Update: Display TTN-Gateway status

After migrating my TTN gateway to the new The Things Stack Community Edition (see previous blog post) my script to display the gateway status stopped working. The reason behind was, that the new stack does not provide the noc api which was used in the script.

After searching in the TTN forum I found the thread New API for gateway mapping, status and info. Using this API I just need to change one line in my script and now it works again.

-  cmd = "curl -s http://noc.thethingsnetwork.org:8085/api/v2/gateways/eui-b827ebfffe06902a | jq -r '.timestamp'"

+  cmd = "curl -s https://mapper.packetbroker.net/api/v2/gateways/netID=000013,tenantID=ttn,id=eui-b827ebfffe06902a | jq -r '.updatedAt'"

The updated script is available in the github repo.

Photovoltaic dashboard with Grafana

I have a SolarEdge Inverter which is monitored by a energy meter (SolarEdge SE-MTR-3Y-400V-A). The energy meter gets measurements from the inverter and measures voltage and current at the house entry point.

SolarEdge provide a monitoring service and a mobile app to monitor the system. An example is shown here:

To be able to monitor and evaluate the measurements by myself I use the following applications:

• mbmd - to read the measurements from the inverter and energy meter
• nodered - to calculate some derived values 
• mqtt - to "transport" the measurements between the apps
• telegraf - to write the measurements into influxdb
• influxdb - to store the measurements
• grafana - to display the measurements

The result looks like this (a snapshot is available here):

Configuration 

mbmd

The mbmd reads the measurements from the inverter and (via the inverter) from the energy meter.

pi@racknode:/etc $ more mbmd.yaml
# REST api, use 127.0.0.1 to restrict to localhost
api: 0.0.0.0:8080

# mqtt config
mqtt:
  broker: my.mqtt.server:1883
  topic: mbmd
#  user:
#  password:
  clientid: mbmd
  qos: 0
  homie: ""
  # homie: homie


# adapters are referenced by device
adapters:
- device: inverter.ip.addr:1502

# list of devices
devices:
- name: inverter
  type: SE
  id: 1
  subdevice: 0 # use subdevice to access SunSpec subdevices
- name: powermeter
  type: SE
  id: 1
  subdevice: 1 # use subdevice to access SunSpec subdevices

Node-Red

To calculate the "self consumption" and split the measured power in Import/Export I create a Node-Red flow:

Here is the corresponding flow code.

Telegraf

The telegraf is configured to transfer the mqtt messages to the influxdb. 

The config is available here.

Grafana

A snapshot of the dashboard is available here and also the dashboard.json is available.

HP MFP M754DN Fix "Scan to Network" error

My multifunction printer HP MFP M754DN has the ability to scan to a network folder. The target folder is provided by a samba server running CentOS8. It works with out problem but stops to be able to access the network folder some weeks ago. 

Testing the connection on the webgui results in the message: "Cannot connect to the network folder. Ensure the shared folder name is correct."

To fix it I have added the following lines in the smb.conf file on the samba server.

server min protocol = NT1    
min protocol = NT1

A further analysis of my last update activities showed that this was related to the update of the samba package from samba-4.10.4-101.el8_1.x86_64 to samba-4.11.2-13.el8.x86_64. 

According to Samba 4.11 WhatsNew the "SMB1 is disabled by default" now - and the HP printer unfortunately uses only SMB1. With the mentioned settings you enabled the SMB1 protocol again.

A 3d printable case for a ZigBee Gateway

I create a 3D model of a case for the ZigBee board.

 

In the cap is a cutout to place a neodymium magnet.

STL files are uploaded to my Thingivers account (link).

TTN-Gateway in a box

During the last days I worked on the installation of my TTN-Gateway into a case. This is the result:

Beside the LoraWAN hardware I have installed an OLED display and 3 sensors (1x Si7021, 2x DS18B20). The OLED display is connected via I2C, the sensors via 1-wire and I2C.

The sensor data is read by Python3 Script and published with MQTT. The OLED is also controlled by a Python3 script. Both scripts run as systemd-service.

The software is available on github.

