Raspberry Pi Forums

ghellquist

Second post: My project is going to be like a "KeyVault" safe system. The idea is , someone with internet access will goto a website, and place "information" into the database. This information can be anything at all, but once it hits the database, its encrypted. So now a hacker can't read the impor...

ghellquist

Use raspberry as operation system. --> rationale: implementing tcp/ip with trimmings such as ssh needed to access the internet takes at a guess 100.000 lines of code, already there Select a high level programming language, not ASM --> never program in ASM unless you really love it (few do) or absolu...

ghellquist

Is there any way to achieve this transition from server to client or can I register it as both?

Both at the same time. Run the client as one process, the server as a different process.
The small character & in shell starts a command in the background.
// Gunnar

ghellquist

Check out DHCP

One computer on the net as master, possibly the PC.
//Gunnar

ghellquist

Possible cause -- if you mount it as /dev/sda.

The reason is that the /dev/sda might (without any reason known to humans) change into /dev/sdb at any time. It is all in how USB works.
The solution is to mount the disc as UUID instead. (google: linux mount uuid )

// Gunnar

ghellquist

It helped for me to think about the creation of Erlang as a solution to a set of problems. The language design as such came partly as result of that, partly as a result of the culture some of the people doing the work came from. My interpretation of the history (which probably is very inaccurate) ce...

ghellquist

Please go easy. "Students in grades 7-12 are invited yearly to participate in one (1) of the PJAS Regional Competitions" rpiswag -- I believe this might be aiming a bit too high. Crypto is about mathematics most of us do not meet until well into university level. You might be able to find a route th...

ghellquist

Check out this for inspiration. It has what you are asking for: remote sensor with temp and humidity which runs a year on battery, radio communication, central RPI for either storage of database or passin on the net to a central server.

http://openenergymonitor.org/emon/modules/emonTH

// Gunnar

ghellquist

Oops! Hope you can find a solution. Only remember that radar signals runs at speed of light, 299 792 458 m / s. (well, slightly slower). If you need a resolution of a decimeter, you need to clock the measuring function at about 3GHz.

ghellquist

I assume you have checked this page: http://en.wikipedia.org/wiki/DF-1_Protocol There will be a bit of worked involved. Firstly, the hardware part: - the pi used 3.3V signals. - the PLC used Rs232. = this means you will need to have circuits in between, integrated circuits doing this saves a lot of ...

ghellquist

/proc is not a normal folder. You cannot store any files there. Instead /proc is a pseudo file system showing various kernel data, such as running processes on the system. It is one of the ways Linux making "everything is a file" work. It allows programs to read and sometimes modify system data stru...

ghellquist

Yes. That is what swapping is about. Linux does this if you enable swapping. The problem is that things start running very slow.

// Gunnar

ghellquist

Could you be more clear on what you want to achieve, might make it easier to give an answer? - run contiki-os on the raspberry pi - run programs developed for contiki-os on a raspberry pi running linux - develop contiki-os motes on a raspberry - setup a raspberry pi as "central server" for a network...

ghellquist

The standard calculations for this device assumes 1013.25 hPa at sea level. As you read higher pressure, you need to be below sea level

Actual pressure at sea level changes due to wheather.
http://en.wikipedia.org/wiki/Atmospheric_pressure

ghellquist

Sorry, think you are asking the wrong forum. This forum is about Raspberry Pi and some about Linux. Your question is about malware on a windows machine.

ghellquist

Just learnt existence of IPMI and other KVM-over-LAN. Is such a thing in the plans yet for the Pi? You can expect Linux to have solutions to just about any problem. Maybe not exactly the same solution as other platforms. As for KVM-over-Ip: Raspian uses tightvnc for the "server" end in the Pi. This...

ghellquist

Raw images (from Downloads) can be run headless from the beginning using SSH.

NOOBS needs a little "tweak" before first start, see here:
https://github.com/raspberrypi/noobs#ho ... tall-an-os

// Gunnar

ghellquist

Cubytus wrote:Why would I need Putty?
I understood that Rasbpian already had SSH enabled, isn't it the case?

Right. Putty is the SSH terminal you use in your PC, the "other end" so to say.

ghellquist

Does it help with this explanation. You need to run the control loop cyclically, say once every second. It depends on how fast the real world reacts to changes in fan speed. In order for the calculations to be reasonably simple you want the cycle time to be fairly constant, not varying widely from t...

ghellquist

Using a Pi is definitely nice, but sort of a bit of overkill. To control the system you basically need one three position switch per motor (up stop down, left stop right) and to see where it is pointing you can start by looking out the window. A display of direction could be done using a potentiomet...

ghellquist

As for examples of text PLC languages, do a google on "plc instruction list". This is a simple assembler type language which rather easily can be implemented with an interpreter. I would probably implement it as a byte code interpreter: 1) translation phase: the instruction list is read and parsed a...

ghellquist

PLC on raspberry. The important first question to ask is what guaranteed max response time you need from changed input to changed output. In some applications a PLC needs to respond in a few milliseconds. This is difficult to achieve on the Raspberry using an OS, you will need to do some low-level c...

ghellquist

Just thinking here. You probably know something I do not. The standard distributions has a lot of functions and is not minimal. But just about every one of those functions simply sits on the SD card and does nothing until you start them. No RAM memory used, no CPU cycles used. The graphic is not doi...

ghellquist

Please! Accept the user story as told. Don´t kill the messenger. Instead take the story as input on how to make things better. This story and similar ones will happen again and again. The important part for us as a community is to read them as real world experiences. And thank the person for showing...

ghellquist

One suggestion: check out Magpi Issue 19, page 10. There is a lot of information on how to read sensors, log the values, send them on or present them on a web page scattered all over this forum. It takes a bit of training on how to search in order to find the information though. Currently, the prefe...

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