Go to advanced search

by Burngate
Mon Feb 04, 2019 7:10 pm
Forum: Troubleshooting
Topic: Low voltage warning on boot
Replies: 24
Views: 685

Re: Low voltage warning on boot

... when is a PSU an actual PSU as opposed to a charger? Like many things, it probably depends on who's talking. But the way I would use the terms, what you connect to your phone is a charger, because its primary purpose is to charge the battery - the phone uses its battery as its power supply. The...
by Burngate
Mon Feb 04, 2019 6:54 pm
Forum: HATs and other add-ons
Topic: Official Raspberry Pi power supply -- adding power switch
Replies: 8
Views: 877

Re: Official Raspberry Pi power supply -- adding power switch

Disclaimer: I'm probably out of my tree, if not actually wrong.

The pictures show a mains connection I'm not familiar with, but seems to be reversible.
If that's true, what happens if you reverse it?
by Burngate
Mon Feb 04, 2019 12:00 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 5354

Re: Resistors and MOSFETs and fire-prevention, oh my

danjperron wrote:
Sun Feb 03, 2019 6:38 pm
Capture d’écran 2019-02-03 à 13.37.19.png
Just a note: This diagram is far nicer than mine, and better than any I've seen done in Fritzing.
So it might be worth asking what program he's using
by Burngate
Sun Feb 03, 2019 11:41 am
Forum: Off topic discussion
Topic: Why I love my PIs
Replies: 33
Views: 2180

Re: Why I love my PIs

IT guys tend to be quite conservative - they know a Windows tower works, they know the users know how to use it, and when things go wrong they know how to fix it quickly, even if that means spending money on a new tower. The Pi is priced low, so that when things go wrong it's not too costly to repla...
by Burngate
Sun Feb 03, 2019 10:02 am
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 5354

Re: Resistors and MOSFETs and fire-prevention, oh my

The resistor between GPIO and gate: large enough that current from the GPIO is lower than it can handle. Since the GPIO can't provide more than ~15mA and 3v3, Ohms law says more than 220 ohms. 1k would be enough. So would 470 or 330, depending on what you have in your bits-box. For the resistor from...
by Burngate
Sat Feb 02, 2019 7:08 pm
Forum: Beginners
Topic: Resistors and MOSFETs and fire-prevention, oh my
Replies: 156
Views: 5354

Re: Resistors and MOSFETs and fire-prevention, oh my

A couple of things. You're labelling the pins of the MOSFET as middle = Source, right, and gate. But the datasheet you linked to has two drawings - TO-220AB & TO-263AB - neither of which has the source in the middle, so I'm confused. From your description, I think you have: _________ +12V | | | --- ...
by Burngate
Fri Feb 01, 2019 7:09 pm
Forum: General discussion
Topic: MOSFET IRF520
Replies: 8
Views: 318

Re: MOSFET IRF520

As far as I'm aware, controlling mains devices such as these is normally done using triacs with phase-control rather than PWM Firing the triac part-way through each half-cycle limits the time current flows, hence the power. Before you try that at home, it's worth while finding out how to keep the ma...
by Burngate
Fri Feb 01, 2019 6:44 pm
Forum: General discussion
Topic: How many pieces of pi are too many?
Replies: 72
Views: 2104

Re: How many pieces of pi are too many?

One of the interesting differences between Neanderthals and "us" is that "they" made multipurpose stone tools, while "we" made lots of different sorts of specialist ones. Of course "them" and "us" is an artificial dichotomy - unless all your ancestors remained in southern Africa you've probably got ...
by Burngate
Fri Feb 01, 2019 6:36 pm
Forum: Off topic discussion
Topic: Why I love my PIs
Replies: 33
Views: 2180

Re: Why I love my PIs

Where are these in your list? Vonnegut - Slaughterhouse 5 & The Sirens of Titan (still not got Player Piano) Olaf Stapleton - Last and First Men Robert Heinllein - The Number of the Beast Larry Niven - Ringworld I used to be able to pick out any of my books and give a short precis of it Since having...
by Burngate
Fri Feb 01, 2019 12:17 pm
Forum: Off topic discussion
Topic: Why I love my PIs
Replies: 33
Views: 2180

Re: Why I love my PIs

Two kayaks (used to have more), 2000 SF books, several Pis.
Not enough room for more kayaks, and running out of wall-space for books. At least the Pis don't take up much room - yet.

Some people collect guitars, others collect stamps.
by Burngate
Fri Feb 01, 2019 12:10 pm
Forum: Troubleshooting
Topic: RPi GPIO Activates on Hard Shutdown/Power On
Replies: 8
Views: 247

Re: RPi GPIO Activates on Hard Shutdown/Power On

The gate board uses three pins on its control board...Open, Close, and Ground. I have GPIO pin 7 plugged into the ground , GPIO 15 into close, and GPIO 19 into open. Why pin 7 to ground? Ground can be found on several pins - 6, 9, 14, 20, 25, ... - and is a reference against which the gate-control ...
by Burngate
Fri Feb 01, 2019 11:55 am
Forum: General discussion
Topic: Translation issues
Replies: 49
Views: 1562

Re: Translation issues

Actually, my use of my Hawaiian US amateur radio call sign as a nickname pretty well nails down my location. Seemed silly and redundant to specify the obvious. An interesting viewpoint. I've just put your call sign into Google and found that WH7QQ (yourself) as well as KH7SF, WH6TT and K9FD live in...
by Burngate
Thu Jan 31, 2019 12:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Sending all GPIO pins low at boot
Replies: 4
Views: 320

Re: Sending all GPIO pins low at boot

It might be worth-while looking at https://pinout.xyz/# for the mappings between board and BCM numbering. As for ... This could be quite problematic ... could make a real mess of my peripherals ... some motorised moving parts to so there is a small potential for physical damage of parts crushing aga...
by Burngate
Wed Jan 30, 2019 6:14 pm
Forum: HATs and other add-ons
Topic: Using 16 channel reply
Replies: 2
Views: 141

Re: Using 16 channel reply

That is a bit too vague.

