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by rpdom
Tue Jul 17, 2018 5:23 am
Forum: General discussion
Topic: Using Hard Drive with Raspberry Pi
Replies: 44
Views: 9041

Re: Using Hard Drive with Raspberry Pi

I tried taking the board out of the enclosure/300GB hard drive and put it on a 7200RPM hard drive that is supposed to have 320GB of data on it. On the sticker, it says it has 5VDC and 0.65A, then it says 12VDC 0.50A right under that. I'm guessing that means 5 volts, 0.65A direct current or 12 volts...
by rpdom
Mon Jul 16, 2018 8:07 pm
Forum: Troubleshooting
Topic: Pi 3B+ / Shorting 3.3V to GND
Replies: 14
Views: 285

Re: Pi 3B+ / Shorting 3.3V to GND

The chip doesn't need to melt, just a small amount of damage will be enough.
by rpdom
Mon Jul 16, 2018 4:46 am
Forum: Java
Topic: a quick performance comparison of java on raspbian
Replies: 39
Views: 31859

Re: a quick performance comparison of java on raspbian

They are the output from the "time" command shown by -rst-, which measures resources used by your code. You can put "time" in front of any command line to see what it uses. "real" is the actual time the process took to run. "user" is the amount of cpu time used for your user process. "sys" is the am...
by rpdom
Sun Jul 15, 2018 3:35 pm
Forum: Troubleshooting
Topic: File attachments
Replies: 6
Views: 100

Re: File attachments

Zip the file and attach that. Zip files are allowed.
by rpdom
Sun Jul 15, 2018 8:01 am
Forum: Troubleshooting
Topic: Raspberry pi 3 b+ won't boot with multiple SD cards
Replies: 7
Views: 135

Re: Raspberry pi 3 b+ won't boot with multiple SD cards

As you are using a 3B+, can you try putting one of the SD cards into a USB adaptor, plugging that in to the Pi (with no card in the usual slot) and see if that boots. If it does, it means that the SD card slot has been broken in some way, but you can still boot from USB. If it doesn't, it possibly m...
by rpdom
Sun Jul 15, 2018 7:56 am
Forum: Teaching and learning resources
Topic: Seeking help on curriculum design for kids
Replies: 11
Views: 217

Re: Seeking help on curriculum design for kids

Thank you for the Code Club site! The projects are so well designed and structured. We have been seeking curriculum for young girls especially at elementary school age (a high percentage of girl scouts are under 13). Code Club's projects are for 9-13, which are great resources. Four of our last lot...
by rpdom
Sun Jul 15, 2018 7:13 am
Forum: Networking and servers
Topic: Best choice of web server on Raspberry Pi
Replies: 5
Views: 198

Re: Best choice of web server on Raspberry Pi

I don't know where you get the idea that Apache is insecure.

I use Apache and nginx web servers.
by rpdom
Sun Jul 15, 2018 6:46 am
Forum: Teaching and learning resources
Topic: Seeking help on curriculum design for kids
Replies: 11
Views: 217

Re: Seeking help on curriculum design for kids

There's also the Code Club projects (now run by the RPF). All Code Clubs must register, but anyone is able to access and use the course material available. There are projects for Scratch, Python and HTML/CSS, along with some for the micro:bit, Sonic Pi and the Raspberry Pi and Sense Hat (with online...
by rpdom
Sat Jul 14, 2018 8:02 pm
Forum: General programming discussion
Topic: Question About Compiling RasPi Apps
Replies: 9
Views: 264

Re: Question About Compiling RasPi Apps

Build on a Pi 3B and move it to the Zeroes once complete.
by rpdom
Sat Jul 14, 2018 5:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADC for analog video (possible?)
Replies: 26
Views: 583

Re: ADC for analog video (possible?)

It does both. If you use raspivid to record a video it uses H264 hardware encoder to compress it. Sure, but that isn't going to be real-time, is it? The accelerator hardware can provide real-time decoding. Easily. I've use the omxtx program to hardware decode mpeg2 video and encode to H264 (mp4) at...
by rpdom
Sat Jul 14, 2018 7:04 am
Forum: Beginners
Topic: Connect USB device via GPIO pins?
Replies: 4
Views: 137

Re: Connect USB device via GPIO pins?

If you are really keen, and good at soldering/desoldering, you could remove one of the USB connector pairs and wire the device in to the holes.

You could break your Pi if you get it wrong.
by rpdom
Sat Jul 14, 2018 6:56 am
Forum: Python
Topic: extract variables from mariadb select
Replies: 2
Views: 74

Re: extract variables from mariadb select

Every time you use "cursor.fetchone()" it tries to read the next returned row from the query. Your query is only returning one row. The "Name = cursor.fetchone()[0]" line will read that result and extract the first element of it. The line "cellNumber = cursor.fetchone()[1]" will try and read another...
by rpdom
Sat Jul 14, 2018 4:13 am
Forum: General discussion
Topic: Unable to load dynamic library '/usr/lib/php/20151012/php_mysqli.dll
Replies: 9
Views: 223

Re: Unable to load dynamic library '/usr/lib/php/20151012/php_mysqli.dll

Comment out that extension line again. It is only used for PHP on Windows. It's not valid for Linux.

