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by davidcoton
Sun Oct 21, 2018 10:44 pm
Forum: Off topic discussion
Topic: Add Analog to Digital pins to the pi
Replies: 12
Views: 953

Re: Add Analog to Digital pins to the pi

Going by this logic, I neither need nor want POE, yet if I want a Pi3b+, I must accept it. Overall, it benefits more people who can afford those expensive POE routers, so it was added. Analogue input is a commonly requested feature I see here, the request to have it on the board itself isn't as out...
by davidcoton
Thu Oct 18, 2018 9:35 pm
Forum: Advanced users
Topic: Using my Pi with an AC mains connected preamp.
Replies: 12
Views: 370

Re: Using my Pi with an AC mains connected preamp.

That should indicate if it's double-isolated etc, good and safe to use. By law it should be double insulated Don't confuse insulation with isolation. Insulation protects the user from contacting mains voltage (or other electrical paths). In particular "double insulation" is a specification for main...
by davidcoton
Thu Oct 18, 2018 7:23 pm
Forum: General discussion
Topic: 64-bit operating system
Replies: 111
Views: 11236

Re: 64-bit operating system

Many years ago, when "state of the art" budget computing was Ti-58 programmable calculator, I wrote a program to calculate perfect numbers with something like 10 times the number of digits that the calculator handled natively. The code was possibly non-trivial, but not that complex. It would have be...
by davidcoton
Tue Oct 16, 2018 10:43 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3 B Possibly Broken
Replies: 2
Views: 103

Re: Raspberry Pi 3 B Possibly Broken

If you have a multimeter, carefully monitor the voltage on pin 1 of the GPIO header https://pinout.xyz/# . It should be 3V3. If not the regulator has died. It is not repairable unless you have SMT soldering equipment and experience. Do not short pin 1 to anything else while measuring! If you do, the...
by davidcoton
Tue Oct 16, 2018 10:34 pm
Forum: Beginners
Topic: 110 Volt status light
Replies: 2
Views: 80

Re: 110 Volt status light

So I assume you have one relay as a Pi output working the fog machine. I hope everything is properly enclosed and the board (not just the relay) is properly designed for switching mains (many low-cost relay boards are not suitable, but telling which is which requires knowlege of the mains wiring cod...
by davidcoton
Tue Oct 16, 2018 10:17 pm
Forum: General discussion
Topic: USB Boot
Replies: 17
Views: 1337

Re: USB Boot

To answer the original question, the Pi will always boot from SD card, regardless of the state of the OTP boot bit. Programming that bit just allows the older Pi3B to also boot from USB. However, SD card still has priority. So if you have a bootable SD card and USB drive, it will boot from the SD c...
by davidcoton
Tue Oct 16, 2018 10:11 pm
Forum: General discussion
Topic: looking to build an arcade box in a flight case
Replies: 7
Views: 177

Re: looking to build an arcade box in a flight case

When i say 12v socket, what i mean is one of the USB charge sockets you can buy online for vehicles which has both 1.0 amp and 2.5amp usb connections. The point is you must be sure exactly what you are connecting to. Standard USB sockets run at 5V. The Pi requires 5V. If your USB sockets are standa...
by davidcoton
Mon Oct 15, 2018 8:40 pm
Forum: General discussion
Topic: Need help with Pi3 temperature management
Replies: 12
Views: 2528

Re: Need help with Pi3 temperature management

Imperf3kt wrote:
Mon Oct 15, 2018 8:16 pm
You don't need a transistor to control the relay, you can use a regular SPDT switch.

