Go to advanced search

by davidcoton
Fri Jul 19, 2019 11:53 pm
Forum: Troubleshooting
Topic: Low Power warning on Pi3B+ with 5v10A supply? sw hook for low power?
Replies: 4
Views: 82

Re: Low Power warning on Pi3B+ with 5v10A supply? sw hook for low power?

Have you measured the voltage at the Pi? It seems from your description that you are losing voltage on the supply cable What size are the power wires? You may be able to tell from the cable marking, something like "28AWG/1P+28AWG/2C" says one data pair of 28AWG (irrelevant) and 2 cores of 28AWG for ...
by davidcoton
Fri Jul 19, 2019 10:59 pm
Forum: Beginners
Topic: 3B+ just stopped working?!
Replies: 1
Views: 51

Re: 3B+ just stopped working?!

If you've tried another SDCard, preferably one that works in another Pi of the same model or newer, then it's not likely that the SDCard is the problem. You can test for 3V3 between pins 1 and 6 of the GPIO header (see https://pinout.xyz/# ). Use jumper wires and avoid shorting any pins -- doing so ...
by davidcoton
Thu Jul 18, 2019 10:02 pm
Forum: General discussion
Topic: gpio/switch + python
Replies: 6
Views: 127

Re: gpio/switch + python

you like the code without the "GPIO.HIGH"?? My personal preference is "GPIO.HIGH" rather than "1". It's more expressive, though in this context it's clear either way. In a strongly typed language (modern versions of C++) "1" would give a compiler warning, because it could be a mistake. In other con...
by davidcoton
Wed Jul 17, 2019 11:25 pm
Forum: Beginners
Topic: Best manners with the breadboarding ??
Replies: 9
Views: 219

Re: Best manners with the breadboarding ??

  1. Possible but unlikely. Avoid very dry conditions and nylon carpets and clothes.
  2. Do not move wires without shutting down and disconnecting power.
  3. No.
  4. Yes.
by davidcoton
Wed Jul 17, 2019 11:17 pm
Forum: Beginners
Topic: Is it possible to have Acess Point and Wifi at the same time?
Replies: 7
Views: 336

Re: Is it possible to have Acess Point and Wifi at the same time?

Also would want SMA or u.FL connector for external antenna. That would invalidate the Pi's UK, EU and USA approvals. It can result in unfriendly visits from the men in black. If adapter is connected via USB and has an option of an external antenna then as long as the antenna is approved for that de...
by davidcoton
Wed Jul 17, 2019 9:17 pm
Forum: Beginners
Topic: Is it possible to have Acess Point and Wifi at the same time?
Replies: 7
Views: 336

Re: Is it possible to have Acess Point and Wifi at the same time?

Also would want SMA or u.FL connector for external antenna. That would invalidate the Pi's UK, EU and USA approvals. It can result in unfriendly visits from the men in black. EDIT: Sorry, socketed aerial on an external adapter (if designed that way) is OK. It is modification of the Pi that causes a...
by davidcoton
Tue Jul 16, 2019 7:33 pm
Forum: Troubleshooting
Topic: [Solved] New Raspberry 4b 4g dead upon arrival
Replies: 17
Views: 705

Re: New Raspberry 4b 4g dead upon arrival

That did it. I interpreted the line on this site saying "and as always, we've kept all our software backwards-compatible" to mean that current configurations (e.g. Stretch) would work. Apparently not. In any case, thank you for your help! "Backwards"-compatible is the other way round -- new softwar...
by davidcoton
Tue Jul 16, 2019 5:32 pm
Forum: Troubleshooting
Topic: [Solved] New Raspberry 4b 4g dead upon arrival
Replies: 17
Views: 705

Re: New Raspberry 4b 4g dead upon arrival

Soup64 wrote:
Tue Jul 16, 2019 4:50 pm
I've tried known good SDcards that boot just fine with my 3B+.
Which OS? The Pi4B requires a new version -- try downloading the latest Raspbian Buster, write it to an SDCard with Etcher, and see if that boots.
by davidcoton
Tue Jul 16, 2019 11:11 am
Forum: General discussion
Topic: I didn't think the usb c power thing was a big deal...
Replies: 92
Views: 4006

Re: I didn't think the usb c power thing was a big deal...