Setting up a Zigbee2mqtt gateway

Here are the steps I performed to setup a Zigbee2mqtt gateway using a CC2530+CC2591 board and a RaspberryPI 3.

• My RaspberryPI 3 is running

  pi@racknode:~ $ uname -a
  Linux racknode 4.19.42-v7+ #1219 SMP Tue May 14 21:20:58 BST 2019 armv7l GNU/Linux
  pi@racknode:~ $ hostnamectl
     Static hostname: racknode
           Icon name: computer
          Machine ID: confidential
             Boot ID: confidential
    Operating System: Raspbian GNU/Linux 9 (stretch)
              Kernel: Linux 4.19.42-v7+
        Architecture: arm

• My Zigbee board:
  
  
  
  
  

The steps can be structured in three groups:

1. Flash the Z-Stack coordinator firmware on the Zigbee board
2. Install zigbee2mqtt to run on the Raspberry Pi
3. Setup a daemon to run zigbee2mqtt

Flash the Z-Stack coordinator firmware on the Zigbee board

• Connect the Zigbee board with the Raspberry (Note: this is the connection schema for flashing the firmware, while normal operation another connection schema is used.)
  
  

  Name	Raspi	CC2530+CC2591*
  3,3V/VCC	Pin01	P12 Pin02
  GND	Pin39	P12 Pin01
  RESET	Pin35	P12 Pin03
  DC	Pin36	P14 Pin04
  DD	Pin38	P14 Pin05

  *) P12 - 12pin connector, P14 - 14 pin connector
  
  
  
  
  
  
  
  
  
  
• Install the wiringPI library
  

  sudo apt-get install wiringpi

• Install git

  pi@racknode:~ $ sudo apt-get install git
  

• Clone the flasher repo

  git clone https://github.com/jmichault/flash_cc2531.git

• Test the connection

  pi@racknode:~/flash_cc2531 $ ./cc_chipid
    ID = a524.

• Get the firmware - as mentioned above I need the CC2530+CC2591 version. See https://github.com/Koenkk/Z-Stack-firmware/tree/master/coordinator/Z-Stack_Home_1.2/bin/default for the correct version.

  pi@racknode:~/flash_cc2531 $ wget https://github.com/Koenkk/Z-Stack-firmware/raw/master/
  coordinator/Z-Stack_Home_1.2/bin/default/CC2530_CC2591_DEFAULT_20190608.zip

• Extract the archive

  pi@racknode:~/flash_cc2531 $ unzip CC2530_CC2591_DEFAULT_20190608.zip
  Archive:  CC2530_CC2591_DEFAULT_20190608.zip
    inflating: CC2530ZNP-Prod.hex
    inflating: CC2530ZNP-Prod.bin
  pi@racknode:~/flash_cc2531 $

• Erase the CC2531 CC2530

  pi@racknode:~/flash_cc2531 $ ./cc_erase
    ID = a524.
    erase result = 00a6.
  pi@racknode:~/flash_cc2531 $

• Write the new firmware (takes about 2-3 minutes)

  pi@racknode:~/flash_cc2531 $ ./cc_write CC2530ZNP-Prod.hex
    ID = a524.
    reading line 15490.
    file loaded (15497 lines read).
  writing page 128/128.
  verifying page 128/128.
   flash OK.
  pi@racknode:~/flash_cc2531 $ cd ..
  pi@racknode:~ $

Install zigbee2mqtt to run on the Raspberry Pi

Steps based on

• Connecting CC2530
• Running zigbee2mqtt

My steps were

• Connect the Zigbee board with the Raspberry for operation mode
  
  

  Name	Raspi	CC2530+CC2591*
  3,3V/VCC	Pin01	P12 Pin02
  GND	Pin39	P12 Pin01
  TX (R→Z)	Pin08	P12 Pin07
  RX (R←Z)	Pin10	P12 Pin08

  *) P12 - 12pin connector
  
  
  
  
  
  
  
  
  
• Enable UART and disable UART use for Bluetooth by adding following lines to /boot/config.txt

  pi@racknode:~ $ sudo vi /boot/config.txt
  
  enable_uart=1
  dtoverlay=pi3-disable-bt
  

• Disable modem system

  sudo systemctl disable hciuart

• Remove the serial console entry from /boot/cmdline.txt
  Before

  pi@racknode:~ $ cat /boot/cmdline.txt
  dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=...
  