You lose the automated part of the process, but it does the same trick.
But if you use a switch, so it is a manual process, you don't need a relay. The switch can control the fan directly.
by davidcoton
Mon Oct 15, 2018 4:43 pm
Forum: Português
Topic: Fonte com subtensão
Replies: 2
Views: 92

Re: Fonte com subtensão

Hello guys, I purchased a Rasberry PI 3 B + and recently bought a source from a website that said to be specific to Raspberry. It turns out that when using the source appears a radius icon indicating power failure (undervoltage). But this icon only appears once in a while, whenever the processor is...
by davidcoton
Mon Oct 15, 2018 4:18 pm
Forum: General discussion
Topic: Need help with Pi3 temperature management
Replies: 12
Views: 2528

Re: Need help with Pi3 temperature management

I want to know if I can use a relay module in place of the transistor. In this way, the GPIO port activates the relay allowing power to the fan. Are you using a ready-built Pi-compatible relay board, or a bare relay? A relay by itself probably won't work from the GPIO, it will need a transistor to ...
by davidcoton
Mon Oct 15, 2018 4:12 pm
Forum: General discussion
Topic: smart power consumption monitoring system
Replies: 3
Views: 132

Re: smart power consumption monitoring system

First off, we're talking of a project involving mains power. Are you familiar with the dangers of mains (electrocution, fire and destruction of Pi), and the practices necessary to stay safe? There are different ways of measuring mains current, some are intrusive , some rely on electromagnetic coupli...
by davidcoton
Mon Oct 15, 2018 4:02 pm
Forum: General discussion
Topic: How to boot into a user account (instead of the pi account)
Replies: 16
Views: 10721

Re: How to boot into a user account (instead of the pi account)

StampNScrap27 wrote:
Sun Oct 14, 2018 9:51 pm
HOW do you change the text for autologin-user=pi to autologin-user=Yearbook?
Nano is an editor. Just click on the line of text and type! Delete and cursor keys will also work.
Back to Superninja's instructions when it looks right.
by davidcoton
Sun Oct 14, 2018 10:44 am
Forum: Beginners
Topic: Flick-Large demo won't run on PI3
Replies: 13
Views: 1121

Re: Flick-Large demo won't run on PI3

I'm building a smart house and don't have any light switches whatsoever in the house and wanted the controls for lights to be hidden behind drywall in obvious places where a light switch would be typically mounted. I think you need to check the wiring regulations in your area. In the UK all mains c...
by davidcoton
Thu Oct 11, 2018 7:52 pm
Forum: Troubleshooting
Topic: Have I burned my Pi
Replies: 6
Views: 219

Re: Have I burned my Pi

Your first resource for boot problems is the Boot Problems Sticky . When you have read that and tried the appropriate things, if you still have a problem you can post here with more details -- especially, is this a Pi3B or a Pi3B+, and which OS are you loading when you use NOOBS? Better still, try R...
by davidcoton
Wed Oct 10, 2018 9:57 pm
Forum: General discussion
Topic: under voltage detected
Replies: 19
Views: 444

Re: under voltage detected

LTolledo wrote:
Wed Oct 10, 2018 9:48 pm
5v must not go below 4.9v nor beyond 5.15v
That's a bit cautious. The Pi spec allows 4V75-5V25 at the microUSB socket. Those limits should be maintained from Pi shutdown to full load.
by davidcoton
Tue Oct 09, 2018 10:43 pm
Forum: Troubleshooting
Topic: PI 3B+ not booting. Act led not blinking
Replies: 25
Views: 2036

Re: PI 3B+ not booting. Act led not blinking

Do you have a multimeter or oscilloscope? If so, measure the voltage on pin 1 of the GPIO connector. It should be 3V3. Be very careful not to short pin1 to anything else, if you do, the Pi will be dead afterwards even if it wasn't before.
by davidcoton
Mon Oct 08, 2018 8:23 am
Forum: Beginners
Topic: Raspberry Pi Model 3B+ can not boot
Replies: 8
Views: 241

Re: Raspberry Pi Model 3B+ can not boot

Do you have a multimeter or oscilloscope? If so, measure the voltage on pin 1 of the GPIO connector. It should be 3V3. Be very careful not to short pin1 to anything else, if you do, the Pi will be dead afterwards even if it wasn't before.
by davidcoton
Sun Oct 07, 2018 9:53 pm
Forum: Troubleshooting
Topic: raspberry pi 3b+ with old preloaded sd card
Replies: 9
Views: 215

