Raspberry Pi Forums

richrarobi

This is in response to a couple of people that keep pushing the fallacy that using a tool-kit always saves time. Simply not true, now using wrappers does save time, as does keeping GUI function code libraries. define "Always". :| Are you (any of) applying KISS "top down" or "bottom up"? :oops: :uge...

richrarobi

I am really surprised no-one answered this post in three years! Are you getting anywhere with Scala? I like Scala. I spent a lot of time looking for the best language for me. I much prefer the layout style used by Scala, as opposed to the indent style used by Python. I used Java before, but didn't l...

richrarobi

You probably need sudo in front of your command - gives the command supervisor rights. Have a look at some of the articles in the back issues of MagPi magazine...... Note that sudo should be used with care, on Raspbian it is enabled without password (for convenience, whereas most Unix type systems w...

richrarobi

I have found if I am trying to actually get something done it is best to use RISC OS. Conversely, (and not an answer or trying to divert you) I would be interested to know what it is that causes this phenomenon of enhanced productivity? Can you identify what causes it? Would there be any mileage in...

richrarobi

Do the tasks, you wish to run, work as separate programs?

If you really want to run them from one program at the same time, you probably need threading or (preferably) multiprocessing.

richrarobi

Can you try this with python 3: #!/usr/bin/python3 import multiprocessing import RPi.GPIO as GPIO from time import * GPIO.setmode(GPIO.BCM) GPIO.setwarnings(False) debug = 1 # Variables moteur GPIO_SensH = 17 GPIO_SensAH = 27 GPIO_Marche = 18 # Variables encodeur GPIO_Bouton = 26 # SW, 3.3v -> repos...

richrarobi

As in your other post of the same subject, I am fairly sure that your problem is of context. Processes are spawned / forked, etc with the environment, BUT that doesn't mean that the information you set up is copied across. You have to think of the processes as though they are copies on another syste...

richrarobi

This may or not be relevant, but it could be a "context issue" - try with all your GPIO and other relevant configuration code inside the multiprocessed task. (Context issue - as in what parts of the main program get passed over into the subtasks) e.g. code such as the following maybe? import RPi.GPI...

richrarobi

David, Are you really suggesting that people researching such things as: e.g. swarm robotics https://en.wikipedia.org/wiki/Swarm_robotics should eschew the excellent third party tools such as mqtt and zmq, and all the facilities included therein, in order to avoid adding another layer to the computi...

richrarobi

You should look at existing higher level message handling libraries. MQTT, ZMQ, etc then you can spend more time thinking about what you want to communicate. My favourite is ZMQ because it does not need a message broker. (I also like the RPC style of communicating....Each system can perform commands...

richrarobi

Thanks!!! Just proves that everything in computing ( everything else ?) is knowing what question and who to ask.....found these.... http://www.cigarsinternational.com/cigar-101/article/29/salt-test https://ambientweather.wikispaces.com/Humidity+Calibration%2C+Saturated+Salt+Test?responseToken=0db4f1...

richrarobi

Wow! Thanks for your answers, There is a lot to take in.... maybe a short delay while my brain warms up....

richrarobi

I have seen lots of posts and advice over Temperature accuracy, I have my sensehat on a ribbon cable extension.... I have some reason to suspect that my humidity reading is too high. Around 15%. However I cannot prove it. I have cheap humidity instruments to compare the values, but they can't agree,...

richrarobi

I did a search for RPC style solutions. Apparently : MQTT is a PUB/SUB system and doesn't lend itself well to RPC. While you could possibly shoehorn something on top of MQTT to simulate the synchronicity required, you are probably better off looking for a system which provides real RPC semantics. I ...

richrarobi

here is my simple/compact (almost) understandable rpc system using zmq:- reply server to run on each "server" (note I use Python 3.4):- #!/usr/bin/python3 # Filename: zrep.py # from time import sleep import pickle import zmq import zlocal import importlib class Reply: def __init__(self): self.functi...

richrarobi

some interesting stuff here:

http://www.satsignal.eu/raspberry-pi/dump1090.html

richrarobi

I liked mqtt, but not the need for a broker. Have returned to zmq after not liking that thefirst time round. Wrote python classes libraries for Req/Reply and Pub/Sub that I can use thru' multiprocessing Python 3.4 without rewriting code on each machine. I very much like zmq in that that I can update...

richrarobi

I combined the RPC client and server code in a single python program. This means that each system can use the same "core" code. The code also runs local multiprocessed functions, so that the served code and multiprocessed functions can use the same "lock". Not good if the "server" at the other end i...

richrarobi

And if you really want to you can use the method to drive multiple pi's with your choice of mathematical puzzle (nth degree of pi, etc) RichR p.s. I must add that Pi's are ideal for this sort of lab environment use, where you can build a cluster or distributed environment without spending an absolut...

richrarobi

"Everyone" wants a cluster ...ok if you are running a data-centre with a specific range of tediously repeated functions..... For today's ever decreasing size of processors used as increasingly discrete purpose. (i.e. controlling the foot or hand of a robot?), the future (for me) is obviously in netw...

richrarobi

Multiprocessing is tremendous FUN, and properly written, even in Python, you could write that program and still have most of your 4 cores available for other work. With multiprocessing you can also do RPC between systems, all / both of them sitting mostly idle. Counters use up processor time, better...

richrarobi

So, I just wondered if I could combine remote procedure calls to other pi systems with multiprocessing. (Python 3.4) Here it is... main line module name: __main__ parent process: 5151 process id: 5156 function f module name: __main__ parent process: 5156 process id: 5159 c = 1, hello bob Bearing fro...

richrarobi

Be careful around around this asyncio coroutine stuff, I would suggest following along the progress of enhancements in https://www.python.org/. Some of it is still being refined. Looks very interesting, though.

https://en.wikipedia.org/wiki/Coroutine

richrarobi

At the risk of sounding repetitive, I thought there might be some interest in another alternative approach. I was researching RPC alternatives, decided I wanted to use RPC via zeromq (which unlike other messaging systems doesn't require a broker ) After lots of searching I found aiozmq.rpc via async...

richrarobi

Ontological parsimony!

forth go topspeed, alice pure yorick, smalltalk signal revolution.
senseTalk PIKT nice lingo

As long as HEATER is always right we can all be happy.
Calm observation vs tirade of rhetoric? Calm down man.
Some of us just don't LIKE javascript.

Search found 271 matches

Re: Portable GUI C89 Programming.

Re: Scala

Re: Installing modules in Python 3-- Raspbian

Re: CrossCompile Host=RISC OS Target=Linux?

Re: problem in using Arduino as a sensor for Pi

Re: Bug with GPIO.pwm and threads

Re: Bug with GPIO.pwm and threads

Re: Multiprocessing.process RPi.GPIO.PWM

Re: Passing Data and Commands between programs

Re: Pi to Pi communication via ip network

Re: Humidity accuracy

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Humidity accuracy

Re: Passing Data and Commands between programs

Re: Passing Data and Commands between programs

Re: simple sdr on RPi3?

Re: Passing Data and Commands between programs

Re: Raspberry Pi Cluster

Re: Raspberry Pi Cluster

Re: Raspberry Pi Cluster

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