  After

  pi@racknode:~ $ cat /boot/cmdline.txt
  dwc_otg.lpm_enable=0 console=tty1 root=...
  

• Reboot the Raspberry
• Installing the node.js 10.0 repo and install node.js

  pi@racknode:~ $ sudo curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -

  ... and install node.js

  pi@racknode:~ $ sudo apt-get install -y nodejs

• Clone the zigbee2mqtt repo

  pi@racknode:~ $ sudo git clone https://github.com/Koenkk/zigbee2mqtt.git /opt/zigbee2mqtt

  ... and change own to pi

  pi@racknode:~ $ sudo chown -R pi:pi /opt/zigbee2mqtt

• Install the dependencies

  pi@racknode:~ $ cd /opt/zigbee2mqtt
  pi@racknode:/opt/zigbee2mqtt $ npm ci
  
  prebuild-install WARN install No prebuilt binaries found 
  (target=10.17.0 runtime=node arch=arm libc= platform=linux)
  make: Entering directory '/opt/zigbee2mqtt/node_modules/zigbee-herdsman/
  node_modules/@serialport/bindings/build'
    CXX(target) Release/obj.target/bindings/src/serialport.o
    CXX(target) Release/obj.target/bindings/src/serialport_unix.o
    CXX(target) Release/obj.target/bindings/src/poller.o
    CXX(target) Release/obj.target/bindings/src/serialport_linux.o
    SOLINK_MODULE(target) Release/obj.target/bindings.node
    COPY Release/bindings.node
  make: Leaving directory '/opt/zigbee2mqtt/node_modules/zigbee-herdsman/
  node_modules/@serialport/bindings/build'
  
  > serialport@8.0.1 postinstall /opt/zigbee2mqtt/node_modules/zigbee-herdsman/
  node_modules/serialport
  > node thank-you.js
  
  Thank you for using serialport!
  If you rely on this package, please consider supporting our open collective:
  > https://opencollective.com/serialport/donate
  
  
  npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules/
  zigbee-herdsman/node_modules/fsevents):
  npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for 
  fsevents@1.2.9: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"arm"})
  npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules/
  fsevents):
  npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for 
  fsevents@1.2.9: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"arm"})
  
  added 1356 packages from 856 contributors and audited 877179 packages in 220.282s
  found 3 high severity vulnerabilities
    run `npm audit fix` to fix them, or `npm audit` for details

• Fix the mentioned issues

  pi@racknode:/opt/zigbee2mqtt $ npm audit fix
  npm WARN tsutils@3.17.1 requires a peer of typescript@>=2.8.0 || >= 3.2.0-dev || >= 3.3.0-dev || ↵
  >= 3.4.0-dev || >= 3.5.0-dev || >= 3.6.0-dev || >= 3.6.0-beta || >= 3.7.0-dev || >= 3.7.0-beta but ↵
  none is installed. You must install peer dependencies yourself.
  npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules/↵
  zigbee-herdsman/node_modules/fsevents):
  npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.9: ↵
  wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"arm"})
  npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules/fsevents):
  npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.9: ↵
  wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"arm"})
  
  updated 2 packages in 52.752s
  fixed 3 of 3 vulnerabilities in 877319 scanned packages
  pi@racknode:/opt/zigbee2mqtt $
  

• Enter your configuration in /opt/zigbee2mqtt/data/configuration.yaml

  vi data/configuration.yaml

  Enter your settings 

  # MQTT settings
  mqtt:
    # MQTT base topic for zigbee2mqtt MQTT messages
    base_topic: zigbee2mqtt
    # MQTT server URL
    server: 'mqtt://localhost'
    # MQTT server authentication, uncomment if required:
    # user: my_user
    # password: my_password
  # CC2590 is connected to serial line
  serial:
    port: /dev/ttyAMA0
  advanced:
    baudrate: 115200
    rtscts: false 
  

