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by Paul Hutch
Fri Apr 12, 2019 6:08 pm
Forum: General discussion
Topic: GIVE YOUR RASPBERRY PI SD CARD A BREAK: LOG TO RAM
Replies: 19
Views: 2568

Re: GIVE YOUR RASPBERRY PI SD CARD A BREAK: LOG TO RAM

Excellent license choice, well known, OSI approved, and legally tested, thanks for adding it. I'll be trying your scripts to use in a work project early next week.
by Paul Hutch
Wed Apr 10, 2019 3:32 pm
Forum: Advanced users
Topic: Changing boot order or stopping programs from loading
Replies: 2
Views: 199

Re: Changing boot order or stopping programs from loading

Just tried the raspi-config option and at least on the latest Raspbian Lite, it does not wait for what most people consider a valid network connection. It allows boot to complete even if there is no LAN connection via eth0 and wlan0 due to unplugged cable and no valid SSID/key pair.
by Paul Hutch
Wed Apr 10, 2019 2:45 pm
Forum: General discussion
Topic: GIVE YOUR RASPBERRY PI SD CARD A BREAK: LOG TO RAM
Replies: 19
Views: 2568

Re: GIVE YOUR RASPBERRY PI SD CARD A BREAK: LOG TO RAM

I suggest you have a look at https://github.com/StuartIanNaylor/zram-config <snip> Looking to build a community around https://github.com/StuartIanNaylor/zram-config so any ideas or issues please post away and get involved as claim no ownership just annoyed me so many utils for this application are...
by Paul Hutch
Wed Apr 10, 2019 1:24 pm
Forum: Python
Topic: How to check to see if a process is running via subprocess, and not do it if it already exists.
Replies: 4
Views: 259

Re: How to check to see if a process is running via subprocess, and not do it if it already exists.

subprocess.Popen has a built-in method to determine if the subprocess is still running, Popen.poll().

In your code process.Popen.poll() will return the state of the process.

https://docs.python.org/3/library/subpr ... en-objects
by Paul Hutch
Wed Apr 10, 2019 1:05 pm
Forum: Advanced users
Topic: Pi 3 b+ power supply issue
Replies: 13
Views: 1005

Re: Pi 3 b+ power supply issue

I already check on the data sheets. The GNSS/GPS/GSM HAT requires 5Volt (operating voltage) in addition the 7 inch display is connected directly to raspberry pi's usb port. The last one, IMU sensor, is connected to the GPIO header (3.3V pin e uart pins). You also need to look for the current requir...
by Paul Hutch
Wed Apr 10, 2019 11:42 am
Forum: Advanced users
Topic: WiFi Connection manager with fallback web configuration portal
Replies: 7
Views: 462

Re: WiFi Connection manager with fallback web configuration portal

Thank you very much dividuum, that looks like a good solution for many users.
by Paul Hutch
Mon Apr 08, 2019 3:20 pm
Forum: General discussion
Topic: Raspberry Pi 2 RS232 Wireless transmitter
Replies: 2
Views: 222

Re: Raspberry Pi 2 RS232 Wireless transmitter

I've used devices similar to this one in the past.
http://www.nordfield.com/wireless-seria ... th-adapter
by Paul Hutch
Thu Apr 04, 2019 6:26 pm
Forum: Weather station
Topic: Temps are off by about 10 degrees (F)
Replies: 11
Views: 5352

Re: Temps are off by about 10 degrees (F)

A 5°F difference between roof level and ground level is not uncommon even with no direct sun on the sensor, with sun I've measured 15°F differences. The air up high is just not the same temperature as the air at the normal air temperature measurement height of ~1.5m. https://www.weatherworksinc.com/...
by Paul Hutch
Wed Apr 03, 2019 2:51 pm
Forum: Advanced users
Topic: Voltage reduction under thermal throttling
Replies: 7
Views: 412

Re: Voltage reduction under thermal throttling

There are three voltage/frequency setpoints for the 3B+ <snipped excellent information> Thank you for the info, one of the best things about this forum is how many RasPi engineers come to help us all out, keep up the good work. A big thanks to all of you, the rest of the RasPi staff, volunteer mode...
by Paul Hutch
Wed Apr 03, 2019 2:43 pm
Forum: General discussion
Topic: 3.3v Relay Exists?
Replies: 7
Views: 445

Re: 3.3v Relay Exists?

This not suited for your requirements? https://uk.rs-online.com/web/p/non-latching-relays/6839258/ Unfortunately that particular unit, and every traditional coil based 3V relay I've encountered, requires too much current for direct drive from the 3.3V GPIO of a Raspberry Pi. The linked relay has a ...
by Paul Hutch
Tue Apr 02, 2019 6:09 pm
Forum: Advanced users
Topic: Voltage reduction under thermal throttling
Replies: 7
Views: 412

Re: Voltage reduction under thermal throttling

I ran some some stress tests with a RasPi 3B+ with no heatsink and a sealed case, in an oven at 65°C ambient earlier this year to see how hot I could make it. I ran out of time and wasn't able to push it as far as I wanted but I did get it to throttle down to 600 MHz and the lowest I saw for a core ...
by Paul Hutch
Tue Apr 02, 2019 5:55 pm
Forum: Advanced users
Topic: WiFi Connection manager with fallback web configuration portal
Replies: 7
Views: 462

Re: WiFi Connection manager with fallback web configuration portal

From what I've read nobody who has coded this type of system for the Raspberry Pi has released it as free software. Later this year I'll be working on this functionality for a work project and I intend it to be FLOSS, but do to work time constraints I'm certain I won't be able to get the project set...
by Paul Hutch
Fri Mar 29, 2019 10:42 am
Forum: General discussion
Topic: Measuring Pi power with a Keweisi USB tester
Replies: 3
Views: 159

