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by mahjongg
Fri Dec 13, 2019 6:36 pm
Forum: General discussion
Topic: Hdmi input
Replies: 1
Views: 83

Re: Hdmi input

NO!

both are outputs.
by mahjongg
Thu Dec 12, 2019 5:50 pm
Forum: Troubleshooting
Topic: Black screen after boot up
Replies: 12
Views: 2589

Re: Black screen after boot up

can u please reply me as soon as possible to this number 9133111485.please i am doing project on raspberry pi.can u please rply me quickly. No we can't, we don't know what the number means, if its a telephone number we don't know which country you live in (although, you share your name with a Bolly...
by mahjongg
Tue Dec 10, 2019 10:49 pm
Forum: Off topic discussion
Topic: My new ZX81 clone, built from discrete pin-through hole components
Replies: 17
Views: 3643

Re: My new ZX81 clone, built from discrete pin-through hole components

Updated above picture, now it has contact fingers.
by mahjongg
Mon Dec 09, 2019 6:10 pm
Forum: Beginners
Topic: VNC - Pi's do not appear in team
Replies: 12
Views: 1541

Re: VNC - Pi's do not appear in team

Your answer is long obsolete, as the OS has changed considerably in a few year.

That is why re-opening a long dead post (necro) is frowned upon, and only causes irritation and frustration.

So locking.
by mahjongg
Mon Dec 09, 2019 12:29 pm
Forum: General discussion
Topic: HDMI audio doesn't work
Replies: 3
Views: 138

Re: HDMI audio doesn't work

If you have an RPI4, then note there is only audio coming from the left HDMI0 port, not from the right HDMI1 port.
by mahjongg
Mon Dec 09, 2019 12:01 am
Forum: General discussion
Topic: Trying to connect CQ Robot Speakers to a Raspberry Pi 3 Model B+
Replies: 1
Views: 46

Re: Trying to connect CQ Robot Speakers to a Raspberry Pi 3 Model B+

You need a (stereo) speaker driver between the AV output of the RPI, and the speakers.

and switch HDMI audio to the AV output
by mahjongg
Sun Dec 08, 2019 11:50 pm
Forum: Automation, sensing and robotics
Topic: Dimming a 0-10v dimmable light Problem
Replies: 3
Views: 210

Re: Dimming a 0-10v dimmable light Problem

The LM324 is quite an old and simple chip, close to 0V the output of this opamp can only sink a few dozen uA (micro Amp), not enough to overcome the current the dimmer input is injecting into the opamp. Solution: Add a -12V negative voltage to the V- supply. See the data sheet figure 11 at page 9. O...
by mahjongg
Sun Dec 08, 2019 2:25 pm
Forum: Beginners
Topic: Wifi connectivity issue in Raspberry pi 4
Replies: 4
Views: 149

Re: Wifi connectivity issue in Raspberry pi 4

Do you use a 4K monitor (1920x1080)? Normal 4K monitor settings may cause a disturbance between emitted frequencies of this HDMI mode, and frequencies used by channel 1 of 2.4GHz WiFi. A special tweaked 4K mode has been introduced recently to fix the interference. see https://www.raspberrypi.org/for...
by mahjongg
Sun Dec 08, 2019 2:21 pm
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 951
Views: 114179

Re: Raspberry Pi 4 Thread - general discussion

Yes, can we please go back on topic?!
by mahjongg
Sun Dec 08, 2019 2:05 pm
Forum: Troubleshooting
Topic: Using a PQ-12-R Linear Actuator with Pi 3 B+
Replies: 3
Views: 367

Re: Using a PQ-12-R Linear Actuator with Pi 3 B+

Its used as a (linear) servo motor, so controlled with a PWM signal (with a maximum duty cycle of 20%), and an external 6V power supply.

because the PWM signal must have a 5V amplitude a level converter between the 3V3 PWM output, and the 5V servo input is necessary.
by mahjongg
Sun Dec 08, 2019 1:51 pm
Forum: Beginners
Topic: Will I burn my RPI if I accidentially provide a large voltage to any 3.3v GPIO pin?
Replies: 15
Views: 440

Re: Will I burn my RPI if I accidentially provide a large voltage to any 3.3v GPIO pin?

In short: RPI GPIO inputs are NOT 5V tolerant! Longer version: They are not even more than 3.9 to 4.0V tolerant, in fact any voltage greater than 0.6 to 0.7V (a diode forward drop) more than the GPIO supply voltage (3.3Volt) , that is 3.3+0.7=4.0V, can cause a " latchup ", and the current that cause...
by mahjongg
Sun Dec 08, 2019 1:26 pm
Forum: Deutsch
Topic: Zero W bootet nicht.
Replies: 5
Views: 138

Re: Zero W bootet nicht.