• Start zigbee2mqtt

  pi@racknode:/opt/zigbee2mqtt $ npm start
  
  > zigbee2mqtt@1.7.1 start /opt/zigbee2mqtt
  > node index.js
  
  Logging to directory: '/opt/zigbee2mqtt/data/log/2019-11-30.16-53-43'
  Starting zigbee2mqtt version 1.7.1 (commit #b459c35)
  Starting zigbee-herdsman...
  zigbee-herdsman started
  Coordinator firmware version: '{"type":"zStack12","meta":{"transportrev":2,↵
  "product":0,"majorrel":2,"minorrel":6,"maintrel":3,"revision":20190608}}'
  Currently 0 devices are joined:
  `permit_join` set to  `true` in configuration.yaml.
  Allowing new devices to join.
  Set `permit_join` to `false` once you joined all devices.
  Zigbee: allowing new devices to join.
  Connecting to MQTT server at mqtt://xxx.xxx.xxx
  Connected to MQTT server
  MQTT publish: topic 'zigbee/bridge/state', payload 'online'
  MQTT publish: topic 'zigbee/bridge/config', payload '{"version":"1.7.1",↵
  "commit":"b459c35","coordinator":{"type":"zStack12","meta":{"transportrev":2,↵
  "product":0,"majorrel":2,"minorrel":6,"maintrel":3,"revision":20190608}},↵
  "log_level":"info","permit_join":true}'

Setup a daemon to run zigbee2mqtt

based on zigbee2mqtt - 5. (Optional) Running as a daemon with systemctl

• Create a zigbee2mqtt service

  sudo vi /etc/systemd/system/zigbee2mqtt.service

  enter

  [Unit]
  Description=zigbee2mqtt
  After=network.target
  
  [Service]
  ExecStart=/usr/bin/npm start
  WorkingDirectory=/opt/zigbee2mqtt
  StandardOutput=inherit
  StandardError=inherit
  Restart=always
  User=pi
  
  [Install]
  WantedBy=multi-user.target
  

• Verify that it works

  pi@racknode:/opt/zigbee2mqtt $ sudo systemctl start zigbee2mqtt
  pi@racknode:/opt/zigbee2mqtt $ sudo systemctl status zigbee2mqtt
  ● zigbee2mqtt.service - zigbee2mqtt
     Loaded: loaded (/etc/systemd/system/zigbee2mqtt.service; disabled; ↵
     vendor preset: enabled)

•    Active: active (running) since Tue 2019-12-03 08:35:46 CET; 7s ago
   Main PID: 626 (npm)
      Tasks: 23 (limit: 4915)
     CGroup: /system.slice/zigbee2mqtt.service
             ├─626 npm
             ├─643 sh -c node index.js
             └─644 node index.js
  
  Dec 03 08:35:46 racknode systemd[1]: Started zigbee2mqtt.
  Dec 03 08:35:50 racknode npm[626]: > zigbee2mqtt@1.7.1 start /opt/zigbee2mqtt
  Dec 03 08:35:50 racknode npm[626]: > node index.js
  Dec 03 08:35:53 racknode npm[626]: [..] Logging to directory: '/opt/zigb
  Dec 03 08:35:53 racknode npm[626]: [..] Starting zigbee2mqtt version 1.7
  Dec 03 08:35:53 racknode npm[626]: [..] Starting zigbee-herdsman...

• Configure the autostart of the service

  pi@racknode:/opt/zigbee2mqtt $ sudo systemctl enable zigbee2mqtt.service
  Created symlink /etc/systemd/system/multi-user.target.wants/zigbee2mqtt.service ↵
  → /etc/systemd/system/zigbee2mqtt.service.

• Reboot the Raspberry to verify your setup

  pi@racknode:/opt/zigbee2mqtt $ sudo reboot
  Connection to racknode closed by remote host.
  Connection to racknode closed.
  
  $ ssh pi@racknode
  Linux racknode 4.19.66-v7+ #1253 SMP Thu Aug 15 11:49:46 BST 2019 armv7l
  
  The programs included with the Debian GNU/Linux system are free software;
  the exact distribution terms for each program are described in the
  individual files in /usr/share/doc/*/copyright.
  
  Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
  permitted by applicable law.
  Last login: Tue Dec  3 08:42:26 2019 from 10.0.0.171
  pi@racknode:~ $ sudo journalctl -u zigbee2mqtt.service -f
  -- Logs begin at Thu 2016-11-03 18:16:43 CET. --
  [..] Started zigbee2mqtt.
  [..] > zigbee2mqtt@1.7.1 start /opt/zigbee2mqtt
  [..] > node index.js
  [..] Logging to directory: '/opt/zigbee2mqtt/data/log/2019-12-03.08-44-14'
  [..] Starting zigbee2mqtt version 1.7.1 (commit #b459c35)
  [..] Starting zigbee-herdsman...
  [..] zigbee-herdsman started
  [..] Coordinator firmware version: '{"type":"zStack12","meta":{"transportrev":2,↵
       "product":0,"majorrel":2,"minorrel":6,"maintrel":3,"revision":20190608}}'
  [..] Currently 1 devices are joined:
  [..] 0x00158d00029acb06 (0x00158d00029acb06): MFKZQ01LM - Xiaomi Mi/Aqara smart ↵
       home cube (EndDevice)
  [..] `permit_join` set to  `true` in configuration.yaml.
  [..] Allowing new devices to join.
  [..] Set `permit_join` to `false` once you joined all devices.
  [..] Zigbee: allowing new devices to join.
  [..] Connecting to MQTT server at mqtt://mqtt.thomo.de
  [..] Connected to MQTT server
  [..] MQTT publish: topic 'zigbee/bridge/state', payload 'online'
  [..] MQTT publish: topic 'zigbee/0x00158d00029acb06', payload '{"battery":31,↵
       "voltage":2825,"linkquality":18,"angle":10.55,"side":3}'
  [..] MQTT publish: topic 'zigbee/bridge/config', payload '{"version":"1.7.1",↵
       "commit":"b459c35","coordinator":{"type":"zStack12","meta":{"transportrev":2,↵
       "product":0,"majorrel":2,"minorrel":6,"maintrel":3,"revision":20190608}},↵
       "log_level":"info","permit_join":true}'
  ^C
  pi@racknode:~ $

Links

• https://www.zigbee2mqtt.io/

Update

2020-02-15: Fix error in flash connection table and picture.

ESP Programmer

I put together an adapter board to attach a CP2104 board to ESP8266 and provide auto programming mode.

For further details see the github repository.

ESP8266 based SensorNode

In last weeks I put together a Sensor-Node based on ESP8266. The software part provides:

• the standard WiFiMonitor to setup the WiFi credentials
• a web page to configure the connected sensors
• a web service to read the configuration and current sensor values
• the data are published via MQTT in a format to be feed into a influxdb

The following sensors are supported:

• DS18B20 (multiple)
• BME280
• Si7021

SensorNode configuration page

I designed a board to be put into a USB port with a temperature and a humidity sensor. 

SensorNodeUSB circuit

SensorNodeUSB PCB bottom side

SensorNodeUSB PCB top side

More information can be found in the GitHub repo SensorNode.

ESP-01 + DHT22: Send data to influxdb

My first ESP-01 "system" is running now. It measures temperature and humidity using a DHT22 every 20 seconds and send the data to an influxdb database.

The influxdb is then used by a Grafana instance where I define a panel for the temperature and humidity. Here are the first measurements:

Looks like there where a glitch at about 12:30 - I will have a look how often this happen.
And here is the corresponding ESP code:

[Update] NetCologne DSL Spectrum @Home

After a support call, it is better, but still worse than before.

Download: 2458 kbit/s
Upload: 383 kbit/s

[Update] NetCologne DSL Spectrum @Home

I thought it can not be worse but since yesterday ...

Down: 1113 kbit/s
Up: 636 kbit/s

Setup/Configuration for another Magic Mirror

Note: Unfortunately, a glitch from the TV, which sometimes occurred before, seems now to be manifested. The TV doesn't power on anymore, neither using remote control nor buttons. I couldn't find a faulty component on TV circuit board. I will/have to stop this project. However, I have learned a lot, so it was not wasted time. 

