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by Burngate
Thu Sep 05, 2019 10:25 am
Forum: Beginners
Topic: GPIO pin turns off immediately when switch is connected, turns back on when disconnected
Replies: 3
Views: 147

Re: GPIO pin turns off immediately when switch is connected, turns back on when disconnected

I'm not sure I understand your description. I have no problem turning on and off pins on my rpi4 ... so you've set the GPIOs to ouput , and you can set them to 0 (gnd) or 1 (3v3) at will. How are you checking they do what you want? A meter? a LED and resistor? however when I connect a wire (which is...
by Burngate
Thu Sep 05, 2019 9:06 am
Forum: Beginners
Topic: Connecting existing Doorbell (AC door bell with bell switch ) to raspberry pi 3 GPIO
Replies: 16
Views: 378

Re: Connecting existing Doorbell (AC door bell with bell switch ) to raspberry pi 3 GPIO

I don't suppose you could post some details of this doorbell - make, model, etc. - and maybe pictures of what's inside it?
We can all guess what it should be like, but reality often surprises us.
by Burngate
Wed Sep 04, 2019 6:18 pm
Forum: Beginners
Topic: Raspberry Pi ** Sold over 25million units **
Replies: 19
Views: 827

Re: Raspberry Pi ** Sold over 25million units **

epoch1970 wrote:
Wed Sep 04, 2019 1:41 pm
Indeed... Pi 4/4 in a solid gold case. A bit bling, but very good for cooling.
Diamond would be better
by Burngate
Tue Sep 03, 2019 9:31 am
Forum: Beginners
Topic: GPIO pull up resistors.
Replies: 4
Views: 201

Re: GPIO pull up resistors.

Internal 50k resistors can be applied as pull-ups or pull-downs, and before anything else happens, most GPIOs have pull-downs by default. If you leave them as-is, the internal 50k pull-downs together with your external 10k pull-ups give a potential divider, ending up with a pull to about 2.75v throu...
by Burngate
Mon Sep 02, 2019 5:43 pm
Forum: Off topic discussion
Topic: designing a rubic cube box
Replies: 11
Views: 1380

Re: designing a rubic cube box

That explains (I think - I, too, am a slow learner!) the black splodges on your drawing - his kneck and arm holes! You've got a couple of months, yet, before it needs to be finished, plenty of time - just so long as he doesn't grow out of his box! My understanding is that 20mA is the maximum current...
by Burngate
Mon Sep 02, 2019 11:30 am
Forum: Off topic discussion
Topic: designing a rubic cube box
Replies: 11
Views: 1380

Re: designing a rubic cube box

I've been a Rubik's Cube nut for the last ... is it really 45 years? I really should get out, more. I find your post most frustrating, and I doubt I'm the only one. For a start, my cubes don't look quite like your picture - they're quite symmetrical, with 6 3x3 faces (except one with 6 4x4 faces) so...
by Burngate
Mon Sep 02, 2019 10:32 am
Forum: Automation, sensing and robotics
Topic: Dust collection automation 20A circuit
Replies: 17
Views: 571

Re: Dust collection automation 20A circuit

I think I've been told one time too many that I'm out of my depth so I will end this conversation here and work on this on my own I would suggest you don't work on this on your own, but rather find someone close by who is familiar with equipment such as this to help you. After all, letting loose a ...
by Burngate
Sun Sep 01, 2019 9:36 am
Forum: Troubleshooting
Topic: Rasbperry Pi 3 B+ overheat problem
Replies: 5
Views: 160

Re: Rasbperry Pi 3 B+ overheat problem

I have used the GPIO ports to switch on transistors with a few milliAmps (~5 mA). What type of transistor, and how did you conect them? For example, if they were bipolar NPN, and you connected the emitter to gnd and the base to the GPIO without a series resistor, a large current could flow, enough ...
by Burngate
Sat Aug 31, 2019 10:13 am
Forum: Troubleshooting
Topic: Red light and it is not starting
Replies: 1
Views: 90

Re: Red light and it is not starting

Red LED blinking = power problem.

If it happens with multiple power supplies, then either none of them is good enough, or your Pi is faulty.

https://www.raspberrypi.org/forums/view ... 28&t=58151
by Burngate
Sat Aug 31, 2019 8:59 am
Forum: Other projects
Topic: Pushbutton multiple inputs
Replies: 12
Views: 508

Re: Pushbutton multiple inputs

by External Ground I mean the Ground for my Power supply for the Pi . Almost certainly, your power supply is what is known as "floating". That means there is no connection between its input and its output - if you were to use a multimeter to measure the resistance between either of the output wires...
by Burngate
Fri Aug 30, 2019 5:52 pm
Forum: Other projects
Topic: Pushbutton multiple inputs
Replies: 12
Views: 508

Re: Pushbutton multiple inputs

What, precisely, do you mean by "External Ground"? If you mean the pin labeled Earth on your mains supply (or some soil outside your house, which ought to be similar) then it may be at a very different voltage from the pin labeled GND on your Pi. The idea behind the pull-down resistor is to make sur...
by Burngate
Fri Aug 30, 2019 10:53 am
Forum: Troubleshooting
Topic: PI 4 PWR Led Flashing no boot, STICKY: Is your Pi not booting? Read throughugh
Replies: 9
Views: 341

Re: PI 4 PWR Led Flashing no boot, STICKY: Is your Pi not booting? Read throughugh

With nothing but the power supply connected, and no SD card, the green LED should blink four times then repeat.
The red LED SHOULD NOT BLINK

