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by Burngate
Sun Dec 17, 2017 5:15 pm
Forum: General discussion
Topic: 12V relay schematics
Replies: 7
Views: 203

Re: 12V relay schematics

Your first post implied you'd changed the 5v relay for a 12v one, and put 12v on the pin labelled "+5v", everything else the same. And later you say the relay clicks, so that bit is correct. But ... the voltage in the relay's spec. sheet is just the voltage the coil inside needs, nothing to do with ...
by Burngate
Sun Dec 17, 2017 4:58 pm
Forum: General discussion
Topic: Running a pair of 4Ohm, 3W speakers from the Pi.
Replies: 5
Views: 99

Re: Running a pair of 4Ohm, 3W speakers from the Pi.

I read the title to mean 4Ω speakers, not 40Ω.
In which case my trusty calculator says 5v peak means 3.125 W RMS into 4Ω (assuming push-pull)
The only problem is the current, 1.25A for each speaker so 2.5A total and none left for the Pi.
by Burngate
Sun Dec 17, 2017 10:56 am
Forum: Beginners
Topic: Controlling electric roller blinds
Replies: 4
Views: 119

Re: Controlling electric roller blinds

Some things you might want to consider. If the roller blind will stop at top and bottom, and the motor is happy to stall without breaking, and its power supply is happy to provide the stall-current the motor wants, then adding a current-sensing circuit into the system could tell you when it reaches ...
by Burngate
Sat Dec 16, 2017 10:19 am
Forum: General discussion
Topic: How come the price hasn't gone down?
Replies: 29
Views: 829

Re: How come the price hasn't gone down?

What about Moore's Law? Well ... what about it? Moore's law refers to the number of transistors on a lump of silicon. In the four years since the Pi launched, technology has improved, and the latest bleeding edge chips have (more or less) followed Moore's law ... but the Pi doesn't use bleeding edg...
by Burngate
Fri Dec 15, 2017 6:08 pm
Forum: Beginners
Topic: Using capacitive touch
Replies: 2
Views: 65

Re: Using capacitive touch

There are two I2C busses on the Pi; pins 3 & 5 (GPIOs 2 & 3, sda1 & scl1) and the one dedicated to Hats, pins 27 & 28 (GPIOs 0 & 1, sda0 & scl0)
How you access the other one I don't know, but it should be possible.
by Burngate
Fri Dec 15, 2017 11:22 am
Forum: General discussion
Topic: Zero 1.3 hardwired usb wifi disabling usb port
Replies: 10
Views: 341

Re: Zero 1.3 hardwired usb wifi disabling usb port

truefate wrote:
Fri Dec 15, 2017 8:06 am
... It's wired like a usb ...
... but is it actually usb? Saying it's 3.3v instead of 5v rather implies it isn't.
by Burngate
Fri Dec 15, 2017 10:07 am
Forum: General discussion
Topic: Jack audio output as a HIFI trigger
Replies: 7
Views: 247

Re: Jack audio output as a HIFI trigger

jayce996 wrote:
Thu Dec 14, 2017 9:28 am
... in the trigger entry of my power amp.
Quite possibly information about your power amp could be useful - make, model, ...
by Burngate
Fri Dec 15, 2017 9:40 am
Forum: Off topic discussion
Topic: What was your first computer?
Replies: 327
Views: 46141

Re: What was your first computer?

SC/MP? MK14? Tangerine?
by Burngate
Thu Dec 14, 2017 11:43 am
Forum: Troubleshooting
Topic: Pi 3 B won't boot, audible squealing coming from pi
Replies: 4
Views: 147

Re: Pi 3 B won't boot, audible squealing coming from pi

Since there is nothing on the Pi that could emit sound, apart from a few inductors which are in the power supply chain, I'm wondering what you are using for power supply. It could be that it has been slowly failing, unable to provide adequate current and going into oscillation.
by Burngate
Thu Dec 14, 2017 10:45 am
Forum: For sale
Topic: 59 Pi B+ For Sale
Replies: 5
Views: 189

Re: 59 Pi B+ For Sale

From his other posts, he's in New Zealand - unless he's emigrated.
by Burngate
Tue Dec 12, 2017 7:27 pm
Forum: Beginners
Topic: 1MOhms
Replies: 10
Views: 350

Re: 1MOhms

Strange. The English version hasn't got that, anywhere that I can find. I wonder if it loses 1.5W when carrying its full load - 25A - so that makes it about 2.4mΩ The one linked to is a two-pole one, but that shouldn't matter, though. ERC225-2.jpg From that, it looks like A1 and A2 aren't auxiliary ...
by Burngate
Tue Dec 12, 2017 10:14 am
Forum: Graphics, sound and multimedia
Topic: Using the test pads, how may I hardwire passive speakers?
Replies: 5
Views: 210

Re: Using the test pads, how may I hardwire passive speakers?

