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by PiGraham
Fri Jan 17, 2020 10:26 am
Forum: General discussion
Topic: Sending acoustic sound to the cloud
Replies: 3
Views: 100

Re: Sending acoustic sound to the cloud

Hello, I am a newbie. I would like to send recorded audio on the raspberry pi to the cloud. The first thing you need is an interface to capture audio. The Pi has no audio in channel. You can use a "USB soundcard" and a an analogue microphone. You can use a USB microphone You can use a web cam with ...
by PiGraham
Wed Jan 01, 2020 2:30 pm
Forum: Python
Topic: How to synchronize data on txt files between raspberrys
Replies: 16
Views: 510

Re: How to synchronize data on txt files between raspberrys

HI , I don't understand well your question, I run python in raspberry pi : I open the terminal and I write 'sudo idle' to open the shell window and then I open the python file and run it.... That answers my question. You are running python with sudo, It would probably work OK is you dropped the sud...
by PiGraham
Tue Dec 31, 2019 9:27 am
Forum: Python
Topic: How to synchronize data on txt files between raspberrys
Replies: 16
Views: 510

Re: How to synchronize data on txt files between raspberrys

ghp wrote:
Tue Dec 31, 2019 8:01 am
Did you remove the sudo from

Code: Select all

subprocess.call("sudo scp ...
??
Is Python being run with sudo? That used to b necessary to use gpio and will show in some examples and tutorials.
Would that affect ssh keys?
by PiGraham
Mon Dec 23, 2019 3:16 pm
Forum: General discussion
Topic: Is there a Raspberry Pi 4 "Slim" version?
Replies: 27
Views: 1511

Re: Is there a Raspberry Pi 4 "Slim" version?

Cutting the plastic, allows you to remove the pins one at a time via heating the solder until it flows and then gently pulling the pins out, one at a time. You can pull the pins one at a time while heating the solder WITHOUT removing the plastic strip. The hot pin will pull through it fairly easily...
by PiGraham
Thu Dec 19, 2019 8:06 am
Forum: General discussion
Topic: Two ethernet ports
Replies: 15
Views: 694

Re: Two ethernet ports

I think there is consensus here that USB3 Ethernet adaptor is the the favourite option. I did come across this which may be an issue, but still doesn't suggest any other option would be better. If you're planning to use the second ethernet connection as a WAN port, the problem you're going to run in...
by PiGraham
Wed Dec 18, 2019 5:22 pm
Forum: Camera board
Topic: One camera, 2 preview windows. Is this possible?
Replies: 9
Views: 743

Re: One camera, 2 preview windows. Is this possible?

I'm a total noob with this, but I have a regular RPi 3 B+ with the standard camera module. I can get the preview to work just fine with one window, but is there any way to do it such that there are two preview windows side by side? (Similar to VR output) I'm curious. Why do you want to do that? Per...
by PiGraham
Tue Dec 17, 2019 3:41 pm
Forum: General discussion
Topic: Two ethernet ports
Replies: 15
Views: 694

Re: Two ethernet ports

I should think you would get the best performance using a network switch. The Ethernet on Pi4B is integrated with the SOC for a fast connection. USB3.0 will be slower and anything on GPIO will be very slow in comparison, I think. If you aren't so concerned with performance then a USB3.0 adaptor woul...
by PiGraham
Fri Dec 06, 2019 8:49 am
Forum: Compute Module
Topic: What else is there besides Raspberry Pi..?
Replies: 19
Views: 1069

Re: What else is there besides Raspberry Pi..?

This is the core of the request and the big reason it's not for RPi: But of course for snits and giggles I want to do it myself. But here's the stumbling point: I wish it to be a full Android device. ... compatible with Android, the Google Play Store, and the zillion apps on there. If you want full ...
by PiGraham
Thu Dec 05, 2019 4:55 pm
Forum: Compute Module
Topic: What else is there besides Raspberry Pi..?
Replies: 19
Views: 1069

Re: What else is there besides Raspberry Pi..?

