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by Burngate
Fri Nov 19, 2021 6:41 pm
Forum: Beginners
Topic: Trying to understand GPIO.
Replies: 7
Views: 423

Re: Trying to understand GPIO.

The reasoning behind "active low" lies in part way back in history when logic chips were first invented. Leaving a 7400 gate input unconnected was equivalent to pulling it high, with no current flowing into the gate. To pull it low required pulling quite a large current by modern standards...
by Burngate
Sat Nov 13, 2021 10:36 am
Forum: Automation, sensing and robotics
Topic: Create an Amplitude modulated signal
Replies: 5
Views: 281

Re: Create an Amplitude modulated signal

Are you perhaps wanting to generate a 50Hz / 60Hz sine-wave, with amplitude up to 24v, set by your "digital signal"? If so, then hardware-wise, I would treat it as an audio signal. So pwm, into an op-amp then a power amp. Software-wise, Python should be able to control the Pi's pwm system....
by Burngate
Fri Nov 05, 2021 10:35 am
Forum: Off topic discussion
Topic: Just out of curiosity...
Replies: 11
Views: 575

Re: Just out of curiosity...

Spam or not (the English isn't as good as one would expect) if it stays, shouldn't it be in "For Sale" rather than "Off Topic"?
by Burngate
Mon Nov 01, 2021 11:06 am
Forum: General discussion
Topic: Quick question, can i use this charger to power Pi 3b+ ?
Replies: 26
Views: 884

Re: Quick question, can i use this charger to power Pi 3b+ ?

It says Output DC: 3.6V-6.5V=3A, i've read somewhere that " USB 3 power delivery and Qualcomm Quick Charge ports default to 5V output, other voltages must be actively negotiated. RPi 3 doesn't support such negotiation protocols, so the voltage will stay at 5V. " As far as I'm aware, 6.5V ...
by Burngate
Mon Nov 01, 2021 11:00 am
Forum: Beginners
Topic: Convert 0 to 5V (analog) to 0 to ±5V (analog)
Replies: 7
Views: 308

Re: Convert 0 to 5V (analog) to 0 to ±5V (analog)

I would like to convert 0 to 5V (analog) to 0 to ±5V (10V with 5V GND analog output) as shown in the attached image, what is the general way to do this? Is there a component that can do this? How fast is the analogue signal changing? If it's an audio signal, an op-amp would be relatively easy, but ...
by Burngate
Tue Oct 19, 2021 9:14 am
Forum: General discussion
Topic: Do we love the 40-pin header? Is there something more desireable?
Replies: 33
Views: 1467

Re: Do we love the 40-pin header? Is there something more desireable?

Some IDE cables (probably the older ones) are basically 40-way ribbon cable with a connector crimped to each end. They are OK. Other cables (the newer ones?) have 40 signal cores with ground cables in between, so they are actually 80-core cables. Those are NOT OK. They can be identified by a fairly...
by Burngate
Fri Oct 15, 2021 10:04 am
Forum: Troubleshooting
Topic: GPIO stuck on/off issue
Replies: 7
Views: 336

Re: GPIO stuck on/off issue

It's difficult to see, but the little of your Pi we can see seems to show the display connector and the SD slot under the ribbon. If that's so, and the ribbon isn't twisted, then pin 1 - 3v3 - arrives at the breadboard at the top, where your "breakout board" is labelled as GPIO 21 TLDR, tw...
by Burngate
Sun Oct 10, 2021 9:46 am
Forum: Beginners
Topic: Is it possible to have serial and I2C buses Raspberry Pi 4 Model B?
Replies: 3
Views: 207

Re: Is it possible to have serial and I2C buses Raspberry Pi 4 Model B?

Your previous (unanswered) question viewtopic.php?f=44&t=321234 also mentioned 10 more GPIOs.
For best results it might be worth looking on https://pinout.xyz/

The camera input will not take up GPIOs, and nor will the HDMI output
by Burngate
Fri Oct 08, 2021 6:17 pm
Forum: General discussion
Topic: Feedback on website split
Replies: 92
Views: 4749

Re: Feedback on website split

I often have to re-login to some sites, they don't feel the need to apologise to me for the very minor inconvenience and I don't feel the need to be apologised to either. Re-logging in to the forums took me about 2 minutes to dig up the old password. And that was it. Everything else just works. For...
by Burngate
Fri Oct 08, 2021 10:25 am
Forum: General discussion
Topic: Feedback on website split
Replies: 92
Views: 4749

Re: Feedback on website split

When my laptop wouldn't let me log in, I assumed Firefox had thrown a wobbly and lost all my passwords. That was "confirmed" when the password on the paper backup worked, so I was preparing to re-enter all the passwords for all the other sites as well. Just nice to know it wasn't a my-end ...
by Burngate
Sat Sep 25, 2021 5:41 pm
Forum: Python
Topic: what's wrong ?
Replies: 4
Views: 594

Re: what's wrong ?

Deleted
by Burngate
Thu Sep 23, 2021 9:35 am
Forum: Off topic discussion
Topic: Car chip shortage, and RP 2040?
Replies: 43
Views: 2703

Re: Car chip shortage, and RP 2040?

The thing I'd like to see would standardization in the hardware. There is no need for each and every make and model to have a different--physical--MCU. It's so bad that at least one manufacturer has different part numbers depending on whether the vehicle has a standard transmission or an automatic,...
by Burngate
Sat Sep 18, 2021 9:06 am
Forum: General discussion
Topic: Difference Raspberry Pi 4 vs 4B
Replies: 7
Views: 468

Re: Difference Raspberry Pi 4 vs 4B

There's only the Pi 4B. Whoever lists a Pi 4 means Pi 4B.

