My Place On The Pale Blue Dot

20110910141849_04 Years ago I rescued an old, two-faced Simplex clock from a dumpster. It is a so-called slave clock: it has no time-keeping mechanism from itself but it receives a 24 volt pulse from a remote master clock once every minute.

Not having rescued the master clock I had to make an hour myself. The first version consisted of a 32.768 kHz chrystal, a 4060 binary counter, a 555 integrated circuit, and some assorted TTL ICs. The idea was to divide the 32.768 kHz time base from the chrystal by some factor and end up with one clock pulse per minute.

This version broke down after 16 years of good service: the rectifier, transformer and probably some other components burnt out for reasons I have not been able to discover. Unfortunately I lost the original schematic and I did not feel like reverse engineering it, so I had to make a new hour from scratch.

I wanted to do it differently this time: in stead of using the frequency of a chrystal, which is prone to temperature-induced drift, I chose to use the frequency of the mains power supply. This frequency can fluctuate in the short run, but the fluctuations cancel each other out over time, so over longer periods of time it is a stable 50 Hz. No need to adjust the clock but twice a year for summer- and wintertime.

Last Updated on Sunday, 27 November 2011 15:16

Making a new kite reel

20111016142400_023 The making of this kite reel was inspired by a similar model I saw at a kite festival in Scheveningen, a couple of weeks ago. But in stead of building it from plywood I chose polypropylene, or polypropene - PP for short. It's a thermoplastic polymer that is easy to cut, saw and file and it is insensitive to moisture.

The sides are 25 cm in diameter and about 9 mm thick. They are made from kitchen cutting boards that I purchased at a local general store for about € 3 a piece.

In the left side plate I cut a hole with a diameter of 14,5 cm, to stick my hand through. Both side plates have three elongated gaps, to save weight and to function as an attachement for a carabiner. These holes also make the reel visually more attractive, IMHO.

I used a fretsaw for all the holes because it gives me more control than a jigsaw. A bandsaw would probably the most conveniet and time-saving, but I don't own one.

In the middle of the right side plate I attached a wheel from an inline skate: these have ball bearings for smooth operation and they offer a good handhold. The wheel is kept at a small distance from the right side plate with a little piece of aluminium pipe that goes over the attachment bolt.

Last Updated on Saturday, 22 October 2011 08:46

When I learned that the new heating appliance I had installed in my home communicates with the room thermostat using an actual protocol (as opposed to 'switch on'/'switch off' commands) I became very interested in finding out if it would be possible to listen in on those communications and do interesting stuff with it.

The protocol in question is called OpenTherm (TM). From the OpenTherm website: "OpenTherm is the name of a non-manufacturer-dependent system of communication between modulating HVAC heating appliances and room thermostats. The system consists of a communication protocol and an interface specification. OpenTherm is futuristic system, which combines simple installation techniques with high functionality and future expansion possibilities.".

It seemed that nobody in the Arduino community had tried to read it yet, so that made it an interesting challenge.

Last Updated on Sunday, 30 October 2011 14:37

Powersled L 3.0 kite Some time ago I bought a Powersled kite (pictured right), a medium sized, single line lifter kite. It's a great kite with a considerable pull, and I decided to take advantage of that and build something to lift a digital camera up high to take aerial panoramic photographs.

This article describes the build of a so-called 'AutoKAP rig': a rig that holds a digital camera, programmed to perform an automatic sequence of panning, tilting and picture taking without intervention from the ground. The idea is to take the kite and the rig to a place of interest and then make a bunch of aerial photographs (and hope that some are not too blurred).

Last Updated on Monday, 17 October 2011 05:46

Work in progress: photo galleries

I'm regularly uploading selections from my photo collection.

Latest additions

18 September 2011: I visited the annual kite festival in Scheveningen. Here's some footage.
September 2011: here is a new gallery about our visit to the beautiful city of Istanbul.
August 2011: added a gallery with photos from the annual fireworks show in Scheveningen in the Events category.
May 2011: a couple more KAP pictures taken at Vlieland.
2 April 2011: for various reasons not much has happened in the way of new albums, but today I finally had a KAP opportunity again! The weather wasn't optimal but I got a couple of nice photos nonetheless.
May 2010: check out my new and awesome Kite Aerial Photography photo gallery, made when on holiday on the island of Vlieland.
February 2010: started 'The Daily Snapshot' photo galleries. The intention is to take and publish one photograph, every day. The subject can be anything and everything. I'm usually only packing a small camera and the photographs will be made 'as I go along' - hence the 'snapshot' qualifier .

Last Updated on Sunday, 18 September 2011 17:39