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by dl324
Sat Aug 10, 2019 1:46 am
Forum: General discussion
Topic: Protect over voltage on Voltage Divider ciruit
Replies: 12
Views: 354

Re: Protect over voltage on Voltage Divider ciruit

You could use a voltage comparator like LM393. Just connect the pull-up resistor to 3.3V. You can operate the comparator from 5V or your battery voltage.
by dl324
Fri Jul 26, 2019 6:52 pm
Forum: General discussion
Topic: Pc or RPi
Replies: 18
Views: 976

Re: Pc or RPi

I would like to know if it's better to buy a RPi or a computer. I think you're going to find that most members on this forum have both. I use my RPi's for writing programs to control things with RPi's. If I want to do just about anything else (browsing, office applications, circuit design/simulatio...
by dl324
Fri Jul 26, 2019 6:40 pm
Forum: Off topic discussion
Topic: Can you guys see this post?
Replies: 18
Views: 2741

Re: Can you guys see this post?

You can see the number of views (unless you're using a phone or tablet):
tmp.jpg
tmp.jpg (25.09 KiB) Viewed 2729 times
I can't recall how many posts they moderate on this forum. It took the better part of a week for my first post to be "posted".
by dl324
Sat Jul 20, 2019 7:21 pm
Forum: Troubleshooting
Topic: Strange GPIO behavior
Replies: 3
Views: 147

Re: Strange GPIO behavior

Raspian is not a real time operating system and the OS will sometimes swap out a process to do other things that are either higher priority or are at the same priority but haven't gotten their share of CPU time.

Arduino doesn't have an operating system and resources aren't shared.
by dl324
Fri Jul 12, 2019 7:47 pm
Forum: General discussion
Topic: RPi4B GPIO reading speed
Replies: 5
Views: 296

Re: RPi4B GPIO reading speed

Are you changing all of the bits in as few set/clr operations as possible?
by dl324
Wed Jul 10, 2019 3:07 pm
Forum: General discussion
Topic: GPIO extension cables, should I use them
Replies: 2
Views: 133

Re: GPIO extension cables, should I use them

How long are you talking about? If you put the amplifier close to the Pi, you shouldn't have much trouble with unshielded, non-twisted speaker hook-up wire.

If you have a problem with pick-up, use shielded cables.
by dl324
Tue Jul 09, 2019 4:35 pm
Forum: General discussion
Topic: Want to measure battery volts
Replies: 38
Views: 1766

Re: Want to measure battery volts

2- I do not know what to do with the open end cable at bottom. If you're referring to the wire dangling from the bottom of the 4.7k resistor, connect it to GND 3- I am not sure what tolerance resistors should be. I think I can find 10% ones in the market as usual. 5% and 1% should be more common th...
by dl324
Sun Jun 30, 2019 12:35 am
Forum: C/C++
Topic: Rapberry pi 4 IO memory base address
Replies: 18
Views: 1858

Re: Rapberry pi 4 IO memory base address

chipace wrote:
Sat Jun 29, 2019 8:37 pm
I used a simple C program to toggle one pin as fast as possible and I am measuring 12.5MHz (80ns period with 25% duty cycle).
I get 17MHz from Pi 0; 29MHz with compiler optimization.
by dl324
Wed Jun 26, 2019 5:55 pm
Forum: Français
Topic: Pi Zéro, potentiomètre et afficher led 8 segments
Replies: 5
Views: 479

Re: Pi Zéro, potentiomètre et afficher led 8 segments

RPi Zero doesn't have any analog inputs. You'd have to add a module to do analog to digital conversion.

RPi Zero n'a pas d'entrées analogiques. Vous devez ajouter un module pour effectuer une conversion analogique-numérique.
by dl324
Tue Jun 25, 2019 11:52 pm
Forum: C/C++
Topic: How to use c/c++ to run my rpi 0
Replies: 8
Views: 792

Re: How to use c/c++ to run my rpi 0

dharanivel wrote:
Tue Jun 25, 2019 10:27 pm
Please tell me how to use c/c++ to run my rpi0.
If you know how to program in C or C++ on Unix/Linux, you already know how to do it on RPi.
by dl324
Tue Jun 25, 2019 11:49 pm
Forum: Beginners
Topic: What projects I can make with Raspberry Pi 3
Replies: 8
Views: 442

Re: What projects I can make with Raspberry Pi 3

dreamincode wrote:
Tue Jun 25, 2019 10:30 pm
Please give me some ideas, thanks
You are limited only by your imagination. Find something that you've always thought should be "fixed" with something you can do with Pi and do it.
by dl324
Tue Jun 25, 2019 7:53 pm
Forum: General discussion
Topic: New raspberry pi big mistake (my opinion)
Replies: 14
Views: 2234

Re: New raspberry pi big mistake (my opinion)

How do you know in advance if a site or application is untrustworthy? The big hole - Javascript - is that not almost everywhere? If so, avoiding it would essentially require giving up the use of graphical internet browsers. You can start by disabling Javascript in your browser. When some site needs...
by dl324
Tue Jun 25, 2019 5:51 pm
Forum: General discussion
Topic: New raspberry pi big mistake (my opinion)
Replies: 14
Views: 2234

Re: New raspberry pi big mistake (my opinion)