Many years ago, you could get a Pi A, which was a cut-down Pi B, but now there isn't a cut-down 4B

Of course you can now get the Pi 400, which is effectively a Pi 4B with bells & whistles.
by Burngate
Mon Sep 13, 2021 5:30 pm
Forum: Troubleshooting
Topic: Low Voltage Warning - New Pi
Replies: 3
Views: 355

Re: Low Voltage Warning - New Pi

... but when I run vcgencmd measure_volts it tells me the volt is only 0.8700V. Is this normal, even under load? The voltage measured by "vcgencmd measure_volts" is one of several inside the SoC, and has little to do with the in-coming nominal 5v monitored by the PMIC to produce the low-v...
by Burngate
Wed Sep 08, 2021 8:02 am
Forum: Troubleshooting
Topic: Problem with OS and SD cards
Replies: 2
Views: 194

Re: Problem with OS and SD cards

... I formatted my SD card, I unzipped the file and put the contents into a new folder and put it in my 32 GB SD card ... Sorry - that's the wrong way to do it! What you need to do is described in https://projects.raspberrypi.org/en/projects/raspberry-pi-setting-up/2 I'm not convinced that the &quo...
by Burngate
Mon Sep 06, 2021 9:04 am
Forum: General discussion
Topic: 12v fan control with built-in cooling fan control in raspbian os
Replies: 8
Views: 1370

Re: 12v fan control with built-in cooling fan control in raspbian os

Well, I want you to use a translator. 저는 12v Noctua Fan을 가지고있습니다 최근에 나는 Raspbian Os에 CoolingFan 제어 기능이 있다는걸 알았습니다 나는 그 기능으로 내 Fan을 동작시키고 싶습니다 누가 나를 도와줘 5v팬을 사고싶지 않습니다 나는 현재 2N2222트랜지스터와 1KOhm저항, 그리고 다이오드 등을 가지고 있습니다 이것들로 조립하는 방법 등을 알려주세요 미리 감사드립니다 :D Is this any help? Mae gen i Fan Noctua 12v Yn dd...
by Burngate
Fri Sep 03, 2021 5:09 pm
Forum: General discussion
Topic: Raspberry Pi not working!
Replies: 3
Views: 308

Re: Raspberry Pi not working!

Have you looked at the sticky at viewtopic.php?f=28&t=58151?
by Burngate
Fri Aug 20, 2021 8:56 am
Forum: General
Topic: PWM audio amplifier
Replies: 7
Views: 637

Re: PWM audio amplifier

You could perhaps use an H-bridge - that's what the output stage of a class D amplifier really is - so eliminating the analogue-PWM stage of the PAM8302.
by Burngate
Thu Aug 12, 2021 8:53 am
Forum: Off topic discussion
Topic: What was your first computer?
Replies: 598
Views: 257411

Re: What was your first computer?

It could also mean that there could be someone, owning and using a Pi and asking questions here, is younger than the first Pi
by Burngate
Thu Aug 05, 2021 6:05 pm
Forum: Advanced users
Topic: Will Pi 4 likely get too hot in enclosure?
Replies: 9
Views: 882

Re: Will Pi 4 likely get to hot in enclosure?

... PVC 6"x6"x4" sealed waterproof enclosure ... large case with fan from same vendor Be aware that, since the Pi needs at least a power cable to reach it, and that needs a hole in the enclosure, it may not now be "sealed waterproof" Also, the Pi itself may be capable of sl...
by Burngate
Wed Aug 04, 2021 9:27 am
Forum: Python
Topic: GPIO goes to 2.5v
Replies: 6
Views: 480

Re: GPIO goes to 2.5v

Sorry, I had hoped that this was a common / known situation. I will do more investigation to see what the cause is and (assuming I figure it out) then post an update. No! No! No! - Common problems are boring! People here like an odd one to get the brain going, and make them feel useful! So do show ...
by Burngate
Sat Jul 31, 2021 5:11 pm
Forum: Troubleshooting
Topic: SDA reads 5v
Replies: 6
Views: 439

Re: SDA reads 5v

Brill!
by Burngate
Fri Jul 30, 2021 5:38 pm
Forum: Troubleshooting
Topic: SDA reads 5v
Replies: 6
Views: 439

Re: SDA reads 5v

.. the SDA pin (GPIO2) measures 5v on the Zero but 3.3v on the Pi3. It is still 5v even with nothing connected to that pin. It shouldn't be 5v - no GPIO should be at 5v, and if it's fed 5v it will be broken. Not only that, but both GPIOs 2 & 3 have 1k8 pulll-ups to 3v3, so if GPIO2 is at 5v, th...
by Burngate
Tue Jul 27, 2021 5:23 pm
Forum: Beginners
Topic: Shutting Pi Down - LEDs and Best Command
Replies: 9
Views: 581

Re: Shutting Pi Down - LEDs and Best Command

davidcoton wrote:
Tue Jul 27, 2021 10:05 am
I haven't checked, but on shutdown the 3V3 supply is off, so all GPIO pins will appear low, and may therefore sink a small current through the default pull-up or pull-down.
Doesn't the pull-up or -down require a fet to be on, which would require the 3v3 to be present?
by Burngate
Thu Jul 15, 2021 8:44 am
Forum: Off topic discussion
Topic: Toms Hardware / Eben Upton / Pi Cast
Replies: 21
Views: 1617

Re: Toms Hardware / Eben Upton / Pi Cast

Some other sites I visit have been fortunate in having people willing to transcribe what's been said into text - a bit like what's supposed to happen in courts. I couldn't do it myself - not enough patience, can't do shorthand (does that get taught in schools these days, or is it considered too un-w...

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