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by davidcoton
Sat Feb 16, 2019 11:36 am
Forum: General discussion
Topic: apt -y upgrade stalls.
Replies: 6
Views: 74

Re: apt -y upgrade stalls.

apt (without -get) is intended for interactive operation. For unattended use, revert to apt-get. Then the "-y" option should (according to man) answer all prompts with "y". See "man apt-get" for more options, some of which might help.
by davidcoton
Sat Feb 16, 2019 11:26 am
Forum: Advanced users
Topic: Can not get RPI3B+ to boot from SD after program_gpio_bootmode=1
Replies: 7
Views: 132

Re: Can not get RPI3B+ to boot from SD after program_gpio_bootmode=1

The best guidance I can offer is DON'T DO THIS. It doesn't make enough difference to boot time. To elaborate a bit: even without programming and trying to use the GPIOs to control the boot process, a Pi3 (any variant) set up with no SDCard and with a compatible bootable USB MSD will boot from it, a...
by davidcoton
Sat Feb 16, 2019 11:13 am
Forum: Troubleshooting
Topic: The Big (little) Yellow Bolt of Doom
Replies: 16
Views: 286

Re: The Big (little) Yellow Bolt of Doom

. i found that if i bump the voltage up to 5.8 Volts on the PSU the power issues clear up and i get a reading of about 5.2 to 5.3 volts at the USB plug. Don't do that. When you shut down, the load (current) will decrease, so the voltage drop will decrease, so the voltage at the Pi will increase, an...
by davidcoton
Fri Feb 15, 2019 10:37 pm
Forum: Advanced users
Topic: Can not get RPI3B+ to boot from SD after program_gpio_bootmode=1
Replies: 7
Views: 132

Re: Can not get RPI3B+ to boot from SD after program_gpio_bootmode=1

GPIO22 disables SD1, GPIO23 disables SD2, GPIO24 disables NAND (irrelevant on a 3B+), GPIO25 disables SPI, and GPIO26 disables USB. Connect GPIO22 to 3V3 (pin#1 or pin#17) to disable SD boot. Or connect GPIO22 to GND to enable SD boot. Wrong way round, Dougie. https://www.raspberrypi.org/documentat...
by davidcoton
Fri Feb 15, 2019 2:11 pm
Forum: Troubleshooting
Topic: Updating bazel on Raspberry Pi 3
Replies: 7
Views: 89

Re: Updating bazel on Raspberry Pi 3

Of the releases listed in https://github.com/bazelbuild/bazel/releases ; none. They are all for x64 architecture, not ARM. Source code is available, so it could be compiled for ARM, and someone somewhere may have a compiled install package. Whether you compile it yourself is up to you, personally I ...
by davidcoton
Fri Feb 15, 2019 2:06 pm
Forum: Troubleshooting
Topic: The Big (little) Yellow Bolt of Doom
Replies: 16
Views: 286

Re: The Big (little) Yellow Bolt of Doom

(note the OS has nothing to do with it, the detection level is NOT programmable, but hard wired). Different OSs may not have been properly adapted for the correct GPIO assignment to control the undervolt warning on the Pi3B+. However, it does seem more likely that the PSU (a bench model that SHOULD...
by davidcoton
Fri Feb 15, 2019 10:56 am
Forum: Off topic discussion
Topic: Is ARM doomed?
Replies: 10
Views: 280

Re: Is ARM doomed?

Private Frazer wrote:We're all DOOMED.
All references to current British political (non-)events studiously avoided.
by davidcoton
Fri Feb 15, 2019 10:24 am
Forum: Beginners
Topic: Email pictures using Centurylink
Replies: 10
Views: 198

Re: Email pictures using Centurylink

pcmanbob wrote:
Fri Feb 15, 2019 10:14 am
I think you will find " smtplib " is for sending mail only.

If you want your pi to receive mail you will need to use anther method.
@pcmanbob, note the link to "poplib".

However, "imaplib" might be more futureproof. See the second paragraph of the link.
by davidcoton
Fri Feb 15, 2019 10:06 am
Forum: Beginners
Topic: Quick Question - Powering 7" Official Display/Case
Replies: 10
Views: 182

Re: Quick Question - Powering 7" Official Display/Case

It turns out my 64 GB SD card just wasn’t working for boot purposes. I believe the default format for 64GB (and larger) cards is not compatible with the Pi's boot loader. You need some extra magic incantation to format it correctly for NOOBS. No problem with Etcher, which writes a correctly formatt...
by davidcoton
Fri Feb 15, 2019 10:03 am
Forum: Beginners
Topic: New to raspberry - help with home automation
Replies: 1
Views: 58

Re: New to raspberry

You should probably start with Python, it's versatile and well supported. (Use Python3, not the older version -- both are installed in Raspbian by default.) I'm fairly sure there is a standard library for building a Web interface, but I haven't used it myself. More importantly, does your industrial ...
by davidcoton
Thu Feb 14, 2019 11:55 pm
Forum: Troubleshooting
Topic: The Big (little) Yellow Bolt of Doom
Replies: 16
Views: 286

Re: The Big (little) Yellow Bolt of Doom

Have you measured the voltage at the Pi's GPIO header 5V and Gnd pins? Be careful not to short anything (ideally use dupont wires) as doing so will kill the Pi.