I’m excited for the release of the new raspberry pi but I’m sad that the CPU it has is vulnerable to meltdown and spectre as the previous pi was not Any microprocessor that employs speculative execution to improve performance is susceptible to those attacks. If you want to avoid that, then you need...
by dl324
Sat Jun 22, 2019 7:08 pm
Forum: Beginners
Topic: How to make the GPIO connections more robust
Replies: 10
Views: 1085

Re: How to make the GPIO connections more robust

So is there a way I can make the GPIO pins more strongly secured by the pi? More secure than what? What are you currently doing? And is there any way I can prevent the pi from getting burnt or fused? Don't overload any outputs, operate inputs within specifications, don't short things. Also, I was r...
by dl324
Sat Jun 22, 2019 4:24 pm
Forum: Beginners
Topic: Installing VNC for NOOBS
Replies: 3
Views: 398

Re: Installing VNC for NOOBS

If you're going to use Raspian desktop, skip NOOBS and just copy Raspian to your microSD card. Raspian desktop with recommended additions includes RealVNC.
by dl324
Sat Jun 15, 2019 3:17 am
Forum: Troubleshooting
Topic: Using GPIO
Replies: 9
Views: 500

Re: Using GPIO

You're using different GPIO's. The first script is using Broadcom numbers and the second uses Pi numbering. Comment out the setmode command in the first script and they'll use the same GPIO.

You shouldn't be making resistance measurements with a DVM on a powered circuit.
by dl324
Fri Jun 14, 2019 3:49 pm
Forum: Beginners
Topic: Reboot raspberry pi and run a script after
Replies: 5
Views: 252

Re: Reboot raspberry pi and run a script after

Nathan1258 wrote:
Fri Jun 14, 2019 3:33 pm
Basically how do I continue running the script once the pi has rebooted again?
Can't be done. You can start the script automatically at reboot, but you can't have it resume. The current state can't be maintained across boots.
by dl324
Fri Jun 14, 2019 1:17 am
Forum: Troubleshooting
Topic: Failed boot after update/upgrade
Replies: 1
Views: 111

Re: Failed boot after update/upgrade

If it were me, I'd copy Raspian to a new SD card. Boot to it and mount your original SD card with a USB adapter and copy the important files to the new card. Then, before doing anything significant in the future, back up the image. Also make backups of your work whenever you do something you don't w...
by dl324
Thu Jun 13, 2019 6:19 pm
Forum: Beginners
Topic: HOOBS, NOOBS: Differences?
Replies: 4
Views: 291

Re: HOOBS, NOOBS & BOOBS: Differences?

So, it wouldn't be wrong for me to make an image backup of that uSD card for safety, and then to reformat it and using Etcher to put Raspbian on it? I would guess that this would give me pretty much the same thing as on my first RPi, which I got less than 2 weeks ago. If you like how you have your ...
by dl324
Thu Jun 13, 2019 2:53 pm
Forum: General discussion
Topic: CMOS Technology on BCM2837
Replies: 4
Views: 368

Re: CMOS Technology on BCM2837

Especially it's would be great to know what is the size of CMOS transistor (in nm). It's unlikely that they only used one transistor size. The smallest transistors will be in the memory array and they're typically smaller than any logic transistors because the array is very regular and they can opt...
by dl324
Thu Jun 13, 2019 3:37 am
Forum: Troubleshooting
Topic: Defective Pi Zero? No power
Replies: 3
Views: 191

Re: Defective Pi Zero? No power

Pi Zero W only has a green LED that indicates activity on the SD card.

Have you measured the 5V and 3.3V pins on the header, or holes if you didn't buy the version with headers installed?
by dl324
Thu Jun 13, 2019 2:10 am
Forum: General discussion
Topic: Create a desktop shortcut
Replies: 3
Views: 280

Re: Create a desktop shortcut

Is the file executable?

I just tried and you're going to be prompted whether you want to execute the file. That seems to be a feature.
by dl324
Wed Jun 12, 2019 1:29 pm
Forum: General discussion
Topic: Forgot my password.
Replies: 11
Views: 667

Re: Forgot my password.

Moomoo5 wrote:
Tue Jun 11, 2019 8:25 pm
I have so many files though.
I'd suggest you get in the habit of backing up work you want to save. I do it daily. I copy the tar files to my Windows PC that's also backed up daily.
by dl324
Sun Jun 09, 2019 9:20 pm
Forum: Troubleshooting
Topic: RasPi B+ Stopped working suddenly, won't boot back up
Replies: 8
Views: 345

Re: RasPi B+ Stopped working suddenly, won't boot back up

Jake.B wrote:
Sun Jun 09, 2019 4:53 am
The light still comes on so I guess something is going right?
If you're referring to the red LED, that's a 5V present indicator. There isn't an LED on 3.3V, you need to measure on the header.
by dl324
Sun Jun 09, 2019 2:26 pm
Forum: General discussion
Topic: How do I keep my Pi clean?
Replies: 16
Views: 866

Re: How do I keep my Pi clean?

DarkPlatinum wrote:
Sun Jun 09, 2019 10:21 am
How do I decrease the amount of dust going into the Pi? Is there some sort of air filter I can put on top of the fan?
Why bother with a filter? You probably have a lot of things gathering dust. Just dust them off if it builds up enough to bother you.

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