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by richrarobi
Fri Jul 15, 2016 8:07 am
Forum: General programming discussion
Topic: What programming language to use
Replies: 103
Views: 22036

Re: What programming language to use

As usual, the human brain is so varied and chaotic that it is impossible to get one single answer to the "language" question. But as a crowd, the answer becomes apparent. Look at how many topics and posts there are for "Python" compared to the other languages in this forum... (5759 against 2111 for ...
by richrarobi
Fri Jun 24, 2016 8:07 am
Forum: Automation, sensing and robotics
Topic: Best Amazon Echo Hardware on Pi
Replies: 6
Views: 3948

Re: Best Amazon Echo Hardware on Pi

Maybe I am just feeling grumpy? But, no way would I want to invite an always listening device into my privacy..... plus I don't like vnc (you pays your money, takes your choice) the installation of other software is too complex..... Alexa looks like a fun idea - SciFi control of spaceship, etc. Is t...
by richrarobi
Fri Jun 24, 2016 7:18 am
Forum: Automation, sensing and robotics
Topic: Temperature mesurement via XBee
Replies: 2
Views: 606

Re: Temperature mesurement via XBee

Your post makes it seem you have a pile of parts and wish for someone to do your project? Also not too many people use xbee modules. What have you done so far? Describe. Draw diagram. What works? What doesn't? With more information someone may be able to identify possible problems? For example, if t...
by richrarobi
Tue Jun 07, 2016 7:25 am
Forum: General programming discussion
Topic: Advice needed on programming language choices
Replies: 15
Views: 3062

Re: Advice needed on programming language choices

If you have a pi3, I believe Julia (julialang) is "here at last" - mentioned about twice elsewhere on the forum. I managed to compile last night (about 4 hours with all four cores going) using the standard instructions on github. No errors ..... (note that a heatsink is almost essential for this job...
by richrarobi
Sat May 21, 2016 7:35 pm
Forum: Beginners
Topic: cluster
Replies: 7
Views: 1657

Re: cluster

Another example of RPyC , results :- on 2016-05-21 at 19:06 , Temperature(s) : 19.66 / 19.55 , Humidity : 67.54 , Barometer : 988.66 produced on pi-05 with this:- #!/usr/bin/python3 import rpyc import demjson conn = rpyc.classic.connect("pi-04.local") # use default TCP port (18812) proc = conn.modul...
by richrarobi
Sat May 21, 2016 4:15 pm
Forum: Beginners
Topic: cluster
Replies: 7
Views: 1657

Re: cluster

RPyC is maybe another approach....having tried various messaging solutions, zmq, mqtt, rabbit, I decided I wanted to have one pi with Flask controlling LED's on another, and getting sense information from a third. Here is an example of using RPyC (Remote procedure calls for Python) - from pi-05 to p...
by richrarobi
Sun May 01, 2016 6:31 am
Forum: Networking and servers
Topic: How to send data from raspberry to web server
Replies: 6
Views: 1196

Re: How to send data from raspberry to web server

What do you mean by web server......are you certain yo don't mean web browser? What is your web server???
My guess is that you want your pi to have a web server showing the data from sensors?
Draw us a picture, in words or otherwise.
by richrarobi
Sat Apr 30, 2016 8:44 pm
Forum: Automation, sensing and robotics
Topic: Where is the dedicated Raspberry Pi cloud service?
Replies: 13
Views: 2433

Re: Where is the dedicated Raspberry Pi cloud service?

