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by rpdom
Sun May 27, 2018 6:37 am
Forum: Troubleshooting
Topic: mount.nfs: requested NFS version or transport protocol is not supported
Replies: 5
Views: 102

Re: mount.nfs: requested NFS version or transport protocol is not supported

That sounds like the portmapper service isn't running on the Pi. What does "systemctl status rpcbind" show?
by rpdom
Sat May 26, 2018 5:19 pm
Forum: General discussion
Topic: How much space does Raspbian actually take ??
Replies: 2
Views: 144

Re: How much space does Raspbian actually take ??

Generally, df -h / will return the used space (minus the tiny boot partition). On some of my headless Raspbian Stretch Lite systems I get these values: Filesystem Size Used Avail Use% Mounted on /dev/root 9.9G 1.9G 7.5G 20% / Filesystem Size Used Avail Use% Mounted on /dev/root 15G 1.4G 13G 10% / Us...
by rpdom
Thu May 24, 2018 8:10 pm
Forum: Beginners
Topic: Parallel or multi-tasking functionality
Replies: 4
Views: 126

Re: Parallel or multi-tasking functionality

A digital phone calls needs about 100 kbit/s in each direction. You are going to need a lot of simultaneous calls in progress before they become an issue in the network bandwidth arena. However, "CPU bandwidth" is a different matter as conversational audio does not like latency. So think about a de...
by rpdom
Thu May 24, 2018 7:43 pm
Forum: Beginners
Topic: Parallel or multi-tasking functionality
Replies: 4
Views: 126

Re: Parallel or multi-tasking functionality

I run more than half of those tasks on a Pi 2B with a 2TB USB disk. Not hugely fast, but it does work. My VPN server is a PI 1B. I don't have a digital phone or security camera system, but using an official PI camera doesn't take much CPU, it uses the GPU for most of the heavy lifting.
by rpdom
Wed May 23, 2018 6:54 am
Forum: Off topic discussion
Topic: Raspberry Pi 3 with 2GB RAM playing the devil's advocate
Replies: 83
Views: 36158

Re: Raspberry Pi 3 with 2GB RAM playing the devil's advocate

Nick_Hudson wrote:
Wed May 23, 2018 6:45 am
And I'm thinking to run SNES games on Raspberry Pi. :lol:
Retropi
by rpdom
Wed May 23, 2018 6:23 am
Forum: General discussion
Topic: Special-case power requirements
Replies: 11
Views: 335

Re: Special-case power requirements

"RF Kill Switch Status" is the point where the WiFi is being enabled. That will cause a sharp increase in the current used. It does sound like something to do with the wire or its connections.
by rpdom
Wed May 23, 2018 6:09 am
Forum: Beginners
Topic: Question about heatsinks
Replies: 8
Views: 217

Re: Question about heatsinks

Yes, feet for the bottom of the case. They peel off the backing paper easily and are self-adhesive.

As for the heatsinks, I'd put the largest one on top of the main chip, as it can help a bit, and ignore the others.
by rpdom
Wed May 23, 2018 4:45 am
Forum: Advanced users
Topic: Install adb newer than 1.0.31
Replies: 10
Views: 256

Re: Install adb newer than 1.0.31

The version of adb in Raspbian Stretch is 1.0.36
by rpdom
Wed May 23, 2018 4:38 am
Forum: General discussion
Topic: Installing PHP
Replies: 6
Views: 213

Re: Installing PHP

Run apt-get update again before doing the apt-get install command. This extra step is needed just once due to something that was changed in a recent upgrade.
by rpdom
Tue May 22, 2018 7:48 pm
Forum: Troubleshooting
Topic: /bin/tar gives Segmentation fault.
Replies: 7
Views: 185

Re: /bin/tar gives Segmentation fault.

I am currently using Model B Rev 2. Yes. Adding Debian packages to that one will break it. Is it possible to reinstall /bin/tar? If yes, how can I reinstall it? It is probably possible, if you can get hold of the right files and extract them manually, but there are likely to be more problems than j...
by rpdom
Tue May 22, 2018 7:22 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: help with a salvaged lcd
Replies: 1
Views: 90

Re: help with a salvaged lcd

Just because the connectors look the same doesn't mean they use the same wiring. (Hint: They don't). Some displays can be connected to the Pi if you can find a converter board that will drive them from HDMI. Others can be connected to the GPIO pins in DPI mode, but that will also require an interfac...
by rpdom
Tue May 22, 2018 6:27 pm
Forum: Troubleshooting
Topic: How are folder permissions changed?
Replies: 16
Views: 7974

Re: How are folder permissions changed?

If using samba, you could format the disk as ext4 and gain full Linux permissions and better performance (NTFS is slow on Linux)
by rpdom
Tue May 22, 2018 5:02 pm
Forum: Advanced users
Topic: Install adb newer than 1.0.31
Replies: 10
Views: 256

Re: Install adb newer than 1.0.31

The option of running "apt-get install adb" it's not possible because apt says there is no package called like that. There is such a package. pi@raspi1:~ $ sudo apt-get install adb Reading package lists... Done Building dependency tree Reading state information... Done The following additional pack...
by rpdom
Tue May 22, 2018 6:12 am
Forum: Troubleshooting
Topic: /bin/tar gives Segmentation fault.
Replies: 7
Views: 185

Re: /bin/tar gives Segmentation fault.

helenrai wrote:
Tue May 22, 2018 6:03 am
I had added Debian packages. After that this happens
Which Pi? Most Debian packages will not work on Pi 0/1.

