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by brs
Mon Aug 18, 2014 12:21 pm
Forum: Beginners
Topic: Need programming help (beekeeping)
Replies: 40
Views: 4297

Re: Need programming help (beekeeping)

No, it won't work with those permissions. It needs to be -rw-rw-rw- (the x doesn't matter in this case), or have owner pi instead of root. The pi user doesn't have write permissions to it at the moment. You'll either need to put the uid= option in fstab as mentioned above, or it might work with a u...
by brs
Sun Aug 17, 2014 9:36 pm
Forum: Beginners
Topic: Need programming help (beekeeping)
Replies: 40
Views: 4297

Re: Need programming help (beekeeping)

The words intermixed are just there so I can see what it's doing. When I run it, this is what I get: [email protected] ~ $ ./readscale1.sh light on mounting USB reading ./readscale1.sh: line 17: /mnt/usb/weight.csv: Permission denied umount: /mnt/usb: not mounted I don't understand why the permission ...
by brs
Sun Aug 17, 2014 3:28 pm
Forum: Beginners
Topic: Need programming help (beekeeping)
Replies: 40
Views: 4297

Re: Need programming help (beekeeping)

*Any* form of WiFi? Just exactly how far is the hive from the nearest base station? There is phase 1 of this project, and there is phase 2. Phase 1 involves getting this scale to work when it is plugged into an outlet via a 50' extension cord to a hive in my back yard. In it's current position, it'...
by brs
Sun Aug 17, 2014 3:06 pm
Forum: Beginners
Topic: Need programming help (beekeeping)
Replies: 40
Views: 4297

Re: Need programming help (beekeeping)

So from here, I can either: 1. Try to fix the code that I gave above (which may be better, but I have no idea how to fix it), or 2. Go with my own code, more simplistic, like what scruss suggested. Any suggestions? I think it would be important for you to understand the system well enough to troubl...
by brs
Sat Aug 16, 2014 11:06 pm
Forum: Beginners
Topic: Need programming help (beekeeping)
Replies: 40
Views: 4297

Re: Need programming help (beekeeping)

Is there some form of user interface connected to the PI when you are going to swap the USB sticks? There should be at least a signal to the PI to stop writing to the USB drive and release it before it is being removed, otherwise the data might end up getting corrupted. If you have another device av...
by brs
Sun Jul 06, 2014 6:58 pm
Forum: Staffroom, classroom and projects
Topic: Make Debian Laptop look like Raspbian
Replies: 10
Views: 4043

Re: Make Debian Laptop look like Raspbian

Using a pool of Debian laptops to remotely run applications on a networked Raspberry Pi server or "physical computing" device might also work quite well. Log-in with "ssh -X" and the UI of any application launched on the ssh command-line should appear on the local desktop (module some potential perm...
by brs
Fri Jan 31, 2014 7:46 am
Forum: Automation, sensing and robotics
Topic: Monitoring water temperature in copper pipe.
Replies: 18
Views: 16409

Re: Monitoring water temperature in copper pipe.

The native graph function of RRDTools isn't that CPU intensive either, I get the following CPU usage for the 3 line graph with about 1k samples: time ./graph.sh real 0m1.217s user 0m1.150s sys 0m0.030s Since I am looking at the charts quite rarely, I don't pre-generate the PNG, but run the generator...
by brs
Mon Jan 27, 2014 8:25 pm
Forum: Teaching and learning resources
Topic: Raspberry Pi for science experiments?
Replies: 1
Views: 1972

Raspberry Pi for science experiments?

Given the Raspberry Pi's talent for "physical computing", maybe multi-disciplinary science is a good way to introduce a broad base of students to such flexible/programmable computing tools. Sophisticated data processing that requires programming of some sorts is increasingly needed in all experiment...
by brs
Mon Jan 27, 2014 12:15 am
Forum: Automation, sensing and robotics
Topic: Monitoring water temperature in copper pipe.
Replies: 18
Views: 16409

Re: Monitoring water temperature in copper pipe.

And here are some graphs, dynamically generated from a web.py python web-app with the RRDTool native graph function: http://blog.kugelfish.com/2014/01/raspberry-pi-temperature-data-recorder_26.html . It seems that most of the gaps in the graph, happening sever times per day are caused by this kind o...
by brs
Sun Jan 26, 2014 8:01 pm
Forum: General discussion
Topic: Controlling the Pi from a phone/pc far away?
Replies: 10
Views: 2359

Re: Controlling the Pi from a phone/pc far away?

Are you looking for a direct wireless link or are both the Raspberry Pi & controller connected to the Internet? How far is far? Do you have line of sight between the two?
by brs
Sat Jan 25, 2014 12:16 am
Forum: Automation, sensing and robotics
Topic: Monitoring water temperature in copper pipe.
Replies: 18
Views: 16409

Re: Monitoring water temperature in copper pipe.

Out of curiosity, what are you doing with the data collected from there sensors and how to you process and store it? For now, I am collecting the data in an RRDTool time-series database (see http://blog.kugelfish.com/2014/01/raspberry-pi-temperature-data-recorder_24.html for details). I have been ge...
by brs
Tue Jan 21, 2014 9:07 am
Forum: Automation, sensing and robotics
Topic: Monitoring water temperature in copper pipe.
Replies: 18
Views: 16409

Re: Monitoring water temperature in copper pipe.

Agreed that the tin-foil is more of a placebo, making it easier to hold the sensor in place while improving the thermal coupling between the pipe and the sensor. What would be more important for accuracy is to wrap the whole section with some thermal isolation (e.g. pipe insulation like this: http:/...
by brs
Tue Jan 21, 2014 1:25 am
Forum: Automation, sensing and robotics
Topic: Monitoring water temperature in copper pipe.
Replies: 18
Views: 16409

Re: Monitoring water temperature in copper pipe.

