know there is no such thing as free lunch 😉 Anyway, those of you following my blog know that I have a Daikin air-to-air heat pump hacked into air-to-water solution for my place. As a bonus I get domestic hot water for both heating and cooling…

Rock-solid RFM2Pi gateway solution

I have had a good share of frustration with damaging Raspberry Pi SD cards due to wearing out/improper shut downs as a result from power failures and was looking for solution to this sort of problems for a while. At first I thought I had the wrong SD cards, then that my power supply wasn’t good,…

Raspberry Pi root file system in read-only mode

I have found my Raspberry Pi running the root file system off a USB flash drive in no good state this morning, the following error showing up on emoncms that was installed locally: Can’t connect to database, please verify credentials/configuration in settings.php Error message: Can’t connect to local MySQL server through socket ‘/var/run/mysqld/mysqld.sock’ (2) Obviously my MySQL…