Voor mijn vriendin ontwierp en bouwde ik een goedkoop hangmat frame.

Afgewerkte hangmat houder
Afgewerkte hangmat houder

Dit gevezen en in hout. Ik gebruikte drie 7x7x240 cm geïmpregneerde tuinbalkjes, waarvan ik er twee middendoor zaagde. Een tuinbalkje van 7x7x180 cm, ook middendoor gezaagd om de tussensteunen te maken. De opstaande stukken kunnen naar binnen plooien, door gebruik te maken van scharnieren. De tussensteunen moeten dan wel verwijderd worden. De totale prijs voor het hout: 30€. Ongeveer 10€ voor de scharnieren. De vijzen waren er al. Een deftige elektrische verstekzaag is handig om de balkjes in de juiste hoek af te zagen, maar met de handzaag lukte het ook. Ik gebruikte stevige parkervijzen van ongeveer 10 cm lengte. Voor elke verbinding 3 stuks. Voor stukken waar ze te lang waren gebruikte ik parkervijzen van 5cm. Om de inkeping onderaan de lange balk te maken, zaagde ik eerst beide kanten van de inkeping (tot in de helft van de balk) en gebruikte dan hamer en beitel om het hout weg te halen. Om de hangmat te bevestingen boorde ik een gat aan de bovenkant van de opstaande stukken en deed er een touw door en maakte een lus (platte knoop). Deze lus gaat door het oog van de hangmat en haakt dan terug achter de opstaande balk. Om harder op te spannen kan het touw (meermaals) rond de balk gedraaid worden, waardoor de lus kleiner wordt. Deze manier van bevestigen is zeer handig, omdat het stevig is, maar toch gemakkelijk los te maken. Er zijn natuurlijk nog vele andere opties.

Om het ontwerp te bekijken kan je google sketchup gebruiken, wat een gratis 3D tekenprogramma is. Hierin vind je tools om de afmetingen na te kijken en hoeken te meten. Alle suggesties voor verbeteringen aan het ontwerp zijn welkom!

Eventuele verbeteringen in het ontwerp waar ik zelf al aan dacht:

  • onderste balk middendoor zagen, zodat de lengte verstelbaar wordt. Het gevaarte is dan ook iets makkelijker op te bergen.
  • de tussenbalkjes ook met een scharnier bevestingen aan een kant, en aan de andere kant inklemmen, zodat voor het inklappen geen gereedschap nodig is.
  • De opstaande balken opspannen naar de grondbalkjes, zodat het frame steviger is in de breedte richting. Deze verbinding moet enkel trekkracht hebben, dus een stevig touw kan al volstaan. Deze verbinding moet mee kunnen dichtklappen, of makkelijk los te maken zijn.
  • in plaats van de 180cm balk eerst midden door te zagen en dan de juiste hoeken eraf te zagen, beter van de eerste keer onder de juiste hoek midden doorzagen. Dat scheelt 2 keer zagen, aangezien het ontwerp symmetrisch is.

Bekijk het model in Google Sketchup 3D warehouse

Hangmat staander ontwerp

On the intranetsite of a certain company, I found a poll asking the employees what they think about their new communication plan. This is the original poll:

What do you like the most about our new communication plan?

It was biased toward positive feedback, I can only guess why…
I’d like to change it as follows and repeat the exercise.
(you can select up to 3 options – login required to vote)

What do you think about the new communication plan?

  • I think 25€ per year to buy a phone is ridiculous. (33%, 3 Votes)
  • It's worse than before, now I have to pay more myself. (22%, 2 Votes)
  • Why is there push-mail, when most of us don't have a phone that is supported. (22%, 2 Votes)
  • The tarifs are lower, but the budget is also less. (22%, 2 Votes)
  • It's better for me, I now have to pay less. (0%, 0 Votes)
  • I don't care, I don't use my company phone. (0%, 0 Votes)
  • I'm happy about it, because it gives me possibilities I didn't have before. (0%, 0 Votes)
  • Other... please comment. (0%, 0 Votes)

Total Voters: 3

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[update: Obsolete since modem swap]

I promised I would write about the new network topology I realised by using my brand new wireless router. I installed DD-WRT on my new linksys WRT54G2. Now I will show how to configure it, so you don’t need an extra switch in a common telenet configuration. First I will describe the old situation and explain why it is done that way. Next I will describe how I managed to get the same result, using just one device and a bit of configuration magic.