If it does, then you have a faulty power supply or faulty Pi.
by Burngate
Fri Aug 30, 2019 9:32 am
Forum: Troubleshooting
Topic: Pi 3 Model B USB not working
Replies: 1
Views: 157

Re: Pi 3 Model B USB not working

Several things come to mind, though how helpful you'll find them I don't know - probably not at all! Finding short-circuits can be difficult, in part because the resistances involved are similar to the resistances between your meter probes and the copper traces. You measured 0.6Ω across C97, and tha...
by Burngate
Wed Aug 28, 2019 10:29 am
Forum: Troubleshooting
Topic: Problems with Pi 4 Wiring Pi4 GPIO
Replies: 14
Views: 475

Re: Problems with Pi 4 Wiring Pi4 GPIO

... Here is my (non-working) code: #include <wiringPi.h> ... wiringPiSetup (); pinMode (18, OUTPUT); ... ... Please note. I have varied the pin number from 1 to 18, just to make sure I am not make a mistake with pin numbering. When the Pi first saw light of day, the wiringPi numbering system was em...
by Burngate
Wed Aug 28, 2019 9:57 am
Forum: Troubleshooting
Topic: Scale stops working when running 5v pump
Replies: 9
Views: 291

Re: Scale stops working when running 5v pump

Do we have any details about the Scale?
- how is it powered?
- how is it being read?
by Burngate
Wed Aug 28, 2019 9:23 am
Forum: Automation, sensing and robotics
Topic: Motor Sensing Circuit help
Replies: 5
Views: 451

Re: Motor Sensing Circuit help

Does your motor take the full 15A this CT can handle, when it's running? I would guess not, since I would not want to design anything without a bit of headroom, for safety. If it takes rather less than 15A, then the CT will give less than 1v. A single NPN transistor as described needs 0.6 - 0.7v on ...
by Burngate
Sat Aug 24, 2019 10:11 am
Forum: General discussion
Topic: Does the foundation produce the Zero under cost?
Replies: 12
Views: 688

Re: Does the foundation produce the Zero under cost?

My take on it: When the Pi first saw the light of day, it was meant to be as cheap as a computer could be and still be a computer. But things moved on, so someone asked (during tea-break, not proper working hours) "how cheap can a computer really be?" and the result was the Zero. I don't believe it...
by Burngate
Fri Aug 23, 2019 5:37 pm
Forum: HATs and other add-ons
Topic: Can I use a vending machine coin acceptor for the Pi Zero?
Replies: 5
Views: 508

Re: Can I use a vending machine coin acceptor for the Pi Zero?

If it's anything like ones I've seen, it may be just a bunch of switches, with no power supply or electronics.
If so, it's just a bunch of switches - use them as you wish.
by Burngate
Fri Aug 23, 2019 5:33 pm
Forum: Troubleshooting
Topic: GPIO Input Pin Voltages
Replies: 3
Views: 112

Re: GPIO Input Pin Voltages

I am not turning any of the internal pullup resistors on and I assume they are not on by default when a GPIO is configured as an input. Actually, they are - the first nine (0 - 8) are pulled up by default; the rest are pulled down. Ohm's law - GPIO 13 has 50k pull-down, you've provided 4k7 pull-up ...
by Burngate
Fri Aug 23, 2019 10:19 am
Forum: Off topic discussion
Topic: Best Raspberry Pi Alternatives 2019
Replies: 62
Views: 5216

Re: Best Raspberry Pi Alternatives 2019

When all is said and done, Dr. Upton is a nice guy. He's also a clever guy. Not many have both. The guy who came to fix my guttering is a nice guy, but he's not clever. If he had been, and if a neighbour hadn't called in the Authorities, he'd maybe have got several grand out of me, mug that I am. I...
by Burngate
Fri Aug 23, 2019 9:16 am
Forum: Off topic discussion
Topic: Solder Question
Replies: 13
Views: 1636

Re: Solder Question

Traditional electronic solder has several cores of rosin (or similar) flux to aid wetting and removing oxides. Although the company is called "Multicore", this solder is solid - no cores. Not knowing where you work, I have no idea what your company (or someone in it) was thinking about doing, but .....
by Burngate
Thu Aug 22, 2019 6:22 pm
Forum: General discussion
Topic: Newbie question! Noobs or etcher?
Replies: 8
Views: 371

Re: Newbie question! Noobs or etcher?

It's a question of History. In the beginning, it was thought rather difficult for a beginner to use Windows tools to load an SD card, so Noobs was invented as an easy and economical method to have more than one OS. Think quil pen v. hammer and chisel. But the cards rapidly grew to a size that meant ...
by Burngate
Thu Aug 22, 2019 5:18 pm
Forum: Troubleshooting
Topic: RPi 2 B+ reboots on USB drive connect
Replies: 14
Views: 312

Re: RPi 1 reboots on USB drive connect

That does explain the problem with disconnection, though, unlike everyone else's explanation.
After all, where can the current that's already flowing go when you disconnect the drive?
by Burngate
Wed Aug 21, 2019 10:39 am
Forum: General discussion
Topic: 12 v for driving electromagnets PCA9685
Replies: 31
Views: 1234

Re: 12 v for driving electromagnets PCA9685

I'm not sure about how to calculate the maximim current and the inductance on the coil. Sorry ... Calculating the inductance of electromagnets you've wound yourself ... could be difficult! But having wound them, you may be able to measure it. The same goes for the maximum current. But the maximum c...

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