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by DougieLawson
Tue Dec 18, 2018 8:00 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Enable 3 Wire SPI aka Bidirectional, half duplex SPI
Replies: 7
Views: 101

Re: Enable 3 Wire SPI aka Bidirectional, half duplex SPI

It a bastardised version of SPI where the master doesn't send data to the slave for an input device. For something like a neopixel you only connect MOSI as the device never sends any data on MISO.
by DougieLawson
Tue Dec 18, 2018 7:57 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: LCD /TFT display with SPI
Replies: 9
Views: 170

Re: LCD /TFT display with SPI

C/D can stand for SCL and SDA or SPI Clk and SPI MOSI(data). Eh? C/D stands for C ommand or D ata. As I posted elsewhere -SPI is non standard standard but C/D CAN STAND ONLY for C/D nothing else ! With display devices it is always command or data. Effectively it's a ninth bit added on an eight bit ...
by DougieLawson
Mon Dec 17, 2018 5:08 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: LCD /TFT display with SPI
Replies: 9
Views: 170

Re: LCD /TFT display with SPI

Gavinmc42 wrote:
Mon Dec 17, 2018 5:00 am
C/D can stand for SCL and SDA or SPI Clk and SPI MOSI(data).
Eh? C/D stands for Command or Data.
by DougieLawson
Mon Dec 17, 2018 4:58 pm
Forum: Beginners
Topic: How can the raspberry be shutdown with a python script and no sudo?
Replies: 12
Views: 799

Re: How can the raspberry be shutdown with a python script and no sudo?

Reboot is a parameter for the systemctl program

Code: Select all

pi raspberrypi =NOPASSWD: /sbin/reboot
should work, but I can't be bothered to test it.
by DougieLawson
Mon Dec 17, 2018 4:54 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Enable 3 Wire SPI aka Bidirectional, half duplex SPI
Replies: 7
Views: 101

Re: Enable 3 Wire SPI aka Bidirectional, half duplex SPI

Three wire SPI means you only connect MISO (master in, slave out). MOSI is left as no connection (NC).
by DougieLawson
Mon Dec 17, 2018 4:44 pm
Forum: Beginners
Topic: How can the raspberry be shutdown with a python script and no sudo?
Replies: 12
Views: 799

Re: How can the raspberry be shutdown with a python script and no sudo?

/sbin/reboot needs an entirely seperate line in your sudoers file.
by DougieLawson
Mon Dec 17, 2018 4:39 pm
Forum: Weather station
Topic: Error uploading again
Replies: 3
Views: 46

Re: Error uploading again

Try sudo killall interrupt_daemon.py then attempt to restart it. If that doesn't work try a reboot.
by DougieLawson
Sun Dec 16, 2018 9:18 pm
Forum: Troubleshooting
Topic: mysql server is not accessibel until i mak e a vnc connection
Replies: 2
Views: 56

Re: mysql server is not accessibel until i mak e a vnc connection

Open up /etc/mysql/my.cnf

Find the bind-address line and change it to

Code: Select all

bind-address 0.0.0.0
by DougieLawson
Sun Dec 16, 2018 6:53 pm
Forum: Official Foundation Display
Topic: 7" touchscreen not registering input
Replies: 3
Views: 91

Re: 7" touchscreen not registering input

If it's a Raspberry Pi B+, A+, 2B, 3B, 3B+, 3A+ then pull off the green and yellow wires if you've got them wired to the GPIO I2C pins.
by DougieLawson
Sun Nov 18, 2018 11:54 am
Forum: Python
Topic: Can't find module in 3.5 but can in 2.7
Replies: 4
Views: 351

Re: Can't find module in 3.5 but can in 2.7

Use sudo pip3 install ... to install for python3. Use sudo pip install ... for python2 stuff.
by DougieLawson
Sun Nov 18, 2018 11:52 am
Forum: General discussion
Topic: mysql removal
Replies: 1
Views: 99

Re: mysql removal

sudo apt purge mysql* mariadb*
by DougieLawson
Sun Nov 18, 2018 10:46 am
Forum: Other programming languages
Topic: javascript not working on RPi 3
Replies: 32
Views: 2060

Re: javascript not working on RPi 3

That's no excuse for sloppy security. It may not be connected today, it may be in the future.

What's so hard about doing it the right way now. You'll learn something in the process.
by DougieLawson
Sun Nov 18, 2018 10:43 am
Forum: Troubleshooting
Topic: command sudo apt-get update stuck at 0%
Replies: 12
Views: 455

Re: command sudo apt-get update stuck at 0%

Your Raspberry is not connected to the public internet in that case.

You can see that with the 169.254.xxx.xxx address. Check the cable from your RPi to your router.
by DougieLawson
Sun Nov 18, 2018 10:39 am
Forum: Troubleshooting
Topic: no /home/pi/.config/lxsession ?
Replies: 8
Views: 551

Re: no /home/pi/.config/lxsession ?