Or make your own fitting for the DS18B20 sensor. The DS18B20 has the advantage that it's trivial to interface with a Raspberry Pi. Analog sensors would probably need an A/D converter of some sorts. E.g. here is a very improvised pipe attachment for a DS18B20 with tin-foil: pipe.jpg For some more on ...
by brs
Mon Jan 20, 2014 9:40 pm
Forum: Networking and servers
Topic: Wifi setup with EW-7811Un dongle
Replies: 0
Views: 393

Wifi setup with EW-7811Un dongle

Yet another tutorial for a minimalist configuration as client or access point using the very popular Edimax EW-7811Un USB wifi dongle: http://blog.kugelfish.com/2014/01/wi-pi-80211-networking-for-raspberry-pi.html So far no problems, powered directly over the USB port, connected to a CISCO Linksys E...
by brs
Wed Jun 05, 2013 10:50 pm
Forum: General programming discussion
Topic: Learning Assembly on RPi?
Replies: 11
Views: 10431

Re: Learning Assembly on RPi?

I am sure there are plenty of tutorials out there for learning ARM assembly on a RPi. E.g. this one looks pretty good for a gentle introduction to some of the basic concepts: http://thinkingeek.com/2013/01/09/arm-a ... chapter-1/
by brs
Wed May 29, 2013 8:11 pm
Forum: General programming discussion
Topic: Which Language to Learn?
Replies: 53
Views: 14260

Re: Which Language to Learn?

If you are interested in low-level system programming, C is not a bad place to start. It's a very small/simple language close to the machine - portable assembly meets late 60ies structured programming. I would stay away from C++ until you really understand the fundamentals of pointers, memory layout...
by brs
Tue May 28, 2013 9:16 pm
Forum: General discussion
Topic: connect pi to laptop
Replies: 13
Views: 3205

Re: connect pi to laptop

First find out, what you expect the IP address of the pi to be. Is it 169.254.1.2 mentioned above? When you have the address, type in the mac terminal window: ping -c 3 <IP address of pi> You should see something like: macbook> ping -c 3 192.168.1.134 PING 192.168.1.134 (192.168.1.134): 56 data byte...
by brs
Tue May 28, 2013 12:28 pm
Forum: General discussion
Topic: connect pi to laptop
Replies: 13
Views: 3205

Re: connect pi to laptop

I am using connection sharing, when I need Internet access for the Pi (most of the time) and IPv6 link-local addresses with zero-conf auto-discovery (Bonjour) otherwise. Both work quite nicely with my Macbook. Here is a description on how to set up a few modes of Mac <-> Pi direct connections: http:...
by brs
Tue May 28, 2013 12:17 pm
Forum: Staffroom, classroom and projects
Topic: Pi Classroom Setup
Replies: 7
Views: 2370

Re: Pi Classroom Setup

I think this is a very smart way to use Raspberry Pis, but I would recommend looking into installing an X server on the host PCs. I did some experiments, with a Mac as the host ( http://blog.kugelfish.com/2012/09/raspberry-pi-tethering.html ) and while using X over VNC is p-a-i-n-f-u-l-l-y slow, the...
by brs
Mon May 27, 2013 8:29 pm
Forum: Networking and servers
Topic: Regular printer + raspberry = network printer?
Replies: 3
Views: 1438

Re: Regular printer + raspberry = network printer?

This would certainly work quite well, as long as the printer is supported by CUPS, the new Linux printer management subsystem. The Raspberry Pi is generally quiet, low-power, cheap and small enough to be ideal for such a job. In addition to a plain vanilla, you can also easily support zero-conf for ...
by brs
Sat May 25, 2013 11:32 pm
Forum: Networking and servers
Topic: Internet connection monitoring with SmokePing
Replies: 5
Views: 20700

Internet connection monitoring with SmokePing

After some recent outages of our Internet access, I though it might be a nice project to use a Pi to long-term monitor the quality of the our Internet connection.

Here is a description of how to do that with SmokePing:

http://blog.kugelfish.com/2013/05/raspb ... nitor.html
by brs
Mon Jan 28, 2013 9:59 pm
Forum: User groups and events
Topic: Groups/meetings near Zürich?
Replies: 2
Views: 904

Groups/meetings near Zürich?

Does anyone know of any user groups or Raspberry Pi related events around Zürich?
by brs
Tue Oct 30, 2012 9:31 pm
Forum: Beginners
Topic: Raspberry Pi- the saviour of Linux?
Replies: 29
Views: 5739

Re: Raspberry Pi- the saviour of Linux?

We are living at the dawn of the post-PC area. All this PC & desktop stuff may soon be as irrelevant and uninteresting as arguing about the relative merits of Amdahl vs. IBM S/360 mainframes.
by brs
Tue Oct 30, 2012 8:39 pm
Forum: General discussion
Topic: X11 forwarding to a mac window
Replies: 13
Views: 16165

Re: X11 forwarding to a mac window

The standard XQuartz (http://en.wikipedia.org/wiki/X11.app) server also has a full-screen mode (enable in preferences), but no "root in a window" mode. But even in full-screen, it seems to run its own window manager.
by brs
Tue Oct 30, 2012 8:33 pm
Forum: Networking and servers
Topic: Free Raspberry Pi colo server hosting
Replies: 0
Views: 1205

Free Raspberry Pi colo server hosting

http://www.edis.at/en/server/colocation ... spberrypi/

Now that might be starting to get a bit silly ;-)

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