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by rpdom
Wed Jun 03, 2020 6:00 pm
Forum: Beginners
Topic: Monitor GPIO inputs
Replies: 20
Views: 615

Re: Monitor GPIO inputs

The best Magazines in them days was called EVERY DAY ELECTRONICS My loft is full of them You could buy a pack of 555s for a pound :D don't get me started on that (not this topic anyway). Wireless World? It was Practical Electronics for me. I wonder how big a "pack" of 555s was? I can buy 10 for 99p...
by rpdom
Wed Jun 03, 2020 3:37 pm
Forum: Troubleshooting
Topic: Raspberry pi 4B fan is too loud.
Replies: 11
Views: 404

Re: Raspberry pi 4B fan is too loud.

The Forward Voltage is the voltage that gets dropped by the diode. It tends to be around 0.7V for most standard diodes.

So, yes. if you put two diodes in series you will get a drop of around 1.4V.
by rpdom
Wed Jun 03, 2020 3:30 pm
Forum: Beginners
Topic: What are the actions that perform read/write on SD card?
Replies: 5
Views: 203

Re: What are the actions that perform read/write on SD card?

The contents of the variables are stored in RAM.[*]

The SD card is read and written to on any File based operations.

[*] If you run out of RAM some of the contents will be moved from RAM to the swap file on the SD card instead. If this happens you will notice your Pi starts to run very slowly.
by rpdom
Wed Jun 03, 2020 5:48 am
Forum: General discussion
Topic: Composite video + headphones?
Replies: 4
Views: 177

Re: Composite video + headphones?

The only trouble, then, is that I'm not sure what I need to do to still be able to use headphones after that. I'm assuming the composite jack will do audio as well as video, but it seems like I'd need to find some kind of converter, to bridge the audio cables and the headphones. I'm also not sure t...
by rpdom
Wed Jun 03, 2020 5:25 am
Forum: Raspberry Pi OS
Topic: Repository seems corrupt
Replies: 3
Views: 131

Re: Repository seems corrupt

trejan is correct, the file you received is too small. How much free space have you got?
by rpdom
Wed Jun 03, 2020 5:13 am
Forum: General discussion
Topic: FLOATING POINT
Replies: 44
Views: 1330

Re: FLOATING POINT

Aarch64 has no MUL instruction! MUL is an alias for MADD (multiply-add) where the addend is the zero register. Reminiscent of the fastest way to do an unconditional branch in Compass on a CDC 640: BE B0,B0,<address> (Branch equal comparing register B0 to itself. Very fast because B0 always had a va...
by rpdom
Tue Jun 02, 2020 7:35 pm
Forum: Troubleshooting
Topic: Can't set up Pi Zero in headless mode!
Replies: 15
Views: 333

Re: Can't set up Pi Zero in headless mode!

Sorry, no I've never got around to trying it. All my zeroes either use USB ethernet adaptors or have wireless.
by rpdom
Tue Jun 02, 2020 7:25 pm
Forum: General discussion
Topic: Dead RPI 0
Replies: 12
Views: 405

Re: Dead RPI 0

Yes, that's the one. BCM stands for BroadCoM. That means your Pi Zero is working.
by rpdom
Tue Jun 02, 2020 7:19 pm
Forum: Troubleshooting
Topic: Can't set up Pi Zero in headless mode!
Replies: 15
Views: 333

Re: Can't set up Pi Zero in headless mode!

Just scanning your post - if it's a PiZero (NOT W), how are you expecting to connect it to your network? Am I missing something obvious here, or are you?? :) You need to add either: - a USB-to-wired Ethernet dongle, and an Ethernet patch cable to your router, or - a USB-wifi dongle (in which case t...
by rpdom
Tue Jun 02, 2020 4:57 pm
Forum: Troubleshooting
Topic: Zero W also resets during boot
Replies: 5
Views: 62

Re: Zero W resets during boot

Is there a way to re-programm the EEPROM No, because there is no EEPROM on a Pi Zero. The EEPROM updater will run, see that it isn't a Pi 4 (the only model with an EEPROM so far) and do nothing. You have some other problem. Does this happen with a freshly written image with no updates? with an old ...
by rpdom
Tue Jun 02, 2020 3:42 pm
Forum: General discussion
Topic: Dead RPI 0
Replies: 12
Views: 405

Re: Dead RPI 0

I measured 3.3volts directly from the micro usb connector on the rpi, one of the pads gave 3.3volts while the other 2volts which is why I assumed something to do with 5v supply being damaged Where exactly are you measuring these voltages? Is it the round pads underneath the connector marked USB? If...
by rpdom
Tue Jun 02, 2020 1:29 pm
Forum: Networking and servers
Topic: Raspberry Pi 1 as NAS?
Replies: 15
Views: 420

Re: Raspberry Pi 1 as NAS?

thagrol wrote:
Tue Jun 02, 2020 1:16 pm
I don't have the docs to hand but I think the current limit on a 1B may be lower.
The original 1B had 140mA fuses on each USB port. The later revisions replaced those with links and then got rid of them completely.

