Computer

Rubber duck debugging, Pair Programming and more

Why “rubber ducking’’? While an undergraduate at Imperial College in London, Dave did a lot of work with a research assistant named Greg Pugh, one of the best developers Dave has known. For several months Greg carried around a small yellow rubber duck, which he’d place on his terminal while coding. ( From “The Pragmatic programmer” page 95)

Why rubber ducking?

A very simple but particularly useful technique for finding the cause of a problem is simply to explain it to someone else or even a object. Explain out loud (or in your mind to the duck) what each line of code is doing.
Often while doing so, you will see the problem.

Why Pair Programming?

It is no secret, i like working on a problem alone. Let me do my ‘thing’. But i like the idea of Pair Programming, why?

  • Differences in thinking, gives alternative solutions
  • 4 eyes principle, typo’s will be seen
  • When working with a novice:
    • Teaches the new guy
    • Give the other space to ask stupid questions, maybe they are NOT!
  • The knowledge of the new code is now known to > 1 person!

Art, Computer, Photography

Wacom tablet doesn’t behave

Changed some code controlling my wacom drawing tablet.
I use this one to draw Art, diagrams and touch up photo’s.

When using multiple screens, i had the problem it would stretch the draw area over multiple screens, streching the ratio. Or it took the work screen to work on.

#!/bin/bash
# using xinput here, check post about two mouses/keyboards on one machine

# Use xrandr to check names check 
MONITOR="DP-1"
PAD_NAME='Wacom BambooFun 6x8 Pad pad'

#undo
xsetwacom --set "$PAD_NAME" Button 1 "key +ctrl +z -z -ctrl" 
xsetwacom --set "$PAD_NAME" Button 2 "key e"
xsetwacom --set "$PAD_NAME" Button 3 "key h"

ID_STYLUS=`xinput | grep "Pen stylus" | cut -f 2 | cut -c 4-5`
xinput map-to-output $ID_STYLUS $MONITOR
ID_STYLUS_2=`xinput | grep "Pen eraser" | cut -f 2 | cut -c 4-5`
xinput map-to-output $ID_STYLUS_2 $MONITOR

exit 0

Most of the times i use Krita and Gimp.

Computer

Mikrotik

Switches and access-points

Today i got my RB4011 ! Wooot!

Total tally

  • MikroTik CRS305-1G-4S+IN – Lab
  • MikroTik RB2011UiAS-RM – Office
  • MikroTik hAP AC2 – Studio
  • MikroTik CRS109-8G-1S-2HnD-IN – Attic
  • MikroTik RB4011iGS+5HacQ2HnD-IN – Livingroom
  • NEW (2022-04-02) crs125-24g-1s-in (2022-04-02)

To replace .. 4 SLM2008 and a TPLink switch 🙂

How much fun is this! .. A display on a switch!

I’ll be posting something about connecting an arduino to the serial console using a tcp server later.

Mikrotiks are all you can eat .. And there is a lot of functionality. One of the main features (besides being switches and routers)

  • Openvpn server
  • DIY display connect
  • Proxy
  • Today Vincent mentioned Mqtt plugin (2022-apr-6)
  • https://help.mikrotik.com/docs/display/ROS/Packet+Sniffer sounds interesting also

Installing extra packages

  • Download correct package zip from ( https://mikrotik.com/download )
  • Extract and use file upload
  • Reboot your mikrotik
Computer

Mikrotik Guest Network

I’ve got several AccessPoints in my network.
Using a roaming setup, clients can connect to strongest AP.

