Headworx

The IES Annual conference has always been the temple of light. Stunning designs, beautifully illuminated spaces, and the role of light in human wellbeing. In 2025 this has changed. The Gala and the Awards were still about illumination, but the technical sessions started to boldly drift away, to discuss - surprise, surprise - heating, ventilation, and air-conditioning. All with connection to light of course. Or - to be precise - to occupancy sensors brought to buildings en masse thanks to lighting. HVAC is shaping up to be the first significant beyond-lighting application. Forget wayfinding beacons. Forget asset tracking. Forget space utilization heatmaps. It is still all about energy savings. The lighting folks realized the HVAC crowd was unable to pull it on their own. So have come to offer the helping hand: the Lighting-HVAC Integration. As I cried almost 10 years ago - for the connected products to get really connected, we need cross-domain industry experts. And this has been happ...

I've been using iTunes for 25 years. It is a terribly bad piece of software, but one of only a few options to manage a local library of music files with somewhat universal interoperability. In particular the playlists created on an iPod transfer to other Apple (and Windows) computers as well as are recognized by independent local media management and streaming systems like the Sqeezebox Logitech Lyrion . Over the years iTunes has undergone some minor changes (the latest one is nearly as bad as the original), and some of them have somehow (in my case) resulted in the music database becoming corrupted. Long story short, the only way out was to restore the backed-up mp3 files and let iTunes rescan the entire library. The playlists were unfortunately lost this way, as neither the mp3s nor the file folder structure have any information about the playlist metadata. iTunes itself have since moved the root library folder from iTunes Music to iTunes Media (and also some other changes), so...

The post on  Bluetooth NLC vs DALI+: Capacity and Performance has generated very valuable feedback. I promised to shed some more light on my network capacity calculations, so here they are. The key assumptions are: - The Thread network operates at 2.4GHz using IEEE 802.15.4 data links at 250kbps; - Transmitting nodes use Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) method to manage the shared communication channel; - Each unicast transmission is acknowledged - There are two hops (say: sensor → router and router → lighting controller) - The minimum data frame at PHY is 50 octets (+6: preamble + SFD), so ~1.8ms - The ACK frame (including the SIFS time) is ~0.5ms - The average CSMA/CA overhead is ~1.4ms That gives us 3.7ms per hop total. So with two hops we have the channel occupancy of 7.5ms. At full 100% channel occupancy that would give us capacity of 135 end-to-end messages per second (one way). But... 100% would simply kill the network. Thread is very fr...

Whenever I come across a discussion that involves wireless communications over the Thread protocol (such as this one ), there is almost 100% chance people don't understand the underlying physics and traffic patterns. This is the result of Thread marketing since 2014, highlighting the IPv6 protocol as its key strength. And typically it goes like that: "Thread is based on IPv6 and there are more IPv6 addresses that grains of sand in the Universe". And people read this "because Thread is based on IPv6, it is a highly scalable wireless protocol". Treating the potential number of static addresses equally to the dynamic situation when these devices actually send data. If we consider the networked lighting control domain, the most prevalent pattern today is to have a motion sensor in every luminaire. The motion sensor usually has multiple functions: it is a motion sensor of course. But it also is a light level sensor enabling daylight harvesting (or dimming lights down...

Once considered the greatest thing since sliced bread, notifications have spun of of control. Meant to be the (most) important stuff, have been sliding into complete irrelevance. And have become totally distracting and annoying. The operating systems (including the flagship Android and iOS), even with their recent Artificial Intelligence (AI) features have failed to cope with the notifications' torrents. Out of box, every app wants to send notifications about everything - this is of course the fight for potential revenue through engagement and conversion. Yes this can be managed. But only theoretically, as users really drown in the ocean of options they do not understand. On top of the notifications' options there is the hierarchy - you have favorite contacts (meant to always go through), you have time - or activity - based profiles (iOS calls them focuses). Barely anyone understands the combinations. Then there are the super annoying users of (increasingly more popular) instan...

I really liked the Lex Fridman's recent interview with David Heinemeier Hansson (aka DHH) - the 37signals / Ruby on Rails guy. Many topics, but the small teams theme has really resonated with me. I was a solo programmer for about 20 years, starting with Sinclair ZX Spectrum in 1983 and going through several jobs including the company I cocreated in 1992, which grew up to around 300 people ten years later. This solo experience has spoiled me. I was the product manager, the ux designer, the architect and the coder. And that was extremely efficient. Of course the solo approach has limits to the scalability, as there are only 2 hands and 24 hours in a day, no matter how much money you throw in. So at some point I had to give up and cede the tasks to the team. And that was so immensely frustrating. Despite the team being many developers (I still tried to keep the architect role), things started going super slow. I was spending countless hours teaching, explaining, then explaining again ...

Utilities move slowly. But ultimately they do. Half a year ago I installed the Home Assistant multi-channel energy meter which has  clearly shown the energy usage patterns. I had known before my addiction to hot bath every day cost me dearly. And it was really the lowest hanging fruit. Water boiler is the most efficient and available energy storage . After seeing the usage patterns, I was planning to switch to variable energy pricing plan. But filling the related paperwork was tedious enough to procrastinate. Until the utility offered the helping hand: switch to energy pricing with just a single "yes" click on their web site. No paperwork, no nothing.  A couple of days later the confirmation of the switch arrived. Plus I have online access to the formal energy meter readings. No Home Assistant integration yet, but the patterns and values match with what I have, which is reassuring. I need to get used to this a bit (although the main patterns have already been preprogrammed)....