The internet started out as a closed system, now it is "out of hand" - there are so many routers as well as the official ones that it would probably continue running if the main department of defence sites all stopped. As if that's going to happen. Apply that to an IOT owned by the people. Replicate...
by richrarobi
Fri Apr 29, 2016 3:55 pm
Forum: Automation, sensing and robotics
Topic: Raspberry connect to Mi light
Replies: 1
Views: 519

Re: Raspberry connect to Mi light

Does this help?
if bridge=hub then maybe?

https://github.com/openhab/openhab/wiki/Milight-Binding

If it is relevant, it includes references to arm based linux and to mqtt

p.s. I searched on the web...
p.p.s Regret- mon Francais ne'st pas bon!!
by richrarobi
Thu Apr 28, 2016 9:08 am
Forum: Automation, sensing and robotics
Topic: Where is the dedicated Raspberry Pi cloud service?
Replies: 13
Views: 2433

Re: Where is the dedicated Raspberry Pi cloud service?

it is a nice idea. First of all, there would need to be some kind of agreement over the structure of the data. There are already things like "international earthquake monitoring"...., "weather underground"..., and the like. However, a "global standard" for the structured storage of all telemetry dat...
by richrarobi
Thu Apr 28, 2016 6:33 am
Forum: General programming discussion
Topic: Looking for direction - Read/Update mysql from webpage
Replies: 7
Views: 1572

Re: Looking for direction - Read/Update mysql from webpage

Ref my solution, above: I didn't like the pull solution. I have changed so that the pi with the sense hat publishes a Mqtt message every 5 minutes. This is picked up and stored, currently one line in mongodb on my Linux server. Could be in any db.The flask web page gets the data from the db. This me...
by richrarobi
Sun Apr 24, 2016 12:39 pm
Forum: General programming discussion
Topic: Looking for direction - Read/Update mysql from webpage
Replies: 7
Views: 1572

Re: Looking for direction - Read/Update mysql from webpage

My ajax flask solution - for my own use and to help in this thread? It now works (web pages per my previous post) - This doesn't at present use any database, although I have stored the data on a mongodb server on another machine. This addresses the ajax updating of sensor data on the web page. This ...
by richrarobi
Sat Apr 23, 2016 11:19 pm
Forum: General programming discussion
Topic: Looking for direction - Read/Update mysql from webpage
Replies: 7
Views: 1572

Re: Looking for direction - Read/Update mysql from webpage

Flask is worth a look, framework directly in python. It is easier to use than many of the more traditional web servers. I am currently stumbling through the dynamic ajax forest. The following example worked, but I haven't managed to get my adaptation to work yet...... http://code.runnable.com/UiPhLH...
by richrarobi
Sat Apr 16, 2016 4:41 pm
Forum: General discussion
Topic: CouchDB on the Pi
Replies: 46
Views: 14690

Re: CouchDB on the Pi

Not what I meant. Taxonomy as in classification, not as maybe in object programming. To clarify (maybe) thinking in terms of : e.g. think earth tremors, vibrations, etc. Stored as 'x-pi-y, sensors, tremor' is probably not as useful globally as 'location, sensor, tremor' or something similar. (maybe ...
by richrarobi
Thu Apr 14, 2016 9:30 pm
Forum: General discussion
Topic: CouchDB on the Pi
Replies: 46
Views: 14690

Re: CouchDB on the Pi

re: Python performance sucks : yes, probably - But, I discovered recently that both 2.7 and 3 now support REAL parallel processing without that dreaded GIL.... https://docs.python.org/3/library/concurrent.futures.html#processpoolexecutor So Python doesn't suck quite as much as it did....I tried it -...
by richrarobi
Thu Apr 14, 2016 8:33 pm
Forum: Beginners
Topic: Help with Network Stuff
Replies: 4
Views: 620

Re: Help with Network Stuff

https://www.raspberrypi.org/forums/viewtopic.php?f=36&t=66129&p=tag/ladyada clever clogs! This one might help.... https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=142702&p=943067&hilit=direct+ethernet#p943067 leads to:- https://pihw.wordpress.com/guides/direct-network-connection/ p.s. I have...
by richrarobi
Thu Apr 14, 2016 7:00 pm
Forum: Beginners
Topic: Help with Network Stuff
Replies: 4
Views: 620