So what is the old situation?

Old situation with separate switch and router
Old situation with separate switch and router. The blue lines are COAX cable, the green one is scart/hdmi, the purple ones are UTP (network) cables.

This is how telenet installs it. They provide an extra hub, to split the connection between the digibox / digicorder and the internet connection. It is necessary for the digibox/digicorder to work, that it can get an external (telenet-internal) ip address from a dedicated range (10.169.*.*). If the hub or switch would be removed, and the digibox/digicorder plugged into the router, it would get a private ip (192.168.1.*), from the routers lan-dhcp range. This is because the usual configuration of cheap router, does not allow to the split its switch-interface between internal and external ranges. It has one fixed WAN (wide area network) port, and the other ports are for the private network.

The new situation

elimination of the hub via VLAN
elimination of the hub via VLAN

This is my current setup. It’s almost the same, but now without a separate device for giving the digibox/digicorder its dedicated external ip address. It is now done using some configuration magic.

I used one of the fixed internal network ports to form a WAN-switch. This can be done by configuring a VLAN where this interface, and the WAN port are combined, which leaves me with only 3 internal fixed network ports. This is enough for me. One for my fixed computer, one for my XBOX360, and I even have on left unused. My other computers are connected to my private network using Wifi.

This is how you configure it using DD-WRT: It is as easy as unchecking, and then checking another checkbox, and saving the settings. (rebooting the router if it doesn’t work the first time)

checking the checkboxes
checking the checkboxes

Click the image to get the full size.  The result is the same as if you would have the extra physical switch in between, only now, it is implemented as a “virtual” switch inside the router.

The advantage

You only need one device, where you used to have two. This saves a UTP cable, a wall-plug, the space to put the switch and lots of energy (= money). I have not calculated how much energy my old setup consumed, and now that the router has died, it is also no longer possible, but I guess that in this case one device consumes less energy than two. If someone has a kWh meter, I will gladly measure the energy consumption. We can than compare and calculate how long it takes before the new router has paid itself back.

What would be the impact if all telenet customers (that have internet + digital tv) changed their configuration? How much energy would be saved? I have always wondered how much energy the telenet customer side setup costs in terms of energy. There are so many boxes in my closet, all plugged in, are they really all necessary?

Last week, my old wireless router died on me. topcom routerActually the power supply stopped working. It was a topcom router, I bought at aldi, for just under 80€ a little more than three years ago. So the warranty had only just expired for a couple of months. It had been acting strang lately, losing dns-caches and disconnecting wired clients, for no obvious reason. I was still very happy with it. It was cheap, fast (108Mbps wireless), secure and reliable. It came with a wifi-usb key too, which I rarely used.topcom stick If someone has a spare 5.0V  DC 2.0A power supply, just let me know 🙂 I used to experiment a lot with that little router. Once I made a parabolic signal director for it, boosting its range to up to 300m.

So last week, I searched for a solution. I wanted a cheap, but comprehensive solution. Something I could use to play with a bit, without spending too much money. I started reading some reviews, and found that the Linksys WRT54GL is a favourite among open source firmware enthousiasts. I found that it looked ugly and was more expensive than the WRT54G2. I found that the WRT54G2 too is supported by DD-WRT, a fully featured open source firmware. So I ordered it from routershop.nl, and two days later, yesterday, it arrived by mail.

This device looks nice, an important point for me, because It lives next to my TV, in the living room.
This device looks nice, an important point for me, because It lives next to my TV, in the living room.

I played with it a bit, but found that out of the box, the possibilities for configuration are rather limited. So I flahed it with the new firmware. This page details the process, which is actually rather painless. There were only two (known) problems I encountered. The first is that the tftp program for sending the new firmware to the device didn’t work under windows Vista. This was not a problem for me, I just booted into XP and everything worked as described. The second problem was that after setting a new password, I couldn’t save any of the settings I wanted to change. I did the 30/30/30 reset, which means pressing the reset button for 90 seconds, while killing and restoring the power to the device after half a minute. After that I was able to configure the device to my liking.

I was very impressed with the possibilities the DD-WRT firmware opens for such a cheap device.

DD-WRT control panel. Very user friendly, every setting at your fingertips.
DD-WRT control panel. Very user friendly, every setting at your fingertips.

In a next post, I will describe the network topology I realized with it. I used to need an extra network-switch to give an external IP to my telenet digibox/digicorder.