What do you want to achieve with the buttons?
When you push a button, what do you want to happen?

I think your best course of action would be to first draw a diagram of what you want to do, and how you think it should all be connected together.
by Burngate
Wed Jan 30, 2019 11:58 am
Forum: General discussion
Topic: How many pieces of pi are too many?
Replies: 72
Views: 2104

Re: How many pieces of pi are too many?

Gavinmc42 wrote:
Wed Jan 30, 2019 11:24 am
We need more Pi
3.14159... isn't enough
by Burngate
Wed Jan 30, 2019 10:38 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing with absolute encoder via SSI
Replies: 1
Views: 146

Re: Interfacing with absolute encoder via SSI

Direct bit banging doesn't seem possible either, as it's a differential signal Are you sure about this? It doesn't seem to have enough wires to be SSI as in https://en.wikipedia.org/wiki/Synchronous_Serial_Interface Rather, it appears to be SSI as in https://en.wikipedia.org/wiki/Simple_Sensor_Inte...
by Burngate
Wed Jan 30, 2019 9:51 am
Forum: Other projects
Topic: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it
Replies: 49
Views: 47993

Re: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it

I used to not notice things, but at one point my wife was a proof-reader, and I think things sort of rubbed off on me.
by Burngate
Tue Jan 29, 2019 6:18 pm
Forum: Beginners
Topic: Remote control and monitoring of a diesel generator
Replies: 7
Views: 350

Re: Remote control and monitoring of a diesel generator

Remote monitoring: ok. Remote control: NO You don't say how big the generator is. At race courses we used a couple of stand-alone generators (30kVA & 70kVA) as well as the ones built in to the scanners. They were never operated without someone sitting in the cab. That's because, as well as 240V AC f...
by Burngate
Tue Jan 29, 2019 6:01 pm
Forum: Other projects
Topic: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it
Replies: 49
Views: 47993

Re: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it

npaisnel - Just as an aside, the last two times you've quoted someone, you've managed to miss the forward slash (/) in the end-quote mark. Quite how you managed it I don't know, but it messes up the prettiness of the thread!
Totally off-topic, I know, but I don't care!
by Burngate
Tue Jan 29, 2019 11:19 am
Forum: General discussion
Topic: How many pieces of pi are too many?
Replies: 72
Views: 2104

Re: How many pieces of pi are too many?

28 March 2012: The good news is that our first 2,000 boards arrived in the UK on Monday and that we are working to get them CE marked as soon as is humanly possible, in parallel with bringing the remainder of our initial batch into the country. https://www.raspberrypi.org/blog/an-update-on-ce-compli...
by Burngate
Mon Jan 28, 2019 5:54 pm
Forum: Other projects
Topic: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it
Replies: 49
Views: 47993

Re: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it

1st point: an in-line switch introduces resistance. Even if it's not been used, the contacts won't be perfect - that is, not as perfect as a piece of copper wire. And any resistance is bad, because you're wanting a variable current up to 2.5A to flow while keeping the end voltage within about 0.5v. ...
by Burngate
Mon Jan 28, 2019 12:18 pm
Forum: Other projects
Topic: Controlling several electromagnets
Replies: 8
Views: 612

Re: Controlling several electromagnets

The diode doesn't of itself provide resistance - it just has a forward voltage drop of 0.6-0.7V. It just (effectively) provide a path for the current to flow. Al it needs to do is carry the current you've been supplying - look on its datasheet to find out whether it can carry that current. When the ...
by Burngate
Mon Jan 28, 2019 12:07 pm
Forum: Other projects
Topic: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it
Replies: 49
Views: 47993

Re: Adding a 5V Fan to a Raspberry Pi 3 Model B and having control of it

It's a bad idea to plug the fan connectors directly to the RPI GPIO pins because the fan needs a burst of current when it starts running and it's also dangerous when it stops because it may send a harmful current to the ground pin Yes, it is a very bad idea to plug a fan (or other, high-current ind...
by Burngate
Mon Jan 28, 2019 11:53 am
Forum: Automation, sensing and robotics
Topic: Household fan speed
Replies: 2
Views: 155

Re: Household fan speed

What sort of "ceiling fan"? If it already has some sort of speed control, you may be able to interface with that. If it's just a mains-operated one, you're probably not going to be able to control it - particularly as mains is dangerous. Diving in without knowing more about the depth of the water, o...
by Burngate
Mon Jan 28, 2019 11:48 am
Forum: Beginners
Topic: Pi 3 B+ Booted now doesn’t
Replies: 10
Views: 320

Re: Pi 3 B+ Booted now doesn’t

Surely that question is the same as "Why did the San Andreas fault slip in 1906?"

Go to advanced search