What OS are you using?
by davidcoton
Thu Feb 14, 2019 10:59 pm
Forum: Beginners
Topic: Quick Question - Powering 7" Official Display/Case
Replies: 10
Views: 182

Re: Quick Question - Powering 7" Official Display/Case

Just to add my experience...I connected the Pi 3B+) to the display using only the jumper wires. Even with the official power supply (2.5 amp) I was seeing many lightning bolt under voltage warnings. Nothing else was connected to the Pi. Best to connect power to the Pi first, then via jumpers or USB...
by davidcoton
Thu Feb 14, 2019 10:55 pm
Forum: Beginners
Topic: How to install the OS on Raspberry Pi 3 Model B+
Replies: 28
Views: 439

Re: How to install the OS on Raspberry Pi 3 Model B+

I make a resume on what i will to do. Tell me, please, point by point if it s all correct. Yes. you wrote to use the .zip file. In one of the guide i posted above it's written to unzip the file and use the .img. What's the difference? Etcher can use an .img file, or the .zip version of the same. Si...
by davidcoton
Thu Feb 14, 2019 10:31 pm
Forum: General discussion
Topic: Communication with multiple arduinos
Replies: 2
Views: 70

Re: Communication with multiple arduinos

My question is when multiple arduino’s are sending how will it identify which board it came from? Is this done by sending the data with a unique iD or is there a better way? Which way is best efficient and scalable to handle this? Isn't that what the top level design of your system is all about? Is...
by davidcoton
Thu Feb 14, 2019 6:02 pm
Forum: Beginners
Topic: How to install the OS on Raspberry Pi 3 Model B+
Replies: 28
Views: 439

Re: How to install the OS on Raspberry Pi 3 Model B+

But before copying the .img with Etcher, do I need to follow this instructions ( https://www.raspberrypi.org/documentation/installation/installing-images/mac.md ) or i can ignore them? Ignore. The first paragraph of the section says Etcher is typically the easiest option for most users to write ima...
by davidcoton
Thu Feb 14, 2019 4:19 pm
Forum: Beginners
Topic: How to install the OS on Raspberry Pi 3 Model B+
Replies: 28
Views: 439

Re: How to install the OS on Raspberry Pi 3 Model B+

And the strong recommendation to use NOOBS could do with an addition along the lines of "unless you don't have a keyboard and monitor attached to your Pi" deletion FTFY. First timers may need help selecting the right Raspbian from the three versions, and ignoring the x86 image. I think it is now fi...
by davidcoton
Thu Feb 14, 2019 4:10 pm
Forum: Troubleshooting
Topic: Educational weather station issue - no module named gpizero.
Replies: 2
Views: 37

Re: Educational weather station issue - no module named gpizero.

The module is gpiozero I think. Check the spelling evry place it occurs in your program.
It helps to show us the whole of you code, use the [code]...[/code] tags in the message editor to display your code with the correct formatting.
by davidcoton
Thu Feb 14, 2019 9:40 am
Forum: General discussion
Topic: Powering RPi inside of PC case
Replies: 17
Views: 776

Re: Powering RPi inside of PC case

re power i tend to run 5v and ground into the gpio connector using a 10-pin header at pos-1 . for simple projects this gets me i2c and tx/rx which i've used for rtc and tmp107 temperature probes. As always, be aware that powering through the GPIO header bypasses the power protection circuitry. Ther...
by davidcoton
Wed Feb 13, 2019 5:59 pm
Forum: Beginners
Topic: A basic setup that randomly turns on a light for a random time.
Replies: 8
Views: 138

Re: A basic setup that randomly turns on a light for a random time.

Whatever you try, you need to be aware of electrical safety if you are switching mains. If you do not have specific knowledge of your local regulations, and the experience to implement them, avoid working with mains. For example, many relay boards capable of switching mains are not safe, because mai...
by davidcoton
Wed Feb 13, 2019 3:05 pm
Forum: Beginners
Topic: Power Supply for multiple 12V devices
Replies: 5
Views: 85

Re: Power Supply for multiple 12V devices

Without drawing a big circuit diagram (which I should and most-likely will do), I will basically have MOSFETs (RFP30N06LE 30A 60V N-Channels) for each solenoid..let's say 8 solenoids, gates controlled by the Pi. Each will require 2 GPIO pins (one to toggle the gate for ON mode and two to send a pin...
by davidcoton
Tue Feb 12, 2019 11:12 pm
Forum: Beginners
Topic: Power Supply for multiple 12V devices
Replies: 5
Views: 85

Re: Power Supply for multiple 12V devices

From what you have said, yes it is that easy.
by davidcoton
Mon Feb 11, 2019 11:58 pm
Forum: Troubleshooting
Topic: Do we have a way to invert the logic of the GPIO serial port?
Replies: 13
Views: 281

Re: Do we have a way to invert the logic of the GPIO serial port?

Check the voltages in use too. The GPIO will not tolerate 5V TTL. Proper RS232 is +/- between 3V and 24V, "poorman RS232" is non-standard, I suspect.
by davidcoton
Mon Feb 11, 2019 5:58 pm
Forum: General programming discussion
Topic: Controlling 100 LED's over TCP/IP between two Pi's
Replies: 8
Views: 181

Re: Controlling 100 LED's over TCP/IP between two Pi's

Doesn't Joan's GPIO library allow remote access to GPIO on another Pi?

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