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by pfletch101
Fri May 04, 2018 2:24 pm
Forum: Advanced users
Topic: Life of Pi? Is 24/7 use better than on-off switching?
Replies: 14
Views: 2936

Re: Life of Pi? Is 24/7 use better than on-off switching?

One would have to sit down with actual figures to work out whether more current were drawn through power-cycling than leaving it on. My personal gut feeling is sustained power consumption could easily exceed any brief current surges caused through power cycling. Given the OP's detailed explanation ...
by pfletch101
Thu May 03, 2018 3:07 pm
Forum: Advanced users
Topic: Life of Pi? Is 24/7 use better than on-off switching?
Replies: 14
Views: 2936

Re: Life of Pi? Is 24/7 use better than on-off switching?

'Received wisdom' (without a great deal of hard evidence that I know of) is that repeated power on/off cycling is more likely to lead to problems with electronic equipment that leaving it on 24/7, provided that cooling is adequate to keep the equipment well within its normal operating temperature ra...
by pfletch101
Wed May 02, 2018 2:00 pm
Forum: Python
Topic: Python script fail @reboot
Replies: 6
Views: 1828

Re: Python script fail @reboot

I am also facing the same problem. Code runs fine from interpreter but during reboot it shows error in importing a library - import gtts saying that "ImportError : No module named gtts". I tried using time.sleep(100) , but to no help! The importing of library doesn't even require internet...
by pfletch101
Wed May 02, 2018 12:51 am
Forum: Beginners
Topic: Trying to translate a c program to arm assembler
Replies: 10
Views: 2057

Re: Trying to translate a c program to arm assembler

It is more years than I like to remember since I programmed in assembly language (for everything from the Apple II, through DEC minis, to the earlier members of the 8088 series), but I think that, if you really want to understand what you are doing, you have to start from the ground up. Start by lea...
by pfletch101
Wed May 02, 2018 12:40 am
Forum: Beginners
Topic: copying files
Replies: 2
Views: 1837

Re: copying files

You can do most things that need special privileges (including copying files to protected folders) from the pi user prompt by preceding the command with 'sudo', e.g.:

Code: Select all

sudo cp myfile /etc
by pfletch101
Tue May 01, 2018 7:53 pm
Forum: Networking and servers
Topic: Configuring connections to MyCloud Mirror NAS server
Replies: 0
Views: 391

Configuring connections to MyCloud Mirror NAS server

I set up a connection to my WD MyCloud NAS device from one of my Pi 3Bs yesterday after enabling SSH on the MyCloud and creating an appropriate Share on it, and otherwise following the guidance in https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=172182 for the Pi end. It works fine, and I...
by pfletch101
Sun Apr 29, 2018 3:18 pm
Forum: Beginners
Topic: How to read solar panel input and battery output
Replies: 5
Views: 3436

Re: How to read solar panel input and battery output

Your setup looks quite similar to that of the OP in the thread I linked to, and there is a lot of relevant information there. Essentially you need insert/attach voltage and current sensors in a number of locations in your circuit, use an Analog to Digital Converter (ADC) chip to feed the sensors' re...
by pfletch101
Sat Apr 28, 2018 3:37 am
Forum: Beginners
Topic: Capturing audio - is there anything that works?
Replies: 4
Views: 839

Re: Capturing audio - is there anything that works?

Looks like a faulty installation, with some files either missing or not where the program expects to find them. Unfortunately, I don't know this particular application so I can't be of more help.
by pfletch101
Sat Apr 28, 2018 1:17 am
Forum: Python
Topic: Installing Program requiring Python 2.7 when default is 3.x
Replies: 17
Views: 8596

Re: Installing Program requiring Python 2.7 when default is 3.x

Weewx may not be the only application that depends on Python 2 as default. If you want to keep system compatibility then IMO change the default back to python 2 and use python3 to start Python 3 code and either python or python 2 to start Python 2 code...... and when Python 4 comes out use python4 ...
by pfletch101
Sat Apr 28, 2018 12:08 am
Forum: Python
Topic: Installing Program requiring Python 2.7 when default is 3.x
Replies: 17
Views: 8596

Re: Installing Program requiring Python 2.7 when default is 3.x

I have both (2.x and 3.x) versions of Python installed on my Pi 3B+, but I have it set up to default to 3.x. I want to install Weewx, which requires 2.7, and I know that the install will work if I temporarily make the older version the default, but I suspect that if I subsequently set the default b...
by pfletch101
Sat Apr 28, 2018 12:04 am
Forum: Python
Topic: Installing Program requiring Python 2.7 when default is 3.x
Replies: 17
Views: 8596

Re: Installing Program requiring Python 2.7 when default is 3.x

DougieLawson wrote:
Fri Apr 27, 2018 10:39 pm
Python 2.7 is still the default in Raspbian Stretch. You have to jump through a small hoop to run python3.
As I noted, I have set my installation up to default to Python 3.x.
by pfletch101
Fri Apr 27, 2018 10:35 pm
Forum: Python
Topic: Installing Program requiring Python 2.7 when default is 3.x
Replies: 17
Views: 8596

Installing Program requiring Python 2.7 when default is 3.x

I have both (2.x and 3.x) versions of Python installed on my Pi 3B+, but I have it set up to default to 3.x. I want to install Weewx, which requires 2.7, and I know that the install will work if I temporarily make the older version the default, but I suspect that if I subsequently set the default ba...
by pfletch101
Fri Apr 27, 2018 7:17 pm
Forum: Beginners
Topic: How to read solar panel input and battery output
Replies: 5
Views: 3436

Re: How to read solar panel input and battery output

You don't give a lot of detail of the setup you want to monitor. In particular, you don't say whether the system is all DC or includes inverters, so that your batteries and solar array are ultimately supplying AC power to your load(s). It is (relatively) easy to measure AC current and power without ...
by pfletch101
Fri Apr 27, 2018 3:16 pm
Forum: Beginners
Topic: Capturing audio - is there anything that works?
Replies: 4
Views: 839

Re: Capturing audio - is there anything that works?

