Go to advanced search

by rpdom
Thu Jul 19, 2018 5:17 pm
Forum: General discussion
Topic: Relay Module KY-019 5V
Replies: 189
Views: 8442

Re: Relay Module KY-019 5V

I closely watched his perhaps 50 years old ugly calculator and forgot what he was saying. There were no calculators like that 50 years ago. There were some purely mechanical ones. Some worked by pulling a lever to do the calculation. Others used electricity to drive a motor to do the work. His othe...
by rpdom
Thu Jul 19, 2018 5:00 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3B+ overheating during zero activity or low activity (PiAware & Dump1090-fa Installed)
Replies: 15
Views: 260

Re: Raspberry Pi 3B+ overheating during zero activity or low activity (PiAware & Dump1090-fa Installed)

Room temperature 25.250°C
Raspi 3B+ temperature 60.686°C

Official case with lid on.

Nothing major running on it yet.
by rpdom
Thu Jul 19, 2018 4:53 pm
Forum: General discussion
Topic: RPi (Zero) in extreme temperatures experiences
Replies: 7
Views: 176

Re: RPi (Zero) in extreme temperatures experiences

W. H. Heydt wrote:
Thu Jul 19, 2018 4:48 pm
That's the Pi3B. The defaults have been: Model B, 700MHz. Model A, 700MHz, Model B+, 700MHz, Model A+, 700MHz, Pi2B (both variants), 900MHz, Pi0/Pi0W, 1GHz, Pi3B, 1.2GHz, Pi3B+, 1.4GHz.
IIRC, when I got my first Pi 1B (May 2012), the default was 600MHz, later raised to 700.
by rpdom
Thu Jul 19, 2018 7:05 am
Forum: General programming discussion
Topic: What Does Hiding the Details of I/O in Library Calls Teach?
Replies: 55
Views: 1031

Re: What Does Hiding the Details of I/O in Library Calls Teach?

bensimmo wrote:
Thu Jul 19, 2018 6:32 am
That's when you get Orangutans.
In the library?
by rpdom
Thu Jul 19, 2018 7:04 am
Forum: General discussion
Topic: How can i use my own domain on Raspberry Pi to serve a website?
Replies: 4
Views: 116

Re: How can i use my own domain on Raspberry Pi to serve a website?

Unless you host your own nameservers, you leave those fields alone. The provider should have another page for adding an IP address A or AAAA record to your domain name.
by rpdom
Wed Jul 18, 2018 6:43 pm
Forum: General discussion
Topic: Relay Module KY-019 5V
Replies: 189
Views: 8442

Re: Relay Module KY-019 5V

I have recently bought some 220VAC 15W LED lamps. They use transformers (I guess from 220VAC to 12/24DAC) and say they are flicker free. Unlikely, almost always capacitive-dropper circuits nowadays. BigClive on Youtube does some interesting tear-downs of this sort of thing and reverse engineers the...
by rpdom
Tue Jul 17, 2018 8:22 pm
Forum: Python
Topic: Light off function problem
Replies: 1
Views: 69

Re: Light off function problem

Looks like a simple typo in the code

Code: Select all

        var lightOff = function() {
            document.getElementById('myImage').src='/static/pic_bulboff.gif';
            sendCommand('On');
            console.log("Light Off");
        };
Shouldn't that be sendCommand('Off'); ?
by rpdom
Tue Jul 17, 2018 6:21 pm
Forum: General discussion
Topic: How to automatically run a program in Raspberry Pi?
Replies: 15
Views: 340

Re: How to automatically run a program in Raspberry Pi?

Actually, my server.c is C++ program but I can use "g++ server.c -o server -lwiringPi" to compile it. After that, I got a server exe file. That would be a "server" executable file. Not an "exe" which is a windows thing. So, your file should be called server and the line to run it should be ExecStar...
by rpdom
Tue Jul 17, 2018 5:23 am
Forum: General discussion
Topic: Using Hard Drive with Raspberry Pi
Replies: 45
Views: 9282

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: 296

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: 31920

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: 107

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: 143

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: 259

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: 242

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: 259

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: 303

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: 645

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: 147

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: 91

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: 237

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: 176

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: 236

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: 288

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: 147

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).

Go to advanced search