... I couldn't find anything on that specific model (regarding over or under powering), but I keep seeing it's better to overpower... That instructables amplifier board uses a pam8403 chip, and so all the relevent data (probably far more than you want!) can be found in https://www.diodes.com/assets...
by Burngate
Mon Dec 11, 2017 11:03 am
Forum: Beginners
Topic: Pi Zero Ripple Voltage
Replies: 3
Views: 132

Re: Pi Zero Ripple Voltage

... Pi Zero 1.3 ... powering it through the GPIO pins. I read that powering the Pi through the GPIO pins means bypassing the regulator No. The Pi has no 5v regulator, and the Pi Zero doesn't even have a fuse between the microUSB sockets and the GPIO header, so powering it through the header pins wo...
by Burngate
Sun Dec 10, 2017 11:01 am
Forum: The MagPi
Topic: Issue 64 of Magpi
Replies: 2
Views: 211

Re: Issue 64 of Magpi

As of 11 o'clock today, https://www.raspberrypi.org/magpi-issues/MagPi64.pdf is working.
by Burngate
Thu Dec 07, 2017 11:46 am
Forum: General discussion
Topic: High Precision AD/DA board ADS1256
Replies: 7
Views: 315

Re: High Precision AD/DA board ADS1256

The first 12 bits represent 1 part in 4k; the next hexadecimal digit takes it to 64k.
So if your input range is 2.5V your input could be changing by (of the order of) 40uV
Unless your reference voltage is changing by that much. Are you sure it isn't?
by Burngate
Wed Dec 06, 2017 6:16 pm
Forum: General discussion
Topic: OK. This is ridiculous!
Replies: 34
Views: 1596

Re: OK. This is ridiculous!

For what it's worth, I've gota couple of comments. First is the Moore's law syndrome and its corollary - not only do things get twice as complicated every two years, but also we expect twice as many bangs for our buck. So what was exciting, wonderful, an early Christmas present, a few years ago now ...
by Burngate
Wed Dec 06, 2017 9:46 am
Forum: Automation, sensing and robotics
Topic: Possible to read potentiometer values from a sensor?
Replies: 15
Views: 594

Re: Possible to read potentiometer values from a sensor?

Bourns 3362P-01.jpg
Bourns 3362P-01.jpg (4.65 KiB) Viewed 233 times
Bourns 3362P-02.jpg
Bourns 3362P-02.jpg (4.46 KiB) Viewed 233 times
Solder the wires to the pins on the under-side of the board.
by Burngate
Tue Dec 05, 2017 6:14 pm
Forum: Beginners
Topic: Safety Instructions
Replies: 18
Views: 648

Re: Safety Instructions

That put me in my place, didn't it! Pass on our congratulations for surviving, if you could, as well as our commiserations for being struck. So maybe I won't shelter under trees any more. Learning from one's own experience isn't necessarily the best option, when someone else's experience is availab...
by Burngate
Tue Dec 05, 2017 5:51 pm
Forum: General discussion
Topic: 3V3 rise time
Replies: 21
Views: 696

Re: 3V3 rise time

Quote from the Diodes Inc pdf: As the input voltage approaches the output voltage, the converter turns the P-Channel transistor continuously on. In this mode the output voltage is equal to the input voltage minus the voltage drop across the P-Channel transistor So the 3v3 rail starts rising as soon ...
by Burngate
Tue Dec 05, 2017 12:05 pm
Forum: Beginners
Topic: Safety Instructions
Replies: 18
Views: 648

Re: Safety Instructions

You're asking "What can go wrong?" Actually, the question should also include "How likely is it?", "What's the cost?" and "What's the cost of not doing it?" We're often told not to stand under a tree in a thunder storm, but I've known lots of people do so, and none of them has died. On the other han...
by Burngate
Mon Dec 04, 2017 6:41 pm
Forum: Beginners
Topic: 1MOhms
Replies: 10
Views: 350

Re: 1MOhms

brouno wrote:
Mon Dec 04, 2017 2:42 pm
... an automated switch
Can you give us more info about this?
by Burngate
Sun Dec 03, 2017 10:06 am
Forum: Beginners
Topic: Command line question
Replies: 7
Views: 318

Re: Command line question

Thankyou for that.
Having been brought up on RiscOs, I've always felt Linux to be a large mountain to climb. I've pottered round the lower slopes, but never felt at home. This looks like it might be the funicular I need.
by Burngate
Sat Dec 02, 2017 6:20 pm
Forum: General discussion
Topic: LM1084 power supply
Replies: 36
Views: 899

Re: LM1084 power supply

Forth ... yes. And Reverse Polish. I had a Sinclair Scientific - I may still have it somewhere ... and I may have bought or just wanted to buy a computer that ran Forth. I'll have to dig through the treasure trove. Somewhere below the VHS machine, and above my Neanderthal forebear's knuckle-bones.
by Burngate
Sat Dec 02, 2017 5:50 pm
Forum: General discussion
Topic: Pi Zero W availability
Replies: 110
Views: 5822

Re: Pi Zero W availability

"affordable enough for any project!" to me is an invitation to buy multiples To me, that doesn't mean you can run multiple projects concurrently - it means you could run your Christmas tree lights, then your Easter Bunny lights, then ... all with the same Zero. I figured the low cost was because it...
by Burngate
Sat Dec 02, 2017 12:03 pm
Forum: Troubleshooting
Topic: GPIO not going all the way LOW [solved]
Replies: 17
Views: 640

Re: GPIO not going all the way LOW

gordon77 wrote:
Sat Dec 02, 2017 11:10 am
I am confused
You and me, both.
Looking further at that image, almost nothing seems to go where I would have expected.
We'd all get along better if we could see a proper circuit diagram, rather than a board layout, and more than just the bit we're allowed to see.

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