The B+ had the 600mA total default and could be configured to 1200mA.
by rpdom
Tue Jun 02, 2020 10:49 am
Forum: General discussion
Topic: Raspberry Pi - Hardware probes
Replies: 1
Views: 164

Re: Raspberry Pi - Hardware probes

Unlikely.
by rpdom
Tue Jun 02, 2020 10:45 am
Forum: C/C++
Topic: Can anybody help me troubleshoot an "if" statement?
Replies: 39
Views: 1064

Re: Can anybody help me troubleshoot an "if" statement?

How about pasting the actual code you are using. There are so many typos in those listings that it would never compile. Examples: printf (“Hello, what’s your name?\n); Missing " after \n printf (“Hi %s”, mane); mane? Printf (“, how are you today?\n); Capital "P" on printf, missing quote after \n. Th...
by rpdom
Tue Jun 02, 2020 8:33 am
Forum: General discussion
Topic: FLOATING POINT
Replies: 44
Views: 1330

Re: FLOATING POINT

It does show signs of being a progression in homework assignments. It does, and if it was me needing an answer I would do a web serach for ARM instruction manual (or something like that) and then find the ARM ARM for the version of ARM that the QEMU I was told to use is supporting and read up on wh...
by rpdom
Tue Jun 02, 2020 5:46 am
Forum: Other programming languages
Topic: Using netcat output in a bash if statement
Replies: 2
Views: 158

Re: Using netcat output in a bash if statement

That was quick work, congratulations! :)

I have a similar setup, but my code is written in C (not one of my main programming languages). It works well :)
by rpdom
Tue Jun 02, 2020 5:37 am
Forum: Troubleshooting
Topic: can't download files
Replies: 4
Views: 133

Re: can't download files

W. H. Heydt wrote:
Tue Jun 02, 2020 5:26 am
In addition to the issues mentioned about, you have an attempt to ssh into the system you are already ssh'd into. Not sure what you think that would accomplish....
It's to test that the local ssh server is working correctly.
by rpdom
Tue Jun 02, 2020 5:07 am
Forum: Troubleshooting
Topic: can't download files
Replies: 4
Views: 133

Re: can't download files

You're not following the instructions, you're just copy/pasting the text from the page which is showing example commands in use. The "$" at the frnt of the line is the command prompt. You already have that in your "[email protected]:~ $" prompt, and as DirkS has already said, you've got some HTML "<br>...
by rpdom
Tue Jun 02, 2020 5:02 am
Forum: General discussion
Topic: FLOATING POINT
Replies: 44
Views: 1330

Re: FLOATING POINT

Is there even a Raspberry Pi or Raspberry Pi OS involved here?
by rpdom
Mon Jun 01, 2020 8:32 pm
Forum: General discussion
Topic: How do I properly eject a USB SD Card adapter?
Replies: 13
Views: 484

Re: How do I properly eject a USB SD Card adapter?

There should be an "eject" symbol (Triangle with a line under it) on the right of the Task Bar at the top of the screen. Click on that.
by rpdom
Mon Jun 01, 2020 5:05 pm
Forum: Networking and servers
Topic: Extremely slow SMB xfer speeds from Win10 -> Raspi
Replies: 5
Views: 221

Re: Extremely slow SMB xfer speeds from Win10 -> Raspi

The windows machine will see a CIFS/SMB network share. The underlying filesystem on the Pi is not important on that respect. I have a Pi with a shared area that is on an ext4 formatted partition and my wife's Win10 laptop can access it without any trouble.
by rpdom
Mon Jun 01, 2020 6:40 am
Forum: Beginners
Topic: What is /dev/mmcblk0p2 ?
Replies: 7
Views: 8324

Re: What is /dev/mmcblk0p2 ?

This is a very old thread you've replied to. It might have been better to start a new one. However, those "disks" are partitions on your SD card. They do actually start at one, but the first few aren't being used by your Pi at the moment. They are the NOOBS (I assume) partitions and only used during...
by rpdom
Mon Jun 01, 2020 6:23 am
Forum: Automation, sensing and robotics
Topic: Trigger relay with 24V source
Replies: 9
Views: 331

Re: Trigger relay with 24V source

PCMANbob, does the normally closed pin need to go to ground? Or just leave it disconnected? I originally had it connected to ground. Just making sure. :-) Definitely leave it disconnected. If you connect it to ground in that diagram you will be shorting 3V3 to 0V when the relay is off, and possibly...
by rpdom
Mon Jun 01, 2020 6:19 am
Forum: Networking and servers
Topic: Extremely slow SMB xfer speeds from Win10 -> Raspi
Replies: 5
Views: 221

Re: Extremely slow SMB xfer speeds from Win10 -> Raspi

Using NTFS on the Pi is not a good idea. You'd be better off using ext4 for speed, as long as you don't need to disconnect the drive from the Pi and connect it to a Windows system.
The NTFS driver in Linux is not known for its speed.
by rpdom
Sun May 31, 2020 2:39 pm
Forum: Graphics, sound and multimedia
Topic: Looking for a 26-pin stereo AMP HAT
Replies: 12
Views: 403

Re: Looking for a 26-pin stereo AMP HAT

Technically there have never been any 26 pin HATs as the HAT standard requires 40 pins. However, pedantry aside ;-) I don't know of any boards that will do that. I think the I2S ones required the extra pins on the 1B rev2 to access the necessary gpios. As an alternative, if you aren't after super hi...

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