Re: Help with Network Stuff

You might need a crossover cable? EUGH!
Normally a network switch or router would be between the two devices. Those handle the polarity of the wires for you. Do you have a router with network ports? Try plugging both systems into that via separate LAN cables.....
by richrarobi
Thu Apr 14, 2016 6:03 pm
Forum: General discussion
Topic: CouchDB on the Pi
Replies: 46
Views: 14690

Re: CouchDB on the Pi

I guess you are right about the node-red, I replaced the flow with half a dozen lines of Python. Less overhead, too......And, I couldn't see how to write functions that were any use, either (not being a javascript wizard). But, I do like the Jupyter IPython interface, (did we already have this conve...
by richrarobi
Sat Apr 09, 2016 9:37 pm
Forum: General discussion
Topic: CouchDB on the Pi
Replies: 46
Views: 14690

Re: CouchDB on the Pi

Thought I might stir this up again. Thinking in terms of "horses for courses", I have a big old linux box (shadow) (nfs server with largish drive) running mosquitto (acting as broker), mongodb and node-red. Node-red did run on pi-05 but it seems more sensible on shadow. I was pleased to find that it...
by richrarobi
Thu Apr 07, 2016 8:12 pm
Forum: Beginners
Topic: Beginner needs some help please
Replies: 25
Views: 3832

Re: Beginner needs some help please

I often think that the hardest part of knowing the answer is realising there was a question in the first place. RichR p.s. Another bit of code? import paho.mqtt.publish as publish import demjson from time import gmtime, strftime, sleep from sense_hat import SenseHat try: while True: # dt = strftime(...
by richrarobi
Thu Apr 07, 2016 5:19 pm
Forum: Beginners
Topic: Beginner needs some help please
Replies: 25
Views: 3832

Re: Beginner needs some help please

2) i thought that subscribing a topic at least would have shown the last message published on that topic, but with "mosquitto_sub" i can only see new messages published, is that right? is that the way mqtt works? Dougie mentioned QoS (Quality of Service) in an earlier post: this effects the deliver...
by richrarobi
Wed Apr 06, 2016 3:24 pm
Forum: Astro Pi
Topic: My Sense Hat Temp/Press/Hum Readings seem inaccurate
Replies: 4
Views: 3406

Re: My Sense Hat Temp/Press/Hum Readings seem inaccurate

The temperature of the sense hat will actually be consistently about 5 degrees high, by the experience of many people. See this link. https://www.raspberrypi.org/forums/viewtopic.php?f=104&t=111457&start=50 This seems to be due to radiant heat from the main pi processor. If the temperature is high, ...
by richrarobi
Wed Apr 06, 2016 12:14 pm
Forum: Beginners
Topic: Beginner needs some help please
Replies: 25
Views: 3832

Re: Beginner needs some help please

I know this is an old thread, but I think the need is still there (took me >4 days to stumble my way through the maze of documentation of mosquitto and json (while still adjusting to the coding idiosyncrasies of Python). So this might not be perfect:- Using two separate pi's and my big old linux ser...
by richrarobi
Wed Mar 30, 2016 9:28 pm
Forum: General discussion
Topic: Adafruit Servo HAT
Replies: 6
Views: 929

Re: Adafruit Servo HAT

You only need 4 wires to run the hat - sda, scl, 3v and grnd. The hat doesn't have to be used as a hat at all. put headers into the holes labelled sda,scl, 3v and grnd, and connect it by flying leads. Use pcb standoff supports as legs!! I use servo extension leads to connect to breadboard wires. I c...
by richrarobi
Wed Mar 30, 2016 8:28 pm
Forum: Advanced users
Topic: So many pis, so little desk space...
Replies: 13
Views: 2380

Re: So many pis, so little desk space...

I have to say that you really should look at the ssh approach. One system with a screen as master to all the others - put multiple screens on it if you wish! https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=11833&p=728951&hilit=pcmanfm#p728951 But how else are you going to take over the REST ...

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