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by mahjongg
Mon Feb 19, 2018 6:35 pm
Forum: General discussion
Topic: Is my Pi Zero W faulty?
Replies: 4
Views: 124

Re: Is my Pi Zero W faulty?

Yes, you must make it so that pressing the button presents a different voltage (high or low) to the GPIO than when not pressing the button, you can do this in two ways; use a pulldown resistor to pull the resistor to a logical low voltage (lower than 0.8 Volt), and then use a button to put a high (h...
by mahjongg
Mon Feb 19, 2018 3:56 pm
Forum: Beginners
Topic: how do I uninstall programs?
Replies: 15
Views: 254

Re: how do I uninstall programs?

First, you should know that as Linux is very much case sensitive JMRI and jmri are two different things. also apt-get alone doesn't do anything, as it expect to be told what to do, and JMRI isn't something it can do. type "man apt-get", and read the result (man is the built in manual system of linux...
by mahjongg
Mon Feb 19, 2018 3:54 pm
Forum: Python
Topic: Infinite loop malfunction
Replies: 15
Views: 224

Re: Infinite loop malfunction

Due to contact bounce a pushbutton might not produce one event when pressed/released, it is easily possible it produced a very rapid stream of 15 "open/close events", that is normal, and must be resolved with either hardware, or software to remove the contact bounce.
by mahjongg
Mon Feb 19, 2018 3:42 pm
Forum: General discussion
Topic: Is my Pi Zero W faulty?
Replies: 4
Views: 124

Re: Is my Pi Zero W faulty?

No, it is not broke, and this is normal! why do you expect a wire that isn't connected to anything to carry "zero voltage"? in the unavoidable neighborhood of magnetic fields in your house this wont be true, as any wire acts like an antenna, and picks up electromagnetic radiation. Without an interna...
by mahjongg
Mon Feb 19, 2018 12:37 pm
Forum: General discussion
Topic: Replacing the Pi3 ethernet port?
Replies: 19
Views: 1202

Re: Replacing the Pi3 ethernet port?

The LAN9514 documentation https://www.google.nl/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwjV79GK_rHZAhXLfFAKHd7nAqEQFggzMAE&url=http%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2F00002306A.pdf&usg=AOvVaw1SZhhaIJKJ32-7ZoJWQ-N1 should provide you with more details about the magnet...
by mahjongg
Mon Feb 19, 2018 10:09 am
Forum: Troubleshooting
Topic: I fried my Raspberry Pi 3 B
Replies: 8
Views: 213

Re: I fried my Raspberry Pi 3 B

Yes, the setup of this circuit is such that the polyfuse should protect the over-voltage diode, but when it burns out it will most often simply short the power supply, unless the power supply is something like a car battery, the short-circuit D5 provides is enough to protect the rest of the PI. I wo...
by mahjongg
Mon Feb 19, 2018 10:02 am
Forum: Automation, sensing and robotics
Topic: Doorbell detection
Replies: 6
Views: 148

Re: Doorbell detection

@pcmanbob, yes that is exactly it, with the extra bonus of the 1K resistor, which adds extra security against programming errors.
Thanks for your help.
by mahjongg
Sun Feb 18, 2018 10:17 pm
Forum: Raspberry Pi Desktop for PC and Mac
Topic: cannot pair bluetooth mouse (debian x86)
Replies: 11
Views: 370

Re: cannot pair bluetooth mouse (debian x86)

All postings about x86 Debian will be moved here, no matter where they are found. simply to avoid confusion between Raspbian and x86 Debian. debian running on a PC with the raspberry PI desktop is NOT the same thing as Raspbian. And if the title is confusing, I will not hesitate to remove the confus...
by mahjongg
Sun Feb 18, 2018 10:09 pm
Forum: Automation, sensing and robotics
Topic: Doorbell detection
Replies: 6
Views: 148

Re: Doorbell detection

OOPS! no that circuit is even worse than your original. connect pin 4 (of the PC817) directly to GND connect pin 3 to GPIO 18 place the R2 4K7 resistor with one end connected to 3V3, and the other end to pin 3 (and thus also to GPIO 18) add a new 1N4148 diode, and connect it cathode to pin 1 (of the...
by mahjongg
Sun Feb 18, 2018 10:01 pm
Forum: Networking and servers
Topic: GPS module with serial interface to Raspberry Pi with an USB-Serial Port
Replies: 5
Views: 93

Re: GPS module with serial interface to Raspberry Pi with an USB-Serial Port

yes, that USB-serial adapter has a DB9 connector, and obviously uses RS232 levels, so it should work fine with an RS232 compatible GPS module.

note that some USB-serial adapter use a fake Chinese serial interface IC, that may nor work with all Linux built in drivers, but you can safely try it.
by mahjongg
Sun Feb 18, 2018 9:42 pm
Forum: Troubleshooting
Topic: I fried my Raspberry Pi 3 B
Replies: 8
Views: 213

