• Category Archives english

  • Ludlum Model 2A 500K cpm mod

    Posted on by Johan

    ludlum500krange

     

    I recently bought a Ludlum Measurements model 2A survey meter on eBay from Obtanium. This is a nice meter which features the well known rugged Ludlum design, adjustable HV and 3 ranges of 500, 5000 and 50000 counts per minute.

    Using a scintillation probe the meter easily saturates on the 500 cpm scale, and the 5k and 50k ranges are also overloaded with certain sources.

    So I thought of adding a 500k cpm range. I already read the manuals and associated schematics to find out how to do this.

    Ludlum model 2 and 3 offer about the same functionality and basically share the same PCB, circuit, knobs and switches. Depending on age and model there are certain differences, but a lot of the stuff and functionality is the same. Continue reading → Post ID 1165


    Electronica english wetenschap/science 📎and tagged

  • Access bridged modem using Cisco router

    Posted on by Johan

    I have a Cisco 1811 with a Zyxel P2812HNU-F1 VDSL modem connected to it in bridge mode. The Cisco gets the public IP address through DHCP.

    I wanted to access the modem on it’s local IP address of 192.168.1.254. At first, this didn’t seem possible because all traffic out of the WAN interface is translated to the public IP address. To enable access to the modem I did the following:

    First, I added a secondary IP address to the WAN interface, Fastethernet0:

    interface fastethernet0
ip address 192.168.1.100 255.255.255.0 secondary

    Then I added a nat pool to translate internal traffic with 192.168.1.100:

    ip nat pool nat_to_modem 192.168.1.100 192.168.1.100 netmask 255.255.255.0

    The global NAT command requires an access list to match traffic that is to be NATted. Here I define that all traffic to 192.168.1.0/24 is to be translated:

    ip access-list extended nat_to_modem
 permit ip any 192.168.1.0 0.0.0.255
 deny   ip any any

    Continue reading → Post ID 1165


    computers-networking english 📎and tagged

  • Thrash metal appreciation post

    Posted on by Johan

    I grew up listening a lot of metal. When you are young you will get easily impressed by all kinds of music. I used to listen to highly accessible and melodic stuff, such as power metal, gothic metal, black metal with lots of keyboards. I don’t listen to much of that stuff anymore. As I got older I began listening to less technical and melodic music. One of the genres I knew but didn’t interest me in particular was thrash metal. Sure, as virtually every young metal listener I discovered bands like Metallica, Megadeth, Sepultura, Slayer etc…

    My interest in (hardcore) punk music of more recent years brought me back to listening thrash. Similar to punk it is loud, fast, contains anti-establishment lyrics and usually doesn’t dwell too much on the technical stuff.

    Some years ago thrash metal got a revival and showed that there are still a lot of good bands around. Also, some bands decided to use a more humorous approach in the lyrics. Since I like extreme music but often find the lyrics crap (the usual stuff about death, destruction, the apocalypse etc. over and over again) I think this is a good thing because in the end, a lot of people go to gigs to drink some beers and have fun!

    So, here some fine examples of thrash 🙂

    Kreator, one of the big German thrash bands, still raging on after decades:

    Municipal Waste is one of the revival bands and is highly influenced by crossover thrash. Also they make funny lyrics and videos which is GOOD!

    Continue reading → Post ID 1165


    english muziek/music Uncategorized vermaak/entertainment 📎and tagged

  • Eye/oog update post

    Posted on by Johan

    Visual field test

    English summary below…

    De laatste tijd gaat het goed met mijn ogen. Ik draag vrijwel de hele dag een lens en kan dus over het algemeen mijn werk goed doen. Oogdruk was bij de laatste meting 12 dus gaat langzaam omlaag zoals verwacht. De baerveldt implant is steeds minder zichtbaar in het oog omdat alles minder rood is geworden.
    Het laatste gezichtsveldonderzoek (zie boven) liet geen achteruitgang zien. Continue reading → Post ID 1165


    english keratoconus medisch/medical 📎and tagged

  • Old Android phone = cheap IP cam

    Posted on by Johan

    So, I got me a new Samsung phone because my old phone, a HTC Wildfire is rather slow, especially when it comes to websurfing. It also has low crap resolution. I am much happier with the new phone. So, what to do with the old phone? It’s still a small computer with a camera and touchscreen that should be doing something instead of gathering dust in a drawer.

    One of the things I thought of was a webcam for my turtle tank. It currently houses two (I think female) red cheeked mud turtles, kinosternon cruentatum. I wanted to observe how often one of turtles gets out of the water to bask and what the general activity in the tank is.

    I rooted the phone since I thought it would be handy to have root anyway and installed Cyanogenmod V7, an alternative Android version. This custom ROM does not include the Google Play store to install stuff on Google Play so I had to manually flash it. I am quite unexperienced rooting Android phones and installing custom software but I got it working eventually.

    Next I installed IP Webcam, a nice free webcam app. Since it has a webinterface for remote access it is easily accessible with any computer. Being http-based it’s very easy to grab the images over the wireless LAN that the phone is on using a bash script:

    #!/bin/sh
wget http://192.168.64.4:8080/shot.jpg
FILEDATE=$(date)
montage -geometry +0+0 -background white -label "$FILEDATE" ~/shot.jpg /var/www/meuk/schildpadcam.jpg
mv ~/shot.jpg /storage/plaatjesenfotoos/schildpadcam_arch/"$(date +%d%m%y%H%M)".jpg

    This script uses wget to fetch the most recent video frame (the app is capturing video all the time), uses the imagemagick tool montage to visually timestamp the image and outputs a new picture in a publicly accessible folder on my server. Finally, the most recently downloaded picture is renamed with a timestamp in the filename and moved to a archive directory on the server. Continue reading → Post ID 1165


    Electronica english wetenschap/science 📎and tagged