Simon Long needs a session with my well polished educational baseball bat. He has done this stuff too often and it's 100% unacceptable. A software upgrade shouldn't break things unless it's a switch from Stretch to Buster when you'll be on the lookout for breakages. If I did this for a commercial cl...
by DougieLawson
Sun Nov 18, 2018 10:34 am
Forum: AIY Projects
Topic: None of the assistant_library voice demos work
Replies: 16
Views: 1828

Re: None of the assistant_library voice demos work

If you do choose the update or have already done it you'll need to clone the repo at https://github.com/google/aiyprojects-raspbian to get your AIY running again.

That was updated a couple of days ago.
by DougieLawson
Sun Nov 18, 2018 10:29 am
Forum: Troubleshooting
Topic: no /home/pi/.config/lxsession ?
Replies: 8
Views: 551

Re: no /home/pi/.config/lxsession ?

Use ls -la as .config is a hidden folder.
by DougieLawson
Sun Nov 18, 2018 10:27 am
Forum: C/C++
Topic: Can not install C library on raspberry pi3
Replies: 6
Views: 550

Re: Can not install C library on raspberry pi3

Go and ask the hardware/software vendor to provide a library for your alien hardware.

Move your application back to an X86 / X86_64 computer like an Intel Nuc.
by DougieLawson
Sun Nov 18, 2018 10:24 am
Forum: Troubleshooting
Topic: no /home/pi/.config/lxsession ?
Replies: 8
Views: 551

Re: no /home/pi/.config/lxsession ?

The stupid desktop update moved that to ~/oldconfig/.config/...

Move it back and it will start working.

I've no idea why the update didn't ask what I wanted or give an option to keep the file in place. It's a pile of stinking stuff to just arbitrarily break things in this way.
by DougieLawson
Sat Nov 17, 2018 8:08 pm
Forum: Raspbian
Topic: Pre login message screen
Replies: 2
Views: 613

Re: Pre login message screen

/etc/issue works for locally connected try devices.

For remote connections it's /etc/issue.net
by DougieLawson
Sat Nov 17, 2018 6:43 pm
Forum: Beginners
Topic: Pi VPN - Tomato Shibby Router
Replies: 3
Views: 246

Re: Pi VPN - Tomato Shibby Router

An OpenVPN xxx.ovpn file needs all three sections <ca>...</ca><cert>...</cert><key>...</key>.

CA is the certificate authority certificate (usually self-signed). CERT is your client certificate (signed with the CA cert). KEY is the private key (so needs to be kept secure) for your CERT.
by DougieLawson
Sat Nov 17, 2018 6:37 pm
Forum: Python
Topic: error in the code
Replies: 3
Views: 358

Re: error in the code

The other thing is that GPIO4 is usually used for the kernel 1-wire driver. If you're trying to read a temp value from a 1-wire device then the kernel driver is your friend (don't need any of that python code you've half posted). Enable 1-wire in the GUI. Then read your 1-wire sensor with this pytho...
by DougieLawson
Sat Nov 17, 2018 6:30 pm
Forum: Advanced users
Topic: PI 2 B CAN CHOOSE WI FI from 2 NETWORKS?
Replies: 3
Views: 441

Re: PI 2 B CAN CHOOSE WI FI from 2 NETWORKS?

country=GB ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 network={ ssid="NETWORK2" priority=90 psk="passwordfornet2" } network={ ssid="NETWORK1" priority=100 psk="passwordformostlikelytobeusednetwork" } network={ ssid="NETWORK3" priority=80 psk="passwordforleastpreferednet...
by DougieLawson
Sat Nov 17, 2018 6:14 pm
Forum: Weather station
Topic: Total noob here. Personal WS
Replies: 21
Views: 1065

Re: Total noob here. Personal WS

On my system that stuff is in /etc/apache2/mods-available/php7.0.conf

so sudo a2enmod php7.0 should activate it. I've added that to my pull request for the new version of the weather-station-www code.
by DougieLawson
Sat Nov 17, 2018 5:48 pm
Forum: Weather station
Topic: Total noob here. Personal WS
Replies: 21
Views: 1065

Re: Total noob here. Personal WS

Then I can't see how your web site is failing, that log looks normal.
by DougieLawson
Sat Nov 17, 2018 5:11 pm
Forum: Troubleshooting
Topic: RPIZW - Wifi Chip.
Replies: 29
Views: 775

Re: RPIZW - Wifi Chip.

ShiftyRP wrote:
Sat Nov 17, 2018 3:43 pm
So how did NOOBS be able to detect my network then?
No idea, because my crystal ball went offline in the "Great Crystal Ball Disaster of 1989" and you're not telling us everything that you've tried and failed to do to resolve things.

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