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by salvato
Wed Aug 05, 2020 6:10 am
Forum: General discussion
Topic: A bunch of solar usb battery packs
Replies: 22
Views: 658

Re: A bunch of solar usb battery packs

5v time average current times the time interval. If you want to be (engineering) conservative, use the nominal max current spec of 3A. Doing that, you are drawing 15W or 15Wh/hr. 15Wh/hr * 24 hr = 360Wh. 360W to be pedantic... Nope. Do the dimensional analysis. Sorry. You are right!
by salvato
Wed Aug 05, 2020 5:47 am
Forum: General discussion
Topic: A bunch of solar usb battery packs
Replies: 22
Views: 658

Re: A bunch of solar usb battery packs

W. H. Heydt wrote:
Wed Aug 05, 2020 5:07 am
xevilstar1 wrote:
Wed Aug 05, 2020 4:13 am
How can I know how much energy my pi rig draws in 24 hours ?
5v time average current times the time interval. If you want to be (engineering) conservative, use the nominal max current spec of 3A. Doing that, you are drawing 15W or 15Wh/hr. 15Wh/hr * 24 hr = 360Wh.
360W to be pedantic...
by salvato
Thu Jul 30, 2020 6:48 am
Forum: Other projects
Topic: Downloading Images from Weather Satellites with cURL & Wget
Replies: 2
Views: 314

Re: Downloading Images from Weather Satellites with cURL & Wget

Really interesting.
It would be much more interesting for me if there were also accessible satellites giving images of the Europe.
by salvato
Fri Jul 24, 2020 7:25 am
Forum: Automation, sensing and robotics
Topic: Erratic stepper motor movement with DRV8825 (Floating RPi ground?)
Replies: 8
Views: 503

Re: Erratic stepper motor movement with DRV8825 (Floating RPi ground?)

From the drv8825 data sheet, the maximum VIL is 0.7V. Maybe some electrical noise can reach a value greater than 0.7V on the line. Have you enabled Pull-up or Pull-down on the RPi GPIO output ?
by salvato
Thu Jul 23, 2020 2:57 pm
Forum: Automation, sensing and robotics
Topic: Erratic stepper motor movement with DRV8825 (Floating RPi ground?)
Replies: 8
Views: 503

Re: Erratic stepper motor movement with DRV8825 (Floating RPi ground?)

I suspect it's some kind of a ground loop between the Pi ground connected to the DRV8825 ground and the low pin connected to STEP. But how would that happen? Both of them are just the ground of the Pi. You don't need two ground wires (one from Rpi GND to DRV8825 ground) and another ground for the S...
by salvato
Wed Jul 22, 2020 5:51 pm
Forum: Automation, sensing and robotics
Topic: Erratic stepper motor movement with DRV8825 (Floating RPi ground?)
Replies: 8
Views: 503

Re: Erratic stepper motor movement with DRV8825 (Floating RPi ground?)

How long is the connection cable ?

You can try to use opto-couplers if the cable is too long
by salvato
Wed Jun 03, 2020 5:11 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

dsyleixa123 wrote: Are YOU able to change your code in the extra files to draw directly to a paint widget from out of the main program (mainwindow.cpp, mainwindow.ui)?
I'm afraid No.
by salvato
Wed Jun 03, 2020 4:39 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

To the best of my knowledge, you can't use directly the widgets available from the designer. You have to derive your classes and overload some functions. This could be a way but my knowledge of english is not good enough to explain how. Again I strongly suggest you to learn how to create your user i...
by salvato
Tue Jun 02, 2020 6:16 am
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

how can I fix that? Where is a boot option to restore by defaults ? Take your uSD card out of your raspberry mount on your PC open the /boot/config.txt (as root) find the line containing: dtoverlay=vc4-kms-v3d or dtoverlay=vc4-fkms-v3d and insert a # as the first character like this #dtoverlay=vc4-...
by salvato
Mon Jun 01, 2020 7:30 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

lots of slowly spinning circles.
this happen because opengl is not using the VGU by default you have to enable it on raspi-config
by salvato
Mon Jun 01, 2020 7:01 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

When you click "OK" on the "error" dialog Qt allow you to configure the new project an then load it into the editor without problems
by salvato
Mon Jun 01, 2020 6:48 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

libIEGL: failed to authenticate (??)

forget this message.

The qt version I use is qt5 as yours maybe a more updated one... so I don't understand the message you get when you try to run my program
by salvato
Mon Jun 01, 2020 6:25 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

Hi,
out of curiosity, what version of Qt are you using and on which Raspberry model ?