General setup

• Raspberry PI 2
• SEG ArtColor TV 
• PIR module (GPIO 17, 18), IR transmitter (GPIO 4)

The PIR module will detect motion. If a motion is sense the TV will be switched on via the IR transmitter (simulation of IR remote). After a predefined timeout periode without further motion the TV will switched off (to standby).

Install and enable lirc

• install lirc

  sudo apt-get install lirc

• enable lirc module - edit /boot/config.txt

  dtoverlay=lirc-rpi,gpio_out_pin=4,gpio_in_pin=22

• configure lirc - edit /etc/lirc/hardware.conf

  LIRCD_ARGS=""
  ...
  DRIVER="default"
  DEVICE="/dev/lirc0"
  MODULES="lirc_rpi"
  

Setup IR command to power on/off the TV

• learn IR command

  irrecord -d /dev/lirc0 ~/lircd.conf

• copy new file

  sudo cp ~/lircd.conf /etc/lirc/lircd.conf

• edit the name parameter in /etc/lirc/lircd.conf I choose magicmirror
• start lirc

  pi@mamomami /etc/lirc $ sudo /etc/init.d/lirc start
  [ ok ] Loading LIRC modules:.
  [ ok ] Starting remote control daemon(s) : LIRC :.

• check if IR command is available

  pi@mamomami /etc/lirc $ irsend LIST "magicmirror" ""
  irsend: 00000000000043bc KEY_POWER
  

• run lirc service on start up

  sudo update-rc.d lirc defaults

NetCologne DSL Spectrum @Home

In order to document it - and to wallow in self-pity.

Download: 4862 kbit/s
Upload: 639 kbit/s

Ring Clock

At end of 2014 I had enough time to finish my Ring Clock project (or at least push some steps forward).

I used a picture frame as casing. The passepartout serves as rack for the led ring. I have put a circle of red carton in the middle of the led ring. The carton masks the display board and contains a hole for the light sensor. Two thin carton frames act as spacer to put some distance between the glas plate and the led ring. A sheet of sandwich paper is used as diffusor.

The electronic part is assembled of a Arduino Pro Mini (Watterott), a DCF77 receiver (Pollin), a DS1307 RTC module (ebay), a DS18B20 temperature sensor (ebay), a light sensor (GL5528), a 8 digit display - using 8 old VQB18C modules and a driver (ebay) - and a 60 RGB led ring (Watterott).

The source code and further information can be found here.

LED RGB Strip with Web Interface - Update

After some iterations (I hope) I reach a "done" state. The current version contains the following features:

• Web page content depends on current mode - different pages when strip is on or off 
  
• Web page to configure some runtime values (see right screen shot above)
• Fav-Icon(s)

I mounted the LED strip on backsite of a strip of wood and mounted it on the wall with magnets. On the front side I mounted the PIR module.

 

Here you can see the mounted wooden strip in our hallway.

For the electronic part of the project please look at the project site.

Stabiler Vogelhausständer

Die "dunklen" Jahreszeiten sind immer auch eine Zeit, in der ich verstärkt zum Heimwerken komme. Dieses Jahr wünschte sich meine Frau ein Vogelhaus und das brauchte natürlich auch einen entsprechenden Ständer.

Beim Vogelhausdesign habe ich mich an Anregungen aus dem Baumarkt orientiert - da mag jeder selber schauen. Fehlte noch der Ständer - der sollte entsprechend stabil sein und wegen der hiesigen Katzenpopulation eine gewisse Höhe haben.

Zum Aufbau:

• Basismaterial: 4 Kantholz (54mm x 54mm) - in Summe ca. 4m Länge
• daraus dann 
• 6x Fuß bzw. Stabilisierungsstrebe (Länge ca 43cm)
• 1x zentraler Pfosten (Länge nach Bedarf)
• Für das Stabilisierungskreuz dann entsprechende Aussparungen einarbeiten.
  
• Alles verschrauben und verkleben.
  
  
• Schließlich noch das Holz imprägnieren.

Zeitaufwand (ohne Streichen): 2-3h

Jetzt müssen nur noch die Vögel kommen ...