Projects

Here you can find descriptions of some little projects like a small photoplethysmograph, a true random number generator, seismometers and things like that.
	Restoring a Siemens gamma spectrometer from the late 1950s/early 1960s.
	An AVR-based video controller.
	Debugging and repairing a TM990/100M computer.
	Musings about TI's TMS9900 processor family.
	A really tiny Z80 computer.
	The odyssey of repairing a HP3330B.
	Restoring a wonderful PDP 11/34.
	In September 2011 I suddenly had the urgent need to build a small Z80 computer (my last homebrew Z80 was built when I was in school - more than 20 years ago!). See what came out of this. :-)
	My beloved wife Rikka showed my some "yarnmeters" which are used to measure the length of yarn. We decided that a homebrew yarnmeter would be nice and here you can see the result. :-)
	A couple of weeks ago I bought a wonderful but defective Fluke 8300A digital voltmeter for a mere 18 EUR in an online auction. This page describes my efforts to get this device up and running again.
	One of my beloved Telefunken OMS 811 oscilloscopes dies some time ago - no trace, nothing. This page describes how the device was repaired.
	Now having my own Rubidium based oscillator/clock, I was looking for a way to use this as my master reference, so what I needed was some clever way to compare the performance of different oscillators to this device. I was incredibly lucky when I had the chance to buy a Tracor 527E Frequency Difference Meter. This page describes the device and what was necessary to get it up and running again.
	Since being a child I have been dreaming about having my own atomic clock - not necessarily a cesium primary standard, but maybe a rubidium oscillator controlled device. This dream has now come true! :-)
	A small, Perl based, stack oriented array language called 5. This language combines the main aspects of Forth and APL and is easily portable as well as quite powerful.
	A new 16 bit processor architecture featuring 2056 registers (a bank consisting of 256 times 8 registers and 8 fixed registers), a very (!) orthogonal instruction set and four condition bit controllable branch and subroutine call instructions.
	Restoring an HP 41C programmable pocket calculator.
	Restoring an HP67 pocket calculator.
	A simple TTL modulated diode laser.
	A random noise filter.
	A control stick adapter for analog computers.
	Restoration of an Telefunken OMS 811 oscilloscope.
	A four channel oscilloscope multiplexer.
	Dragontalk - a simple Speech Synthesizer (not only for OpenVMS systems).
	An active DCF77 antenna.
	A simple power supply for a HeNe laser tube.
	The NICE pages.
	A three channel geophone amplifier
	A high resolution flux gate magnetometer
	A precision timing source for synchronizing AD converters, etc.
	A simple short period vertical seismometer.
	An eight channel AD converter.
	A simple Lehman type seismometer and Some seismic events.
	A high performance amplifier for seismic applications.
	A simple power supply for the seismic amplifier.
	How to convert a DECserver 200 into a MIDIserver 200 and control MIDI-instruments from a VAX running VMS, using QIOs. :-)
	A simple but very useable photo plethysmograph for bio-physiological experiments.
	A random number generator using a Thorium radiation source.