Some may have access to more expensive stuff then they own themselves though. E.g. kid that bought his own Pi, but planned to borrow the charger of dad's (or mom's) Macbook. And that Macbook may actually not even be owned by the parent, but provided by their employer. Possible, yes. But employers t...
by davidcoton
Tue Jul 16, 2019 9:05 am
Forum: Troubleshooting
Topic: raspberry pi 4 rebooting
Replies: 2
Views: 97

Re: raspberry pi 4 rebooting

What are you using as a power supply?
by davidcoton
Tue Jul 16, 2019 9:02 am
Forum: General discussion
Topic: Raspberrypi 4 compute module release date
Replies: 6
Views: 255

Re: Raspberrypi 4 compute module release date

slow performance, obscurity (language and coding), inflexibility (macro assignment and date format). Forth, built for 6502 running under an emulator based on CP/M under Z80 emulator on a x86 emulator on a Pi linked to ctrl-alt-del in English text based on number of days after the first Easter of th...
by davidcoton
Tue Jul 16, 2019 8:56 am
Forum: Beginners
Topic: Do I HAVE to use LibreOffice?
Replies: 14
Views: 595

Re: Do I HAVE to use LibreOffice?

You don't HAVE to use anything on your Pi, but by turning down LibreOffice you reject the most cost-effective Office package available. I've been using it for over ten years, replacing MSOffice completely (it will now read any MS format I throw at it). I use it on Windoze and Ubuntu. I use Writer (i...
by davidcoton
Tue Jul 16, 2019 8:34 am
Forum: General discussion
Topic: When are people in the U.S. getting their Pi 4s?
Replies: 108
Views: 3998

Re: When are people in the U.S. getting their Pi 4s?

travisfarmer wrote:
Tue Jul 16, 2019 8:22 am
it was ordered June 1st.
How did you know about the Pi4B a month before it was announced?
by davidcoton
Tue Jul 16, 2019 8:32 am
Forum: General discussion
Topic: Raspberrypi 4 compute module release date
Replies: 6
Views: 255

Re: Raspberrypi 4 compute module release date

Odd, I though this was scheduled for a day with a ‘y’ in the name... Wonder if the folk have a macro key set up for these? Two further predictions: The English month name will not contain "z" or "q" The year number will contain the digit "2" Challenge: write a shell script or a program in your favo...
by davidcoton
Tue Jul 16, 2019 8:23 am
Forum: General discussion
Topic: I didn't think the usb c power thing was a big deal...
Replies: 92
Views: 4006

Re: I didn't think the usb c power thing was a big deal...

There are people here which can hardly afford to buy a Pi. Is that because they've spent their money on overpriced premium computer systems? Those on a budget probably don't have the expensive (currently incompatible) e-marked cables in the first place. Anyone who can afford e-marked cables and the...
by davidcoton
Tue Jul 16, 2019 8:18 am
Forum: Off topic discussion
Topic: Suggestion for future models
Replies: 3
Views: 338

Re: Suggestion for future models

sandwiches on wheels. A self-driving sandwich van :?: :lol: :ugeek: With a Pi in control :!: :o :shock: If the Pi layout has to change, then matching SSD mountings would be a good way to go, assuming the other considerations that force the change can be satisfied. Since this change won't happen unl...
by davidcoton
Mon Jul 15, 2019 9:34 pm
Forum: General discussion
Topic: I didn't think the usb c power thing was a big deal...
Replies: 92
Views: 4006

Re: I didn't think the usb c power thing was a big deal...