Then install the php-mysql package. That will provide the Linux mysqli extensions.

Code: Select all

sudo apt-get update
sudo apt-get -y install php-mysql
by rpdom
Fri Jul 13, 2018 9:17 pm
Forum: Beginners
Topic: HDMI problem
Replies: 6
Views: 166

Re: HDMI problem

The TVs and monitors I've used have had to be on, but it didn't matter about the input being selected. Presumably they would send the correct EDID to the Pi even though the input was not the active one.
by rpdom
Fri Jul 13, 2018 5:29 am
Forum: Off topic discussion
Topic: Connecting leads to a button/coin battery
Replies: 5
Views: 213

Re: Connecting leads to a button/coin battery

Clothes peg? Wrap a wire around each of the two ends. Clamp the cell between them.
by rpdom
Thu Jul 12, 2018 5:45 pm
Forum: Advanced users
Topic: Solar with RPi Zero v1.3
Replies: 11
Views: 265

Re: Solar with RPi Zero v1.3

Mickety wrote:
Thu Jul 12, 2018 5:31 pm
Tha'ts good, because I only use a WiFi USB dongle thingy and boot in CLI .
WiFi uses a lot of power. By using that you can add at least another 100mA or more (probably a lot more) to your calculations.
by rpdom
Thu Jul 12, 2018 3:37 pm
Forum: Beginners
Topic: updates and upgrades
Replies: 2
Views: 140

Re: updates and upgrades

I do an update and upgrade once a week. I very rarely reboot, most of the time it isn't needed. Only when something like the bootload or firmware gets an upgrade (raspberrypi-bootloader and raspberrypi-kernel packages).
by rpdom
Thu Jul 12, 2018 7:58 am
Forum: Beginners
Topic: UART (PL011) and mini UART
Replies: 3
Views: 120

Re: UART (PL011) and mini UART

The UARTS are available on GPIOs 14 and 15, which are on physical (Board) pins 8 and 10. You can only use one UART at a time on these pins.
by rpdom
Thu Jul 12, 2018 5:46 am
Forum: General discussion
Topic: Cluster for IP ProxyNeon
Replies: 4
Views: 213

Re: Message for IP ProxyNeon

While parallel processing may not feature prominently in the revised curriculum, it is my opinion that student competency in such topics is necessary for the Raspberry Pi to have the same relative impact that the BBC Micro did in the 80's. For this reason I appreciate every opportunity to discuss c...
by rpdom
Wed Jul 11, 2018 6:47 pm
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 835

Re: Controlling homemade solenoids using Rpi Z W

So we took a stupid risk and tried connecting the homemade solenoid to the pi without a resistor and surprisingly it didn't do anything. The 3 volt battery was able to move the pin so isn't the 3.3v gpio pin supposed to be enough? The gpio pin can't supply as much current as a battery can. It can o...
by rpdom
Wed Jul 11, 2018 6:45 pm
Forum: Advanced users
Topic: REAL MySQL instead of MariaDB
Replies: 32
Views: 7537

Re: REAL MySQL instead of MariaDB

phpmyadmin should still work, pretty much out of the box with a standard installation. I've got one running.
by rpdom
Wed Jul 11, 2018 6:44 pm
Forum: Advanced users
Topic: REAL MySQL instead of MariaDB
Replies: 32
Views: 7537

Re: REAL MySQL instead of MariaDB

DougieLawson wrote:
Wed Jul 11, 2018 4:02 pm
php7.0 only supports MySQLi (the old connector was dropped).
Or the PDO extension.
by rpdom
Wed Jul 11, 2018 6:38 pm
Forum: Networking and servers
Topic: Make FTP server available outside of home network (Do I have everything I need?)
Replies: 11
Views: 242

Re: Make FTP server available outside of home network (Do I have everything I need?)

tpyo kingg wrote:
Wed Jul 11, 2018 5:43 pm
rpdom wrote:
Wed Jul 11, 2018 5:34 pm
A decent FTP server can be configured to use SSL. Proftpd for a start.
Yes and with great difficulty. With enough work vsftpd and proftpd can run FTP over SSL.
I'll have to check my configs. I'm sure it wasn't that difficult to set up.
by rpdom
Wed Jul 11, 2018 5:34 pm
Forum: Networking and servers
Topic: Make FTP server available outside of home network (Do I have everything I need?)
Replies: 11
Views: 242

Re: Make FTP server available outside of home network (Do I have everything I need?)

tpyo kingg wrote:
Wed Jul 11, 2018 5:29 pm
FTP should never be used these days, except in a few edge cases, because the user name, password, data, and the entire rest of the session are transmitted across the net completely unencrypted.
A decent FTP server can be configured to use SSL. Proftpd for a start.
by rpdom
Wed Jul 11, 2018 2:56 pm
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 835

Re: Controlling homemade solenoids using Rpi Z W

I owuldn't recommend trying to drive any solenoid directly from a gpio. They are an inductive load and could damage the gpio with reverse EMF when turned off, unless you use a diode to prevent that.

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