4 votes
Accepted

Why did Pi-4's port layout change?

According to the launch announcement it was to simplify routing: Our Gigabit Ethernet magjack has moved to the top right of the board, from the bottom right, greatly simplifying PCB routing. https://...
  • 6,381
4 votes
Accepted

Erratic GPIO event callback

Perhaps it is EMF from something switched on at around 18:00. I suggest you run monitor.py in the background and check its view of the situation. sudo pigpiod python monitor.py 13 If you see ...
  • 67.9k
3 votes

Make case fans work RaspberryPi4

Some fans supplied with cases are designed to run full-time. If that's what you're doing, you don't need any software - just connect the fan wiring to the appropriate GPIO pins. If you're asking how ...
  • 18.8k
3 votes

Board getting super hot, what's wrong with my Raspberry Pi 3?

Untouchably hot is not good unless you are really sensitive ;) Unfortunately I think it implies damaged hardware. I found that the heating issue only presented itself when the sd card contains a ...
  • 56.5k
2 votes

Children: Concerned with lead and other substances in handling a Raspberry Pi without case?

Common sense would be that children who are too young to understand or be responsible for the issues involved with handling a bare board should be closely supervised (or just plain told they are too ...
  • 56.5k
2 votes

I too have knocked off a component from the underside of my Pi 4 board. HELP

There are no schematics published for the Raspberry Pi. Only reduced schematics are available, which show connectors and parts of the power distribution circuit. You won't find that resistor in there. ...
2 votes

RPi can't boot up from battery, needs to be connected to usb-c then while the battery is connected disconnect power supply usb-c

it draws 500 milliamps as per specification If you mean the Pi 4, you are referring to a minimum that it draws while idle. Electronic gadgets, especially computers, do not draw a steady fixed amount ...
  • 56.5k
2 votes

RPi can't boot up from battery, needs to be connected to usb-c then while the battery is connected disconnect power supply usb-c

The Pi4 needs more than 500mA to boot. It probably needs at least an amp. Once booted it can presumably idle at 500mA.
  • 67.9k
2 votes
Accepted

Board getting super hot, what's wrong with my Raspberry Pi 3?

So after some digging around, I found a YouTube video, How to fix a Raspberry Pi 3 where the wifi chip is overheating, where the person described my problem pretty closely, and looking at the comments ...
2 votes
Accepted

Raspberry Pi 3B+ board SMT component identification

I admire what you are doing, that is how I learned. What you learn this way will stick a very long time. Try this link: https://www.etechnophiles.com/wp-content/uploads/2020/12/Parts-of-R-Pi-3B.jpg It ...
  • 925
2 votes
Accepted

How to control existing button with a Raspberry Pi?

What you need to do first, is to check what is the voltage between the contacts which button closes. Second you need to check how much current will go through the button when it is closed. To do so, ...
  • 196
1 vote
Accepted

Rpi Pico receiving on multiple UARTs

There are only two UARTS on the Pico. They are identified as the channel 0 UART and the channel 1 UART. For convenience each UART is routed to multiple GPIO. See the table I give at https://abyz.me....
  • 67.9k
1 vote
Accepted

What is the byte content of Raspberry Active Source hdmi-cec message?

After more digging, I finally found a solution to my specific problem. For my setup, as described in my question, one can turn on the Harman Kardon AVR 156 by broadcasting an active source message ...
1 vote

weird @^ in log files

^@ is the ASCII NULL character in caret notation. Generally means a bit of garbage in the log file. Nothing I would be worried about https://en.wikipedia.org/wiki/Caret_notation
  • 3,372
1 vote

LPM raspberry pi 4B extinction mechanism

My question: by which signal / pin, the processor sends the order to the PMIC to turn off the regulated outputs? In section 2B of the RPi 4B schematic, you will see a connection to GLOBAL_RESET. This ...
  • 18.8k
1 vote
Accepted

Raspberry PI B schematics and hw drawings

The Schematics and Mechanical Drawings of most models are available. The Pi Model B did have a reasonably "complete" 5 page schematic (Raspberry-Pi-Schematics-R1.0.pdf), but does not seem to ...
  • 54.8k
1 vote

Raspberry PI B schematics and hw drawings

The information you seek should be at https://www.raspberrypi.com/documentation/computers/raspberry-pi.html To determine the version of a pi is simple if you have a running linux on it; see https://...
  • 2,311
1 vote

RPi4 Broken Resistor

What I would consider is purchasing another Pi, removing and measuring the value of that resistor. Then purchase new resistors and install one on each board. If you do not have the skill set to do the ...
  • 925
1 vote

RPi4 Broken Resistor

Unfortunately, the RPi conglomerate does not publish full schematics, or a parts list. Consequently, unless the part you are interested in is covered on their partial schematics, you will have to ...
  • 18.8k
1 vote

What sensor can I use for detecting a metal type without the use of magnets?

The simplest of-the-shelf device to do this would probably be a low-resistance meter, using 4-terminal sensing. You could probably create your own version, but the design would be quite tricky, as the ...
  • 272
1 vote
Accepted

Can I add a second processor to pi 4b 8gb? Is it even possible?

It would be extremely difficult if not impossible. There is no provision on the Pi 4b board for a second chip, and the hardware isn't designed to support a second chip. One reasonable approach to ...
  • 794
1 vote
Accepted

Canakit fan that came with raspberry pi 4 louder then usual

That is s strong indication that it is starting to die assuming nothing has moved. Generally it is caused by the lubrication on the berings drying out. Mechanical things that move will fail, we just ...
  • 925
1 vote

Desolder wifi/bluetooth module on a Raspberry Pi 4

I desoldered the wifi chip with hot air gun and Rpi seems to be working just fine. Also disabled wifi and BT in /boot/config.txt (maybe not necessary).
  • 11
1 vote

How to install a Kuman 7" Touchscreen with Raspberry Pi

Note that matchbox is a standard software which can be installed from the Pi OS repository using apt-get install matchbox-keyboard.
1 vote

Second WiFi adapter for the Raspberry Pi 4 B

We are successfully using a TP-Link TL-WN722N (Realtek chipset, i.e. v2 or v3) adapter with a Raspberry Pi Zero W running balenaOS 2.54. It was completely plug-and-play; no drivers necessary.
  • 111

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