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by Burngate
Fri Jun 18, 2021 9:18 am
Forum: Python
Topic: keyboard input to Pi - reversing normally off to on?
Replies: 2
Views: 118

Re: keyboard input to Pi - reversing normally off to on?

I've setting up a conventional manual typewriter with sensors to feed key strokes to a Pi. I do hope you post some pictures when you're done! My keys, unlike a normal keyboard, will all be in the "on" state (due to the mechanics of it all). In other words, pressing a key will send an off ...
by Burngate
Wed May 26, 2021 9:41 am
Forum: Compute Module
Topic: Any plans for more 'stock' ?
Replies: 21
Views: 1037

Re: Any plans for more 'stock' ?

I wonder how Trump caused the drought that's currently giving TSMC such problems, and why, given TSMC is Taiwanese, not Chinese
by Burngate
Thu May 20, 2021 6:07 pm
Forum: Troubleshooting
Topic: Buttons not getting a good read
Replies: 12
Views: 366

Re: Buttons not getting a good read

I find that insulting.

Since we're here to help, deliberately putting wrong information here seems a bad idea.
by Burngate
Thu May 20, 2021 9:49 am
Forum: Troubleshooting
Topic: Buttons not getting a good read
Replies: 12
Views: 366

Re: Buttons not getting a good read

According to what I've read, WiringPi 17 is BCM 28, which hasn't been available since very early boards (it was available as PCM_CLK on a separate header)

https://pinout.xyz/# is a very useful source of info to work out what can be done with GPIOs and what to call them
by Burngate
Thu May 20, 2021 9:41 am
Forum: Troubleshooting
Topic: Buttons not getting a good read
Replies: 12
Views: 366

Re: Buttons not getting a good read

mosfets are the switch family of semiconductors. Unlike transistors, that you have to bias, once it has reached its threshold voltage, it turns on to full conduction. Not true. Once the threshold voltage is reached, it begins to turn on, but won't conduct significantly until a higher gate-source vo...
by Burngate
Tue May 18, 2021 5:52 pm
Forum: General discussion
Topic: Is it possible to have multiple accelerometer in pi zero ?
Replies: 4
Views: 270

Re: Is it possible to have multiple accelerometer in pi zero ?

One on each hoof going over Bechers, or one on each limb and one on the head coming off there.

One on each hoof and one on each wing of Pegasus.

I could go on, but I won't.
by Burngate
Tue May 11, 2021 5:25 pm
Forum: Off topic discussion
Topic: Help identifying tiny chip
Replies: 28
Views: 2394

Re: Help identifying tiny chip

razzjazz192 wrote:
Tue May 11, 2021 1:37 am
I recently ordered a bunch of electronic components, and out of one of those packages, ...
Who from? What components? What else was in that package?
by Burngate
Mon May 10, 2021 5:00 pm
Forum: Beginners
Topic: Reading GPIO pins resistance
Replies: 3
Views: 150

Re: Reading GPIO pins resistance

You don't say which GPIOs (or pins) your buttons are connected to, but it's worth knowing that, apart from the first few, most GPIOs have the pull-down enabled by default. That would probably measure as about 50k, and would also mean the Pi would register them as "pressed" - exactly your s...
by Burngate
Mon May 10, 2021 11:25 am
Forum: Automation, sensing and robotics
Topic: Interfacing GPIO with a 12V device
Replies: 6
Views: 410

Re: Interfacing GPIO with a 12V device

According to the first page, under Features, it says: "4. Current transfer ratio (CTR : MIN. 50% at IF=5 mA, VCE=5V)" (Note: the closing bracket ended up in the wrong place; it should say "4. Current transfer ratio (CTR) : MIN. 50% at IF=5 mA, VCE=5V". They weren't very good at w...
by Burngate
Mon May 10, 2021 9:27 am
Forum: Automation, sensing and robotics
Topic: Interfacing GPIO with a 12V device
Replies: 6
Views: 410

Re: Interfacing GPIO with a 12V device

It should work ... using the internal pull-up resistor (whose Ohms I don't know). It's about 50k I would consider adding my own pull-up resistor, of about 10k, but I'm old-fashioned Do I even need R1? If so, is it appropriately sized? You don't really need it. But if you do add your own 10k pull-up,...
by Burngate
Sat May 08, 2021 6:10 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO output LOW shortly connected to 3.3V rail
Replies: 3
Views: 183

Re: GPIO output LOW shortly connected to 3.3V rail

The output stage of a GPIO consists of a pair of FETs, one to pull to 3v3, the other to pull to 0v (actually more than one pair, but that's irrelevant) If anything got damaged, it was the lower of the pair, and may no longer switch fully off. What's more, driving that GPIO high (switching on the upp...
by Burngate
Fri May 07, 2021 6:32 pm
Forum: General discussion
Topic: Which pi is which
Replies: 40
Views: 1851

Re: Which pi is which

We have been considering if it's feasible to put some sort of memory size marker on the board, not sure if we have got a scheme yet. You can get laser engravers that work on moving product, a product from a sister company a few jobs back had something called a Beer blaster which could put BB dates ...
by Burngate
Fri May 07, 2021 6:17 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO output LOW shortly connected to 3.3V rail
Replies: 3
Views: 183

