I found a tool called pv via a Hacker News thread. pv or pipe viewer allows you to view data as it is pulled out of a Unix pipe. This is really helpful when dealing with long running commands. I used it today to check on the progress of encrypting a large tar archive.

$ pv archive.tar.xz | gpg --sign --symmetric - > archive.tar.xz.gpg
6.51GiB 0:08:52 [6.23MiB/s] [======================>       ] 70% ETA 0:03:47

While pv is running you get a progress, time elapsed, speed, a progress bar, 70% complete and an estimation of time until complete.

One of the facilities at campGND is going to be a wireless network. The hope is to have the network running for the majority of the time. I have built a wireless network at a campsite before, that was made easier by having guaranteed bandwidth from a satellite terminal.

The plan is to have a wireless network for the campsite served by a MikroTik . Using a wireless bridge to reach to the farmhouse. The farmhouse is out of site of the fields we are planning to use. Instead of having wifi doing the full jump I am going to run ethernet as far as possible.

At campGND we are depending on a few things that could be fickle.

• BT Home Broadband
• A long run of ethernet
• Solar Cells and a battery for network power.

Our final back haul is the BT network the site is pretty off the grid for phone reception so we are stuck with BT. We have to be able to make a long hop form the farmhouse before we can do a wireless link down to the site. The solar cells will provide enough to run wireless access points during the day. I think at night we might be a little drunk to care.

I still need to do some testing of the wireless hardware but the plan is to use the following.

• 100M run of Ethernet.
• Injected POE, then split POE.
• 2x WRT54G's.
• A MikroTik access point.
• Solar Cells for with battery backing for night time.

campGND is coming up and it is time to start talking about my projects for the weekend. With our remote location I thought it would be fun to play with something flaming and dangerous.

Rockets were the first thing that came to mind, I haven't done much with rockets beyond launching fireworks a couple of times. Doing my first launches at campGND would probably slow everything down somewhat. I got myself a starter kit from Model Rocket Shop and some extra motors, for a bigger bang.

Iain and myself went out to Balmedie Beach to have a test run with my new toy. We got a couple of videos of the rockets going up, excuse the portrait slow-mo.

On the first launch the recovery canopy got slightly melted by the rocket motor. This meant we didn't really have any recovery mechanism for the rest of the launches. The beach was pretty deserted in the dunes so this wasn't a big deal. At campGND loosing recovery could make things a little tricky.

For campGND I am planning on adding some telemetric data to the rockets, using an Arduino and some sensors. I also want to try adding a camera to the nose cone on a rocket.

For my new business cards I wanted to impose data from an experiment onto the background of an image. For the best results I wanted to render the plot of data onto a transparent png without any axis, values or the standard box.

After a while I got to

> png(filename="transplot.png",width=900,height=400,bg="transparent")
> plot(timestamp[0:1000],snd_cwnd[0:1000],type="h",yaxt="n",xaxt="n",ann="F",frame.plot="F")
> dev.off()

Which generates the following image.

I have been building kernels on my imac in virtual machines. This can take a while and I wanted notifications when the build had finished running.

On my imac

$ while true 
    nc -l 4000 | say
done

This makes netcat(1) wait in a loop for any connections then pipes the output into say(1).

On the vm

$ make buildkernel; echo "Build Complete" | nc -N imac 4000

Replace imac with the hostname or ip of your machine.

I have seen the build side hang and not close the connection until killed, I am not sure why.