Re: raspberry pi b+ old preloaded sd card

The blink codes are helpful... but I generally leave those icon overlay indicators out, as they can cause problems in a DLP setup where the monitor is part of the printer medium exposure process. ;-) It's a diagnostic which is useful for users of mainline OSs. If your speciality OS leaves out such ...
by davidcoton
Sun Oct 07, 2018 3:51 pm
Forum: Troubleshooting
Topic: raspberry pi 3b+ with old preloaded sd card
Replies: 9
Views: 215

Re: raspberry pi b+ old preloaded sd card

that lightning bolt usually means your power supply is not good enough, and you should look for a >3A 5v supply. Probably not the case here. The lightning bolt appears along with the four long four short flash pattern when trying to load pre-Pi3B+ OSs on a Pi3B+. It occurs because of the hardware/f...
by davidcoton
Sun Oct 07, 2018 3:29 pm
Forum: General discussion
Topic: Need Help Building A Vending Machine
Replies: 2
Views: 93

Re: Need Help Building A Vending Machine

You seem to have made a good start already by working out the parts of your project, and you know that the next bit is working out how to connect the parts (the key word is "interface"). Look for the Pi computer GPIO specification here and here on this site (click through the links), and the equival...
by davidcoton
Sun Oct 07, 2018 12:34 am
Forum: Troubleshooting
Topic: Solved: Raspberry pi 3 b+ will not boot.
Replies: 22
Views: 414

Re: My Raspberry pi 3 b+ will not boot. help needed

4.86 volts is not low enough to prevent a RPI 3B+ at least starting to boot with flashes of the green ACT LED and something on a suitable attached HDMI display. While this is true, a meter masks the actual waveform and therefore the voltage minima. 4.86V is indicative of a poor PSU, or a poor cable...
by davidcoton
Sat Oct 06, 2018 11:22 pm
Forum: Troubleshooting
Topic: SOLVED - Pi3B Rev1.2 - Boot Problems with Stretch
Replies: 23
Views: 591

Re: Pi3B Rev1.2 - Boot Problems with Stretch

Something is unique in my situation. Indeed, and interesting ... though I don't assume you find it so :!: :( The flashing LED pattern is the same one that usually indicates that a Pi3B+ cannot boot an image with out of date firmware/kernel. (Then it appears on the other LED due to hardware differen...
by davidcoton
Sat Oct 06, 2018 11:13 pm
Forum: Troubleshooting
Topic: Solved: Raspberry pi 3 b+ will not boot.
Replies: 22
Views: 414

Re: My Raspberry pi 3 b+ will not boot. help needed

4.86 volts is not low enough to prevent a RPI 3B+ at least starting to boot with flashes of the green ACT LED and something on a suitable attached HDMI display. While this is true, a meter masks the actual waveform and therefore the voltage minima. 4.86V is indicative of a poor PSU, or a poor cable...
by davidcoton
Sat Oct 06, 2018 11:00 pm
Forum: Troubleshooting
Topic: Cannot install WiFi on Raspberry 3 B
Replies: 8
Views: 258

Re: Cannot install WiFi on Raspberry 3 B

Some possible causes of problems are: Poor power supply Removing power without shutting down Faulty, worn out or fake SDCard Running faulty versions of software under development (safer on ARM under Linux than on some other platforms!). You can mitigate some of these issues, but ultimately you need ...
by davidcoton
Sat Oct 06, 2018 10:43 pm
Forum: Troubleshooting
Topic: Solved: Raspberry pi 3 b+ will not boot.
Replies: 22
Views: 414

Re: My Raspberry pi 3 b+ will not boot. help needed

I don't think a 2.1A power supply is enough for a RPi3B+. It may be enough for a RPi3B, I don't know, but the Foundation recommends at least a 2.5A supply for a 3B+. I guess you will have to take it up with your supplier. The extra power is necessary if you use lots of USB devices. for just a keybo...

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