With help you may be able to recover, but it will not be easy.
by rpdom
Tue May 22, 2018 5:42 am
Forum: Automation, sensing and robotics
Topic: Alarm voltage detection
Replies: 6
Views: 230

Re: Alarm voltage detection

Moe wrote:
Mon May 21, 2018 11:51 pm
OK, rubbish analogy :( sorry
Actually, I quite liked it. It has potential. ;-)
by rpdom
Tue May 22, 2018 5:25 am
Forum: General discussion
Topic: STICKY: PMs being turned off from June 13
Replies: 21
Views: 790

Re: STICKY: PMs being turned off from June 13

I'm confused, what about this law requires you to remove private messaging? The new rules are a bit vague, but they are about protecting individuals. The main issue here is that there is nothing that can reliably verify the age of a user on the forums. Anyone of any age can use them. This includes ...
by rpdom
Mon May 21, 2018 6:41 pm
Forum: Beginners
Topic: Using a shared resistor on different LEDS?
Replies: 4
Views: 128

Re: Using a shared resistor on different LEDS?

It is not recommended to use a shared resistor for multiple LEDs as the LEDs can vary in current consumption and some will get too much and other will not get enough.

Better to have one resistor per LED.
by rpdom
Sun May 20, 2018 3:39 am
Forum: Troubleshooting
Topic: Pi 3 is Destroying SD Cards
Replies: 34
Views: 6856

Re: Pi 3 is Destroying SD Cards

It is very possible that the heat was caused by a fault in the card. The card slot does not normally get hot, maybe a bit warm if anything. A very small number of people have reported cards getting very hot and failing - not just in Pi's, but in all sorts of other devices. Not just microSD cards, fu...
by rpdom
Sat May 19, 2018 6:28 pm
Forum: General discussion
Topic: Upgrade confusion?
Replies: 20
Views: 738

Re: Upgrade confusion?

Just one follow-on question: How does one know that a reboot is necessary to load the upgraded kernel? Is this (should it be) a routine part of the upgrade procedure? That is a very good question. I seem to remember upgrades on older Debian Linux systems used to give a message that a reboot was req...
by rpdom
Sat May 19, 2018 8:42 am
Forum: General discussion
Topic: Problem on MAX30105 sensor on Raspberry Pi 3
Replies: 14
Views: 402

Re: Problem on MAX30105 sensor on Raspberry Pi 3

Hi Lawson and rpdom, Thanks for your reply. It means that if I really supply the 5V to the sensor, the 5V will burn my SDA or SCL pins of raspberry pi? As long as the sensor doesn't have pull-ups to 5V on board (and most don't), you'll be OK. However, from the schematic it appears that board does h...
by rpdom
Sat May 19, 2018 8:05 am
Forum: General discussion
Topic: Problem on MAX30105 sensor on Raspberry Pi 3
Replies: 14
Views: 402

Re: Problem on MAX30105 sensor on Raspberry Pi 3

I have two I2C RTCs and a BMP180 temp sensor all running at 5V. I use 5V for MCP23017s. I haven't fried a RPi yet. So the pull-up on the open drain is 5V safe. That's got nothing to do with it. 5V never appears on the i2c lines, no matter what the other devices are powered at. They are NOT 5V SAFE!...
by rpdom
Sat May 19, 2018 7:29 am
Forum: General discussion
Topic: Problem on MAX30105 sensor on Raspberry Pi 3
Replies: 14
Views: 402

Re: Problem on MAX30105 sensor on Raspberry Pi 3

DougieLawson wrote:
Sat May 19, 2018 7:24 am
Because I2C is open drain.
That doesn't make it "5V safe" at all. Put 5V on it and it dies. If any device on the bus has pull-ups to 5V then you risk frying the GPIO.
by rpdom
Sat May 19, 2018 7:02 am
Forum: General discussion
Topic: Problem on MAX30105 sensor on Raspberry Pi 3
Replies: 14
Views: 402

Re: Problem on MAX30105 sensor on Raspberry Pi 3

DougieLawson wrote:
Sat May 19, 2018 6:47 am
The I2C interface on pin#3 & pin#5 has 1.8KOhm resistors so that it's 5V safe. The secondary interface on pin#27/pin#28 doesn't have that hardware so is NOT 5V safe.
How does a pull-up to 3.3V make the pins "5V safe"?
by rpdom
Sat May 19, 2018 5:50 am
Forum: Troubleshooting
Topic: Can't Get LED to light
Replies: 14
Views: 321

Re: Can't Get LED to light

The circuit looks good and the LED sounds like it is the right way around. If the LED doesn't light even when the connection is made to pin 1 (3.3V) instead of pin 11 (GPIO17), then the LED is dead, the resistor is wrong (that looks like a 390 Ohm to me, but that should work), or one of the wires is...
by rpdom
Sat May 19, 2018 5:16 am
Forum: Troubleshooting
Topic: Can't Get LED to light
Replies: 14
Views: 321

Re: Can't Get LED to light

You can upload small images (up to 64KB) as attachments and place inline with your post. Otherwise upload to an external site like imgur and post a link to the image.

I just noticed I forgot one other possibility: The LED could be the wrong way round. They don't work if connected backwards.

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