Re: Measuring Pi power with a Keweisi USB tester

Assuming that the phone charging is at a much higher current than 100mA, the Keweisi USB tester may not be accurate at lower current values. Large variation in accuracy over the measurement range is a common accuracy problem of low cost measurement devices.
by Paul Hutch
Fri Mar 29, 2019 12:04 am
Forum: General discussion
Topic: Email alert images accumulating on sd card
Replies: 17
Views: 692

Re: Email alert images accumulating on sd card

Dubman wrote:
Thu Mar 28, 2019 8:53 am
Paul, do you mean just making the following change to this script? (See: #Delete this line)
Yes, that should make it send just a regular email and if those stay as separate emails then we can be sure it's an attachment handling issue.
by Paul Hutch
Wed Mar 27, 2019 10:59 pm
Forum: General discussion
Topic: Email alert images accumulating on sd card
Replies: 17
Views: 692

Re: Email alert images accumulating on sd card

I have a RasPi0W monitoring the dehumidifier in my basement, it emails me when it needs to be emptied and sends a status email every day at midnight UTC. I haven't had a full email since the beginning of January, winter is dry here, but I do get the daily emails. There are whole bunch of the daily e...
by Paul Hutch
Wed Mar 20, 2019 10:58 pm
Forum: Advanced users
Topic: Why is or are PCF857x IO expansion modules always low trigger for output?
Replies: 2
Views: 136

Re: Why is or are PCF857x IO expansion modules always low trigger for output?

It's because that IC uses quasi-bidirectional I/O ports which are less expensive to implement in silicon than true bidirectional I/O ports.
by Paul Hutch
Wed Mar 20, 2019 10:40 pm
Forum: General discussion
Topic: python email alert images accumulating
Replies: 4
Views: 252

Re: python email alert images accumulating

Ah, I guess the "server.quit()" doesn't actually quit the server when called (multi-threading issue) so the clearing of the "msg" email content variable is happening before the email has been sent. So my next guess is that doing the clearing of the old email content needs to be moved to just before ...
by Paul Hutch
Tue Mar 19, 2019 11:00 pm
Forum: General discussion
Topic: python email alert images accumulating
Replies: 4
Views: 252

Re: python email alert images accumulating

I've never worked with attachments but I'd try clearing the variable after sending.

Code: Select all

        server.send_message(msg)
        server.quit()
	msg = None
by Paul Hutch
Sat Feb 23, 2019 2:54 pm
Forum: General discussion
Topic: Pi 3 b+ disturbing our Motorola comradios for firefighting.
Replies: 6
Views: 622

Re: Pi 3 b+ disturbing our Motorola comradios for firefighting.

Assuming the radios are on a reserved or licensed frequency band then it seems unlikley the Pi itself is the main culprit, it is more likely peripheral circuitry. To test this run the Pi with nothing but a power connection. If as I suspect there is no interference signal then start adding back perip...
by Paul Hutch
Thu Feb 14, 2019 5:30 pm
Forum: General discussion
Topic: Weather station in freezing weather: questions
Replies: 17
Views: 735

Re: Weather station in freezing wheather: questions

At this point, I think it's reasonable to think that any random Pi will *probably* function in moderate below freezing temperatures...and if a given Pi doens't, the next one will. It's just as reasonable to think that any given Pi will *probably* NOT work reliably below freezing. So it's a gamble, ...
by Paul Hutch
Thu Feb 14, 2019 11:39 am
Forum: General discussion
Topic: Weather station in freezing weather: questions
Replies: 17
Views: 735

Re: Weather station in freezing wheather: questions

Can't help you the instruments, but you needn't worry about the Pi itself. A researcher at CERN managed to make one fail by getting too cold. It quit working at -180C. I had my one outdoor mounted RasPi quit working at around -20°C. Single piece experiences are merely anecdotes, without a spec from...
by Paul Hutch
Mon Feb 11, 2019 3:28 pm
Forum: General discussion
Topic: Is Raspberry Pi capable of replacing 2 wire thermostat
Replies: 8
Views: 545

Re: Is Raspberry Pi capable of replacing 2 wire thermostat

This is one of those projects that will take far more time and cost far more money than any plan will estimate. Plus it may cause grief if bugs in your custom system leave the heat off and you get real cold, leave it on wasting oil, or off while your away and the house pipes freeze and your insuranc...
by Paul Hutch
Fri Feb 01, 2019 11:39 am
Forum: Android
Topic: [android] DHCP Client not assigning the Auto IP
Replies: 6
Views: 1636

Re: DHCP Client not assigning the Auto IP

You'll probably get more help if you ask in the Android sub-forum.
https://www.raspberrypi.org/forums/viewforum.php?f=73
by Paul Hutch
Thu Jan 31, 2019 2:07 am
Forum: General discussion
Topic: Using the Raspberry Pi logo
Replies: 20
Views: 1211

Re: Using the Raspberry Pi logo

jamesh, Why should the owners of the trademark, on their own webpage, have to put a (R) on it? That is a very good question and one that has been puzzling me for some time. Even Intel does it, for example: 9th Gen Intel® Core™ S-series processors brief From Intel's web page here: https://www.intel....
by Paul Hutch
Wed Jan 30, 2019 4:52 pm
Forum: General discussion
Topic: Using the Raspberry Pi logo
Replies: 20
Views: 1211

Re: Using the Raspberry Pi logo

"You may only use the Raspberry Pi Logo in connection with the sale or distribution of genuine Raspberry Pi products or services." Which means I technically cannot use the logo in an intro. Looking at the visual rules, I see that it says that your not allowed to remove the trademark from the logo. ...

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