If this is a power issue, you should be seeing flashing or other disturbances of the power light on the Pi board. If you can't normally see this, it would be worth checking it while running your software, before looking for other causes.
by pfletch101
Wed Apr 25, 2018 9:40 pm
Forum: Advanced users
Topic: Mean of 60 temperature sensors
Replies: 17
Views: 2914

Re: Mean of 60 temperature sensors

I suspect that the OP's question may have more to do with gathering the data than with the trivial problem of calculating the mean of 3*60 values! I can't immediately think of a (wired or wireless) approach that would be likely to work without using a fair number of Pis as data collection hubs. Does...
by pfletch101
Wed Apr 25, 2018 6:08 pm
Forum: Beginners
Topic: Ipad to TV through RPi (Ipad-wifi-Rpi-HDMI-TV)
Replies: 17
Views: 13580

Re: Ipad to TV through RPi (Ipad-wifi-Rpi-HDMI-TV)

Another approach would be to use the Pi to stream Netflix and YouTube videos directly. It can't handle Netflix natively, but here again Google ("rasp pi Netflix") is your friend!
by pfletch101
Wed Apr 25, 2018 3:37 pm
Forum: Beginners
Topic: Ipad to TV through RPi (Ipad-wifi-Rpi-HDMI-TV)
Replies: 17
Views: 13580

Re: Ipad to TV through RPi (Ipad-wifi-Rpi-HDMI-TV)

How feasible this will be depends on exactly what you want to display. Duplicating the iPad's screen on a TV, irrespective of what it is doing, is likely to be non-trivial, but there appear to be a lot of working approaches to duplicating the function of Google's Chromecast device (which allows more...
by pfletch101
Wed Apr 25, 2018 12:53 am
Forum: Beginners
Topic: Raspberry Pi audio distribution amplifier
Replies: 1
Views: 275

Re: Raspberry Pi audio distribution amplifier

The short answer to your question is 'No'. Computers can only handle analog signals (which is what audio signals are) by converting them to digital formats first, processing them in digital form, and then converting them back to analog form. Although the audio output of your laptop is obviously prod...
by pfletch101
Sun Apr 22, 2018 3:02 pm
Forum: Beginners
Topic: Memtester?
Replies: 8
Views: 3662

Re: Memtester?

I am less familiar with the details of power draws in the Pi world than I am in the world of desktop computers, but the power draws when you do see signs of your power supply being inadequate seem likely to be higher than I would expect even with the CPU transiently maxed out, but no other devices d...
by pfletch101
Sat Apr 21, 2018 8:46 pm
Forum: Beginners
Topic: Memtester?
Replies: 8
Views: 3662

Re: Memtester?

But just to be clear, it is or isn't normal for web pages to freeze and crash chromium as soon as they are opened or a little movement or scrolling is done on the page? I load and use some very resource intensive web pages regularly, and have never seen this - they just load much slower than they d...
by pfletch101
Sat Apr 21, 2018 2:04 pm
Forum: Beginners
Topic: Power Supply recommendations wanted
Replies: 7
Views: 958

Re: Power Supply recommendations wanted

Thanks to all! I have ordered a couple (in case one of my other 'kit' supplies also fails).
by pfletch101
Fri Apr 20, 2018 11:18 pm
Forum: Beginners
Topic: Power Supply recommendations wanted
Replies: 7
Views: 958

Power Supply recommendations wanted

Has anyone got any (positive or negative) thoughts on particular makes/types of power supplies for Pi 3s, run under reasonably light working conditions. One 2.5A power supply which I bought with a kit only a month ago seems to be on its way out (power LED flashing and even going off under relatively...
by pfletch101
Fri Apr 20, 2018 3:02 pm
Forum: Beginners
Topic: General approach saving sensor data to database at interval
Replies: 6
Views: 4742

Re: General approach saving sensor data to database at interval

I learned not to have a Python program running all the time, use cron to call it and then exit it. What did you learn about having a Python program running all the time that led you to stop doing that? Save up a day and then write to file on card, it saves wear on the card. You might lose a day of ...
by pfletch101
Thu Apr 19, 2018 1:11 am
Forum: Beginners
Topic: Sharing sensor data
Replies: 17
Views: 3185

Re: Sharing sensor data

Shadow_Saunter wrote:
Wed Apr 18, 2018 6:35 pm
pfletch101 wrote: ...A separate application on the Pi serves the data to the main program, which runs on a Windows desktop.
What is the separate application?
It is a custom TCP server, written in Python. A dedicated TCP client within the desktop application (which is written in VB.Net) communicates with it.
by pfletch101
Tue Apr 17, 2018 7:47 pm
Forum: Beginners
Topic: Sharing sensor data
Replies: 17
Views: 3185

Re: Sharing sensor data

MariaDB is a great database application, but it may be overkill for something like this. I use SQLite to store the data from my sensors for my whole-house energy control and monitoring program. A separate application on the Pi serves the data to the main program, which runs on a Windows desktop.

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