Monitoring CISCO Catalyst System Utilization with collectd

Banner
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.

Read More

700mA Linear LED Driver

Banner
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).

Read More

Sauter L10 (Mobile Laboratory Scale)

Banner
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.

Read More

Brief Introduction into Chaotic Dynamics

Banner
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.

Read More

Installing NetBSD 9.1 VAX on SIMH

Banner
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.

Read More

Mettler P1210 Laboratory Scale

Banner
Aside from my Mettler B5 analytical balance I also have this laboratory scale, by comparison to the Mettler B5 which goes to 200g with 4 decimal places precision, this one goes to ~1.2kg but only with two decimal places precision. The product sticker on the side dates mine back to 1977. The bubble level indicator on mine isn’t working properly (probably deformed or so) and I had to adjust the sensitivity a bit, as it was oscillating too much sometimes.

Read More

Maintenance on a Singer Model 347

Banner
So I got this 1960’s Singer Model 347 sewing machine the other day. The motor of the machine was audibly struggling unless on full power, which indicates dried up grease or other high friction going on inside the machine. Who knows how long this had been sitting around unused. So I figured I’ll give it some servicing first before I do anything with it. Getting the manual My first expectation was that I would need to search and track down a scanned manual on the internet.

Read More

Mettler B5 Laboratory Scale (Analytical Balance)

Banner
So recently I acquired this Mettler B5 laboratory scale from back in the 1950s. Unfortunately the manual isn’t available on the internet, or rather I found that someone scanned and uploaded it to a long gone Sendspace link. Fortunately the construction and workings of Mettler scales from that time period are all similar if not the same. Since it is a mechanical balance, it is important for it to be level and situated on a low vibration surface.

Read More