Re: GPIO output LOW shortly connected to 3.3V rail

It seems like my RPI 3b did not get injured as the GPIO is still functional: is there any explanation it survived this short circuit? What does due time mean in this context? ... Eventually, I'd just like to know if it is still safe to use this same Raspberry Pi. First point ... a Pi's life should ...
by Burngate
Wed May 05, 2021 8:55 am
Forum: Advanced users
Topic: gpio-shutdown lingering voltage
Replies: 6
Views: 430

Re: gpio-shutdown lingering voltage

If the FET is switched off, the whole of the Zero's circuit will be at Vcc - 5v - and that includes the GPIOs. The only reason the GPIO doesn't have 5v on it is, when unpowered, its output circuit (a couple of FETs) will not be powered. There will, however be paths for current to flow from elsewhere...
by Burngate
Thu Apr 15, 2021 5:59 pm
Forum: Beginners
Topic: Control LED matrix from Rpi3
Replies: 3
Views: 151

Re: Control LED matrix from Rpi3

... but I don't know that much about hardware How much don't you know? How much further on than making an LED flash on command? These matrices are very much more complicated. You'll notice there are two 16-pin connectors, one for data input and the other for daisy-chaining to the next one. However ...
by Burngate
Mon Apr 12, 2021 11:17 am
Forum: General discussion
Topic: Raspberry Pi 4 - Not switching on
Replies: 2
Views: 189

Re: Raspberry Pi 4 - Not switching on

The Pi 4 doesn't have a polyfuse, so that wasn't the problem!
If there's no red LED lit, power isn't reaching the Pi, so the first thought has to be the power supply. But are you sure it's properly connected? Is the plug fully home?
by Burngate
Sat Apr 10, 2021 5:56 pm
Forum: General discussion
Topic: Power source
Replies: 6
Views: 271

Re: Power source

LTolledo wrote:
Fri Apr 09, 2021 10:29 pm
there is also very novel "non-exhaustive" power source that's being developed....but still in early stage of development.....
Would that be the Dark Energy one? It just keeps getting bigger and bigger, and it's only 13 Gy old so far.
by Burngate
Fri Apr 09, 2021 6:08 pm
Forum: Advanced users
Topic: Cutting Raspberry Pi Zero To Reduce Size
Replies: 15
Views: 627

Re: Cutting Raspberry Pi Zero To Reduce Size

Given that a Zero has only two layers, you should be able to see which tracks go where, and what's been mashed up.
A file to remove the mashings, and a bit of fine wire to replace and lost connections ... for a fiver, it might be worth trying!
by Burngate
Fri Apr 02, 2021 9:16 am
Forum: Graphics, sound and multimedia
Topic: Record audio from old telephone to rpi zero.
Replies: 7
Views: 531

Re: Record audio from old telephone to rpi zero.

A couple of questions: Is it really the one pictured, which isn't a really old one but a modern look-alike, or is it a 1940s/50s one? And how much modification are you willing to do to it? A really old one will have nothing much inside it other than a bell, a transformer, the dial mechanism, and the...
by Burngate
Fri Apr 02, 2021 8:40 am
Forum: Advanced users
Topic: Will a hard drive magnet attached to the Pi Case cause data corruption issues?
Replies: 6
Views: 440

Re: Will a hard drive magnet attached to the Pi Case cause data corruption issues?

There are a few components on the board that might be compromised - the inductors round the PMIC are working close to saturation when the Pi's doing a lot of work and using a lot of current, so a very high magnetic field could maybe take them into saturation. Doubtful, but maybe worth experimentation.
by Burngate
Tue Mar 30, 2021 9:19 am
Forum: Troubleshooting
Topic: Trying to avoid relay issues
Replies: 5
Views: 211

Re: Trying to avoid relay issues

3) GPIO 17 pops up in many tutorials, but am I free to use almost any GPIOs (e.g. 2, 3, 4, 5, 6) to control relays? You can use any GPIO, as long as it isn't in use for anything else. So GPIO 4 is often used by the 1-wire system. But if you disable the 1-wire can use 4 as a normal GPIO. https://pin...
by Burngate
Sat Mar 27, 2021 7:34 pm
Forum: Beginners
Topic: Extension micro usb power cable for Pi3B+
Replies: 4
Views: 209

Re: Extension micro usb power cable for Pi3B+

Power extension cables are really only good for temporary use; best solution would be a properly installed power point beside your Pi. But what I would do (not saying you should) is staple the extension cable to the wall, and fix the socket to the wall next to the Pi. At least that way you wouldn't ...
by Burngate
Thu Mar 18, 2021 6:32 pm
Forum: Troubleshooting
Topic: Audio noise problem
Replies: 5
Views: 270

Re: Audio noise problem

it wouldn't hurt putting those...specially if the the amp is to be used with audio devices Actually it might ... those caps aren't very good if they're not biased close to their rated voltage. At low positive voltage they go leaky, and taking them negative (as the audio will) can slowly destroy the...
by Burngate
Mon Mar 15, 2021 7:01 pm
Forum: Beginners
Topic: Can't find my post
Replies: 7
Views: 317

Re: Can't find my post

Strange, indeed. When I click on your user name, it tells me you've made 2 posts, but it can't find either of them, despite me having your second one right in front of me.
We'll see what happens to this post of mine!

Edit: it can now see this thread.

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