https://translate.google.nl/translate?hl=nl&sl=en&tl=de&u=https%3A%2F%2Fwww.raspberrypi.org%2Fforums%2Fviewtopic.php%3Ff%3D28%26t%3D58151 Es scheint, dass der Zero keine Power-LED hat, sondern nur eine Aktivitäts-LED, die nur dann aufleuchtet, wenn sie tatsächlich von der SD-Karte gelesen werden kan...
by mahjongg
Fri Dec 06, 2019 1:47 pm
Forum: Beginners
Topic: Connecting 5V pullup to Pi GPIO
Replies: 33
Views: 919

Re: Connecting 5V pullup to Pi GPIO

Thinking about it, any resistor between the GPIO pin and 0V ought to make it 3V3 safe, whether 5V coming in from the Arduino power rail or the Arduino I/O pin if set as an output high ... Not true, if you claim that a largish pullup to 5V is safe, you only need a microscopic current flow from a >4V...
by mahjongg
Fri Dec 06, 2019 1:41 pm
Forum: General discussion
Topic: Portable Web Proxy Run on a Raspberry Pi Zero W??
Replies: 3
Views: 119

Re: Portable Web Proxy Run on a Raspberry Pi Zero W??

Seems to be of questionable legality, so locking.
by mahjongg
Thu Dec 05, 2019 6:47 pm
Forum: Off topic discussion
Topic: Does this forum have a 'dark' mode ?
Replies: 23
Views: 1028

Re: Does this forum have a 'dark' mode ?

We are just explaining that doing that to this forum isn't simple.
or TLDNR
don't expect it to happen....
by mahjongg
Thu Dec 05, 2019 1:52 pm
Forum: Nederlands
Topic: Hardware aansluiten op GPIO pins.
Replies: 12
Views: 3666

Re: Hardware aansluiten op GPIO pins.

Ja als je de RXB6 met 3,3V voedt dan komt er natuurlijk ook maar 3.3V uit zijn uitgang.

hou trouwens de ontvanger wat verder weg van de RPI, anders stoort de RPI waarschijnlijk de de ontvanger!
by mahjongg
Thu Dec 05, 2019 1:27 pm
Forum: Off topic discussion
Topic: Does this forum have a 'dark' mode ?
Replies: 23
Views: 1028

Re: Does this forum have a 'dark' mode ?

rpdom wrote:
Thu Dec 05, 2019 10:38 am
mahjongg wrote:
Thu Dec 05, 2019 9:58 am
I don't like it, too gloomy!
Yeah, Dougie's userpic does that to me too :lol:
Dougie's userpic was the only part that was inverted twice, inverted once it was too horrible. LOL.
by mahjongg
Thu Dec 05, 2019 9:58 am
Forum: Off topic discussion
Topic: Does this forum have a 'dark' mode ?
Replies: 23
Views: 1028

Re: Does this forum have a 'dark' mode ?

This is how it would look if the forum inverted the colors (except the pictures in it obviously).
inverted forum.png
inverted forum.png (73.92 KiB) Viewed 718 times
I don't like it, too gloomy!
by mahjongg
Wed Dec 04, 2019 11:04 pm
Forum: Français
Topic: lancer un programme avec un interrupteur
Replies: 17
Views: 379

Re: lancer un programme avec un interrupteur

Ne comptez pas sur les tractions internes (programmables), elles sont beaucoup trop faibles, (>50K) utilisez plutôt une traction externe forte (entre 1K5 et 4K7) et tirez jusqu'à 3V3, mais PAS 5V.
by mahjongg
Wed Dec 04, 2019 10:56 pm
Forum: Off topic discussion
Topic: Does this forum have a 'dark' mode ?
Replies: 23
Views: 1028

Re: Does this forum have a 'dark' mode ?

it would be nice to be able to adjust the forum to use white on black If you are using windows you might try this (to see how it looks). Use the snipping tool to make a snip off the whole screen, (make sure its has some coloured parts too) copy to clipboard. Open Paint, and paste the snip. Select e...
by mahjongg
Wed Dec 04, 2019 2:06 am
Forum: General discussion
Topic: Raspberry Pi 4 is not a replacement for a real PC, (as it doesn't have Skype) sorry!
Replies: 72
Views: 2717

Re: Raspberry Pi 4 is not a replacement for a real PC, (as it doesn't have Skype) sorry!

Removed the most trolling and nonsensical rant a poster (diogen151) made in this thread, it went into >/dev/null ;-) . Skype does not a PC make... and only a Microsoft lackey who drank the Microsoft kool aid would claim so, just to mask that there are other video messaging systems out there that can...
by mahjongg
Tue Dec 03, 2019 7:47 pm
Forum: Troubleshooting
Topic: Pi Zero W gpio pins fluctuating
Replies: 24
Views: 528

Re: Pi Zero W gpio pins fluctuating

IMHO the internal software controlled pull-ups (pull-downs) are far too weak (about 50 Kilo Ohm) for any use other than to pull-up (down) a completely unconnected GPIO. The moment you attach a few centimeters of wire to such a GPIO in an electromagnetic "noisy" environment, the wire can act like an ...

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