For our Folkband i’ve setup same.
With the exception of those clients only being able to connect to the Internet, and not the rest of my Network

  • Virtual Access Point
  • Own subnet
  • dhcp server only for this access point
  • NAT and Firewall rules for access limitation
/interface bridge 
add name=bridgeguest
/interface wireless security-profiles 
add authentication-types=wpa2-psk eap-methods="" management-protection=allowed mode=dynamic-keys name=guest supplicant-identity=MikroTikHAP wpa2-pre-shared-key=guestkey
/interface wireless
add disabled=no mac-address=MACADDRESS master-interface=wlan1 name=guest security-profile=guest ssid=guest station-roaming=enabled wds-default-bridge=bridge wps-mode=disabled
/ip pool
add name=guest ranges=10.5.0.2-10.5.0.250
/ip dhcp-server
add address-pool=guest disabled=no interface=bridgeguest name=dhcpserverguest
/interface bridge port
add bridge=bridgenb interface=guest
/ip address
add address=10.1.0.5/24 comment=defconf interface=ether2 network=10.1.0.0
add address=10.5.0.1/24 interface=bridgeguest network=10.5.0.0
/ip dhcp-client
/ip dhcp-server network
add address=10.5.0.0/24 dns-server=1.1.1.1 gateway=10.5.0.1
/ip dns static
add address=10.1.0.5 name=router.lan type=A
/ip firewall filter
add action=drop chain=input dst-address=10.1.0.5 dst-port=22,80,443,8291,21,23 protocol=tcp src-address=10.5.0.1-10.5.0.254
add action=drop chain=input dst-address=MYNETWORKSHERE/16 src-address=10.5.0.2-10.5.0.250
add action=drop chain=forward dst-address=MYNETWORKSHERE/16 src-address=10.5.0.2-10.5.0.250
add action=drop chain=forward dst-address=MYNETWORKSHERE/16 src-address=10.5.0.2-10.5.0.250
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" ipsec-policy=out,none out-interface-list=WAN
add action=accept chain=srcnat src-address=10.5.0.0/24
Uncategorized

My computer Lab

Our servers came in! (20200612)

Bought some large servers with Vincent.
3 ProLiant ML350 G6 with loads of memory and cores.
My 2 nodes are running Ovirt Virtualisation, connected to a qnap iscsi host using 10gbps SFPs. Vincents server is running Proxmox.

Uncategorized

Domoticz age checker

A script to check the age of sensors.
Sometimes you don’t have a good 433Mhz connection.
Or the battery has died of your sensor.

This script will warn you.

sensoragescript.sh (for cron)

#!/bin/bash
#Call as follows
#sensoragescript.sh <ipdomoticz> <idx-of-sensor> <age-to-test-in-seconds>

now=$(date +%s)
lastupdate=$(curl -s -i -H "Accept: application/json" "http://$1:8080/json.htm?type=devices&rid=$2" |  grep LastUpdate | cut -f4 -d\" )
#echo $lastupdate
seen=$(date -d "$lastupdate" +%s)
#echo $seen
#echo "$(( $now - $seen))"
difftime="$(( $now - $seen))"
if [ $difftime -gt $3 ] ; then
  echo "WARN : too old - $difftime seconds"
  exit 1
else
  echo "OK : $difftime seconds"
  exit 0
fi

Outputs:

./new.sh 192.168.1.1 123 60
OK : 22 seconds

./new.sh 192.168.1.1 123 60
WARN : too old - 69 seconds

check_mk / icinga check

#!/bin/bash
IPDOMO=192.168.1.1
IDX=123
agewarn=300
now=$(date +%s)
lastupdate=$(curl -s -i -H "Accept: application/json" "http://$IPDOMO:8080/json.htm?type=devices&rid=$IDX" |  grep LastUpdate | cut -f4 -d\" )
seen=$(date -d "$lastupdate" +%s)
difftime="$(( $now - $seen))"
if [ $difftime -gt $agewarn ] ; then
  echo "1 \"WARN - Age check Fridge\" realage=$difftime|age=$agewarn Age of fridge"
  exit 1
else
  echo "0 \"OK - Age check Fridge\" realage=$difftime|age=$agewarn Age of fridge"
  exit 0
fi

"If something is worth doing, it's worth overdoing."