Gabriele
by salvato
Sun May 31, 2020 6:37 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

my last attempt:
give a look at :
https://doc.qt.io/qt-5/qpainter.html

Gabriele
by salvato
Sun May 31, 2020 3:51 pm
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

In a certain sense you are wrong. I too use the same qtcreator as you and if you clone the repository you will be able to compile, debug and run my program exactly as yours. No different qt version is used. You should try to put apart your worrying about your limited knowledge of programming with C+...
by salvato
Sun May 31, 2020 9:23 am
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

Try to get the last commented version I placed on github. I don't like the Qt designer and prefer to create the UI elements by myself like in ""window.cpp". In this way is easy to derive your class from Qt native classes and add your members and functionalities. Should be easy to follow the comments...
by salvato
Sun May 31, 2020 8:10 am
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

I've created for you a slimmed down version of the App.
https://github.com/salvato/2dpainting.git

Try to understand how the thing works... All the graphics is contained in the class "Helper"
which is called in the

Code: Select all

void GLWidget::paintEvent(QPaintEvent *event)
member.

Hope this help

Gabriele
by salvato
Sun May 31, 2020 7:06 am
Forum: C/C++
Topic: qt5 creator + designer: super simple graphic examples
Replies: 86
Views: 3997

Re: qt5 creator + designer: super simple graphic examples

Hi,
You can do 2D Graphics with OpenGL BUT OpenGL is mainly devoted to 3D.
OpenGL by itself is a complicated thing that require time to understand and
use. Are you ready to study tons of documents ?

Code: Select all

if (true) {
	try to start from here:
https://doc.qt.io/qt-5/qtopengl-2dpainting-example.html

Code: Select all

}
by salvato
Fri May 22, 2020 12:41 pm
Forum: Automation, sensing and robotics
Topic: Create DAC Amplifier
Replies: 3
Views: 266

Re: Create DAC Amplifier

I'm not convinced... anyway give a look at this: https://www.digikey.it/en/product-highlight/a/apex-microtechnology/pa12-pa12a-power-operational-amplifier?utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=Dynamic%20Search_EN_RLSA_Product_Cart&utm_term=&productid=&gclid=EAIaIQobChMIgL...
by salvato
Wed May 20, 2020 6:30 am
Forum: Automation, sensing and robotics
Topic: Create DAC Amplifier
Replies: 3
Views: 266

Re: Create DAC Amplifier

Usually to control (the speed of) a DC motor is best to use PWM otherwise, at low speed, the torque you get will be too low.

If you choose pwm you can use many different inexpensive modules like the L298 based ones.
by salvato
Sat Apr 25, 2020 12:27 pm
Forum: Troubleshooting
Topic: raspistill terminal command does nothing
Replies: 35
Views: 1044

Re: raspistill terminal command does nothing

just to add some noise...

1) Are you using the official Raspberry Camera ?

2 ) Is the cable correctly connected both to the camera and the Raspberry ?
by salvato
Sat Apr 25, 2020 12:15 pm
Forum: General discussion
Topic: Programs for everything...
Replies: 0
Views: 157

Programs for everything...

Hi all,

probably everyone knows already but for me is a new discover:
https://github.com/ControlEverythingCommunity

hope to help.
by salvato
Thu Apr 23, 2020 1:07 pm
Forum: General discussion
Topic: Reliable means of determining directional heading...
Replies: 83
Views: 2668

Re: Reliable means of determining directional heading...

Hi again, a few more thoughts... try to navigate in a more or less know environment in complete dark. How can you try to follow a given path ? You can use all your other senses but, probably, after a few steps your orientation is more or less lost. Try the same with few feeble led placed in known pl...
by salvato
Tue Apr 21, 2020 4:37 pm
Forum: General discussion
Topic: Reliable means of determining directional heading...
Replies: 83
Views: 2668

Re: Reliable means of determining directional heading...

Yes, it would be reasonable to think that you could figure it out, especially with a detailed and accurate map. I have not spent a lot of time trying yet as I see that as a "next step" in this process. My focus is to get things as accurate as possible to keep the amount of "checking" in real time w...
by salvato
Tue Apr 21, 2020 4:11 pm
Forum: General discussion
Topic: Reliable means of determining directional heading...
Replies: 83
Views: 2668

Re: Reliable means of determining directional heading...

... As of right now, the robot has: RPlidar sensor on the front, measuring a 190 degree sweep to check for objects in the path and in the "passing lanes" 8 IR distance sensors with 70" range capacity, there are 2 on each side of the robot A tape switch on the front bumper so that when all sensors m...

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