Analog Threshold Relay


This is part of my readout electronics system. This is one of the oldest modules I built that I haven’t desoldered so far. It is an analog threshold relay with voltage reference and amplification. There is a 10V reference voltage feeding into the 10-turn potentiometer on the front panel, this selects the threshold voltage. A lever switch selects whether the input signal is amplified by x10 or just passed through to the comparator.

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Cleaning a LOMO R15 (ЛОМО Р15) Frame


So as mentioned in the preceding article about my LOMO ST-12 (ЛОМО СТ-12) Repair I got a new LOMO microscope! A LOMO R15 (ЛОМО Р15) to be precise, in this post I briefly go over cleaning the main frame of it, as mine was dirty and the mechanical parts were hard to operate. The green stuff is a grease spillage, where the grease liquefied by heating up and spilled all over the microscope.

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LOMO ST-12 (ЛОМО СТ-12) Repair


So I recently got a LOMO R-15 (ЛОМО Р-15) microscope, that badly needs some cleaning and servicing. So let’s start with the XY stage which is a LOMO ST-12. As can be seen from this image it is slightly rusty and really dirty. I basically started by disassembling it and cleaning all parts in the process. There was quite a lot of excess grease and oil on it implying that someone had a go with this before.

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Universal Temperature Controller


I got one of these cheap “REX C100” temperature controllers from Amazon a while back. So I figured I’ll make it usable by building a desk temperature controller with it. Modifying the Controller By default when you buy cheap temperature controllers like this it’s essentially Russian roulette on whether you get one with a SSR driver or a relay output. I happened to get one with a SSR driver, but need a relay for this.

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Monitoring CISCO Catalyst System Utilization with collectd


Someone recently asked me how to monitor the CPU and memory utilization, as well as the peak bandwidth of CISCO Catalyst switches, as I collect those metrics for mine using collectd with the SNMP plugin. Please note that any data definitions in i.e. your types.db need to be synchronized to all other machines that receive the data if you are pushing the data onto a central server. Total Bandwidth This requires the CISCO-C2900-MIB and the following configuration for the SNMP plugin in collectd.

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700mA Linear LED Driver


I built this small linear LED regulator a while back. Initially I built it to upgrade my ОИ-19 microscope illuminator to LED, but I decided to use the remaining light bulbs until they break before I start upgrading it to LED. I used a couple of soviet potentiometers to go with the theme (СП4-1), it’s a simple standard linear current regulator based off two transistors. The gate current can be adjusted with the internal potentiometer, which allows programming the maximum LED current (up to 800mA).

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Sauter L10 (Mobile Laboratory Scale)


Another one of my laboratory scales. It’s a mobile single range 10mg scale with a resolution of 0.01g. Overview There is not much to the Sauter L10. The only user controls are a focus control (on the back) and a zero-point adjustment on the front. The lamp illuminates if the cover is being opened. What I really like is the small weighting pan, which can be removed and is designed to be carried by hand.

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Brief Introduction into Chaotic Dynamics


I have been asked multiple times by various people of what chaotic dynamics are, the general false assumption being that they are random (stochastic) systems. So I decided to write a quick introduction of what Chaos actually is. Chaos The term chaos stems from the systems experiencing irregularities based upon initial value conditions. They are (usually) highly sensitive to initial value conditions, even a slight change as much as \(1\times10^{-12}\) can lead to the system experiencing a completely different behavior after some time.

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Installing NetBSD 9.1 VAX on SIMH


So I wanted a VAX system to play around with, however one that supports modern software. The only real modern operating system running on VAX is NetBSD. The only feasible emulator to emulate the VAX architecture is SIMH. So with that illusion of free choice out of the way, let’s install NetBSD/vax on SIMH! Configuration load -r ka655x.bin set cpu 256m set rq0 ra92 at rq0 dsk1.dsk set rq1 ra92 at rq1 dsk1.

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