Re: I fried my Raspberry Pi 3 B

if its any PI BUT a PI zero, it has an overprotection device that will attempts to protect the PI by shorting the 5V supply when you put more than 6V on it. This will normally burn out the PI's polyfuse, and if you are lucky the device survives this and the fuse will self-repair if you leave it alon...
by mahjongg
Sun Feb 18, 2018 2:18 pm
Forum: Raspbian
Topic: Raspbian::Stretch
Replies: 2
Views: 92

Re: Raspbian::Stretch

split off from older topic.
by mahjongg
Sun Feb 18, 2018 2:09 pm
Forum: Nederlands
Topic: een image schrijven op SD card voor raspberrypi 3b
Replies: 1
Views: 37

Re: een image schrijven op SD card voor raspberrypi 3b

7zip is een data compressie utility, en schrijft geen images weg, en win32diskimager is sterk verouderd. gebruik een moderne image writer zoals Etcher die pakt een gecomprimeerde .img file ook zelfstandig uit, geen 7zip nodig. een image zit ook niet in NOOBS, maar download je zelfstandig, (je bent h...
by mahjongg
Sun Feb 18, 2018 2:03 pm
Forum: Networking and servers
Topic: GPS module with serial interface to Raspberry Pi with an USB-Serial Port
Replies: 5
Views: 93

Re: Raspberry Pi to a Serial Port

does the USB-serial adapter you are using use RS232 levels, and/or does the GPS module use RS232 levels (that is + and - 10Volt levels), (It should as its using ad DB09 port) if not you should use serial levels that match, as RS232 levels and "TTL" levels do not mix and match. connecting RS232 level...
by mahjongg
Sun Feb 18, 2018 1:43 pm
Forum: General discussion
Topic: My Raspberry won’t boot
Replies: 1
Views: 54

Re: My Raspberry won’t boot

read the boot problem sticky: viewtopic.php?f=28&t=58151
Is my Raspberry 3 is dead ?
unlikely unless you have blown it up, and it gets very hot.
by mahjongg
Sun Feb 18, 2018 1:41 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SMT GPIO Soldering Pointers?
Replies: 1
Views: 55

Re: SMT GPIO Soldering Pointers?

If I were you I would try to carefully bend all the SMT pins 90 degrees so that the resulting connector has (short) pins that can be sticked into the holes of the PI. other solutions are prone to being less reliable. Make sure the pin doesn't break off, and don't attempt this if the pins are made of...
by mahjongg
Sun Feb 18, 2018 12:46 pm
Forum: Automation, sensing and robotics
Topic: Doorbell detection
Replies: 6
Views: 148

Re: Doorbell detection

well, first congratulations, this could work, at least if dc is only available on the doorbell when it rings, but perhaps that is obvious. I would not send 20mA through the LED as 20mA is the maximum it can handle, so I would go for something a bit less, so lets raise the resistor to say 520 Ohm (a ...
by mahjongg
Sat Feb 17, 2018 2:05 pm
Forum: Troubleshooting
Topic: Password reset on its own
Replies: 4
Views: 122

Re: Password reset on its own

when you have problems entering your password, it might be because your keyboard settings are not what you expect, so try to enter your password in the user name field, so you can see what you are actually typing in.
by mahjongg
Sat Feb 17, 2018 2:01 pm
Forum: Troubleshooting
Topic: Unable to Login Anymore
Replies: 56
Views: 93340

Re: Unable to Login Anymore

when you have problems entering your password, it might be because your keyboard settings are not what you expect, so try to enter your password in the user name field, so you can see what you are actually typing in.
by mahjongg
Sat Feb 17, 2018 1:44 pm
Forum: Advanced users
Topic: Linux Kernel Booting
Replies: 1
Views: 130

Re: Linux Kernel Booting

not really a beginners issue, moved to advanced users.
by mahjongg
Sat Feb 17, 2018 1:39 pm
Forum: Beginners
Topic: Confused about voltages
Replies: 5
Views: 188

Re: Confused about voltages

if Vdd is NOT 5Volt, but lower (say 4.5V) then ViH would also become lower (4.5 x 0.7 = 3.15V) so that would solve it. That is, IF Vdd can be lowered with impunity (with the device still working from it). If not, some level converter must be used to lift the high output voltage above the ViH limit.
by mahjongg
Sat Feb 17, 2018 1:20 pm
Forum: General discussion
Topic: Raspbian has a little problem.
Replies: 8
Views: 428

Re: Raspbian has a little problem.

5 votes for no, no votes for yes, deleted the poll after multiple complaints about it.
Also, please don't "bump", its agains good behaviour here.
by mahjongg
Sat Feb 17, 2018 1:13 pm
Forum: Troubleshooting
Topic: Two Pi zero's, both on network with same IP address!
Replies: 8
Views: 64

Re: Two Pi zero's, both on network with same IP address!

split of from six year old post, from several OS versions back, that was written when no PI had built in wifi and PI zero's did not exist, so previous info is now useless.

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