jamesh wrote:
Mon Jul 15, 2019 9:29 pm
Here's an independent site talking about the USB_C issue, and how much of a problem it isn't.

https://www.raspberrypi.org/forums/view ... 1500305tml
Wrong link?
by davidcoton
Mon Jul 15, 2019 4:52 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: Error during booting (installing)
Replies: 9
Views: 313

Re: Error

Feramano wrote:
Mon Jul 15, 2019 4:00 pm
Does anyone has ever have this problem? I need help because im completely lost. https://ibb.co/qmrxP0b
I for one will not follow a random obfuscated link from a first-time poster.
Please give more details in your post. Use imgur or similar for photos, if necessary.
by davidcoton
Mon Jul 15, 2019 4:43 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 30
Views: 966

Re: Want to measure battery volts

https://www.aliexpress.com/item/32914076246.html?storeId=1773456&spm=2114.12010612.8148356.3.f3c776c7ooFbkn How about something like that? It says its communicating using serial. In theory it should be usable with RPi. BTW, I am after measuring total volts on the serial connected batteries. I would...
by davidcoton
Mon Jul 15, 2019 1:40 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 30
Views: 966

Re: Want to measure battery volts

I was also thinking about the effective voltage range that you are going to measure on each battery. I am thinking that if the 12V battery drops to 6V, it will be in deep cycle. Also, open circuit measurement of a 12V battery can be as high as 13V. Maybe your effective measurement range would be be...
by davidcoton
Sun Jul 14, 2019 9:17 pm
Forum: Beginners
Topic: (Possibly pre-beginner!) Sensing simple closed circuit.
Replies: 8
Views: 197

Re: (Possibly pre-beginner!) Sensing simple closed circuit.

It's a shot in the dark but if you coiled a wire around the hot leg to the switch it would induce a small current in the wire, like those clamp-on ammeters. You might be able to work with that. Actually, that's not how clamp meters work. They use a toroidal ferrite with a coil round it, the conduct...
by davidcoton
Sun Jul 14, 2019 7:33 pm
Forum: Beginners
Topic: (Possibly pre-beginner!) Sensing simple closed circuit.
Replies: 8
Views: 197

Re: (Possibly pre-beginner!) Sensing simple closed circuit.

neilgl wrote:
Sun Jul 14, 2019 5:23 pm
You probably do not want to coil any wires around any mains voltage cable - too dangerous.
+1. Unless you understand Wiring Regs, insulation voltage, and isolation voltage don't try it.
If you do understand enough to try it safely, you probably won't want to. :o
by davidcoton
Sun Jul 14, 2019 7:28 pm
Forum: Beginners
Topic: interfacing Raspberry PI 3 and pulse oximeter.
Replies: 2
Views: 73

Re: interfacing Raspberry PI 3 and pulse oximeter.

Have you tried searching the forum for "oximeter"? There a re several threads that may (or may not) be useful.
by davidcoton
Sun Jul 14, 2019 7:13 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 30
Views: 966

Re: Want to measure battery volts

Here is how I wired it up to the RPi. MCP3008 Pin --> Raspberry Pi Header Pin Vdd --> 3V3 Vref --> 5V (Quoted with correction) There are two problems with that: Vref should not exceed Vdd You need a noise-free reference, 3V3 and (worse) 5V Pi supplies are not suitable. You should use a high-precisi...
by davidcoton
Sun Jul 14, 2019 11:32 am
Forum: General discussion
Topic: What's the simple and safe way to do a "shutdown" button?
Replies: 5
Views: 276

Re: What's the simple and safe way to do a "shutdown" button?

Try this: It's a tutorial I wrote a while back that lets you shutdown a Raspberry Pi with a paperclip shorting across the last two GPIO pins on the right: https://www.recantha.co.uk/blog/?p=13999 Just wire up a button if you don't want to use the paper clip :-) This is dangerous. If you have the bo...

Go to advanced search