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by Paul Hutch
Tue Apr 02, 2019 6:09 pm
Forum: Advanced users
Topic: Voltage reduction under thermal throttling
Replies: 7
Views: 493

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: 556

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: 203

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: 804

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: 804

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: 165

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: 301

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: 301

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: 676

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: 18
Views: 914

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: 18
Views: 914

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: 640

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: 1822

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: 1443

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: 1443

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. ...
by Paul Hutch
Wed Jan 30, 2019 4:28 pm
Forum: General discussion
Topic: I'm trying to design a timing system for an engine
Replies: 1
Views: 153

Re: I'm trying to design a timing system for an engine

I'm assuming you mean a system for ignition timing of an internal combustion engine for real world usage. If it's a model engine, steam engine, etc. then ignore what follows. IMO, a Rapspberry Pi, or any Linux compatible SBC, is possibly the worst choice for an engine timing system. An Arduino would...
by Paul Hutch
Sat Jan 26, 2019 3:32 pm
Forum: General discussion
Topic: Recommend a decent power supply
Replies: 9
Views: 673

Re: Recommend a decent power supply

Imperf3kt wrote:
Sat Jan 26, 2019 12:49 pm
Why not use the official power supply plus a short, say 1.5m, extension cable?
The extra connectors and double the wire length may very well cause too much voltage drop. A better option is to cut out the original wire and solder splice in a larger gauge wire 3m long.
by Paul Hutch
Tue Jan 22, 2019 4:36 pm
Forum: Advanced users
Topic: Accurate timing for real time control
Replies: 30
Views: 54716

Re: Accurate timing for real time control

Hi There - need some advice. I want to read an analog-to-digital input from the ADS1015 ADC, via I2C bus. The data will be a graph, clocked at about 3Khz. This link suggests using the AnalogIn function to read the analog channel. https://learn.adafruit.com/adafruit-4-channel-adc-breakouts/python-ci...
by Paul Hutch
Mon Jan 21, 2019 2:45 pm
Forum: Advanced users
Topic: GPIO-POWEROFF: Is it safe to immediately cut power off when pin goes LOW?
Replies: 3
Views: 561

Re: GPIO-POWEROFF: Is it safe to immediately cut power off when pin goes LOW?

I can only see about 3-4 blinks of the ACT LED when issuing sudo shutdown -h now but if I shutdown without using the GPIO-POWEROFF the ACT LED certainly blinks more about 10 flashes. I was trying out the gpio-poweroff overlay this weekend and I saw the same thing. When I use the overlay, instead of...
by Paul Hutch
Fri Jan 11, 2019 11:32 am
Forum: General discussion
Topic: Geany Error
Replies: 9
Views: 550

Re: Geany Error

Update - I used a new SD card with a fresh copy of Stretch - Geany ran perfectly with all the programs I have been developing in Python, ran them all repeatedly with no errors and no crashing. Put back the SD card with the crashing Geany, and Geany will only run once, irrespective of whatever pytho...
by Paul Hutch
Tue Jan 08, 2019 12:50 am
Forum: General discussion
Topic: Heatsink required for Raspberry Pi 3 B+?
Replies: 59
Views: 51931

Re: Heatsink required for Raspberry Pi 3 B+?

From what I've been told here on the forum a Raspberry Pi will not stop from overheating, therefore something other that overheating is causing it to stop completely.
by Paul Hutch
Sat Dec 29, 2018 2:33 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: Raspberry Pi Desktop on a 64-bit VirtualBox VM
Replies: 8
Views: 7125

Re: Raspberry Pi Desktop on a 64-bit VirtualBox VM

Hello People, I have been struggling to get this project off the ground since 24/12/18. It is now 27/12/17 and I hope I have stumbled upon an answer. Perhaps it is DO NOT USE 64 Bit Use 32 Bit, I really hope so. I have successfully (up to a point) got Raspberry Pi working inside the VirtualBox on m...
by Paul Hutch
Sat Dec 22, 2018 7:03 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: Can't Install Geany
Replies: 13
Views: 1610

Re: Can't Install Geany

Thanks for all the replies. It's good to confirm it's not just me screwing up there is a little distro version glitch, and great to get info on ways to work around the issue.
by Paul Hutch
Sat Dec 22, 2018 12:36 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: Can't Install Geany
Replies: 13
Views: 1610

Re: Can't Install Geany

code_exec wrote:
Sat Dec 22, 2018 5:26 am
I advise you to run sudo apt update to update the package lists and then try again.
That was tried multiple times before making the OP.
by Paul Hutch
Tue Dec 18, 2018 1:53 pm
Forum: General discussion
Topic: Extending power supply cable using Cat6 pair
Replies: 8
Views: 523

Re: Extending power supply cable using Cat6 pair

To figure out the voltage drop you can use this spreadsheet. https://docs.google.com/spreadsheets/d/1_Z_ef7yN4aqKFH5u5rLQuIe44sPckPo6ikrf9Xva41o/edit?usp=sharing To see how much current it takes to fuse (melt) wires see this chart. https://www.powerstream.com/wire-fusing-currents.htm ETA 12/19 - For...

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