Try searching for "system on module android"
by PiGraham
Tue Dec 03, 2019 10:56 am
Forum: Troubleshooting
Topic: GUI without Desktop
Replies: 3
Views: 161

Re: GUI without Desktop

221373 wrote:
Tue Dec 03, 2019 10:14 am
Hi I have program which run and open via Qt application. There is a kind of user interface in window to visualize sensors read and some of buttons to implement some actions.
Maybe this will help to get Qt working on framebuffer without X
https://doc.qt.io/archives/qt-4.8/qvfb.html
by PiGraham
Tue Dec 03, 2019 10:00 am
Forum: Troubleshooting
Topic: GUI without Desktop
Replies: 3
Views: 161

Re: GUI without Desktop

It might help define the problem better if you say what sort of GUI you want? windows, icons buttons and menus?
Something more like a game GUI?

I think you can work without X using PyGame and maybe tkinter.

This may be useful
http://www.karoltomala.com/blog/?p=679
by PiGraham
Thu Nov 21, 2019 10:34 am
Forum: General discussion
Topic: magnetometer for detecting objects
Replies: 4
Views: 334

Re: magnetometer for detecting objects

It also has a fairly sensitive accelerometer, but I wasn't able to detect the ground vibrations of passing cars at 8 metres with that either. It seems MEMS accelerometers could detect traffic if they were close enough, but maybe not suited to remote sensing over many metres. https://www.kickstarter...
by PiGraham
Tue Nov 19, 2019 11:11 am
Forum: Beginners
Topic: Maybe a Dumb Question, But How Can I Lock Down an App?
Replies: 4
Views: 238

Re: Maybe a Dumb Question, But How Can I Lock Down an App?

Thanks W. H. Heydt and rpdom for your prompt replies. I did not receive notification that my post had been approved, nor did I receive any notification of your replies. Good thing I decided to check! :) So maybe my first post did not go quite as planned. My main concern was with the capability of t...
by PiGraham
Tue Nov 12, 2019 2:03 pm
Forum: Wanted
Topic: Engineering Project - Need Help
Replies: 8
Views: 598

Re: Engineering Project - Need Help

OK here’s what I am looking for. A basic knob switch, 4 settings plus off/on switch. Each setting would control a speed to make the light dim up, hold, dim down on a specific timed setting. I'm hoping to hire a hobbiest or student wanting to learn What sort of light? What is the the dimmer for? Is ...
by PiGraham
Tue Nov 12, 2019 12:31 pm
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

You are in effect asking for indoor GPS, which is not a trivial task at all. It's quite difficult. I'm not asking for anything. The OP asks for a hide-and-seek detector system. From a cursory test of BT using RSSI and noting numerous comments on the ineffectiveness of such apps I'm sceptical whethe...
by PiGraham
Tue Nov 12, 2019 9:48 am
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

something to indicate to the user how close (how high/low the RSSI is) you are to the beacon. /Mogens Does that really work? As I mentioned the two Bluetooth finder apps I tried seemed all but useless for locating Bluetooth devices. Maybe it would work better if there were some fixed beacons in kno...
by PiGraham
Tue Nov 12, 2019 9:41 am
Forum: Automation, sensing and robotics
Topic: Distances of two different points in x y z coordinates
Replies: 23
Views: 1890

Re: Distances of two different points in x y z coordinates

I don't think ". I have no restrictions on that device." means "money no object". Still, this is cool if can afford it. Measure whatever you want. https://www.youtube.com/watch?v=KUdbrFOJlO0 Or https://www.youtube.com/watch?v=aq4NLmiJHwk I need to calculate distance between 2 spesific objects (Actu...
by PiGraham
Mon Nov 11, 2019 4:37 pm
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

The big advantage of buying the beacon tags is that they integrate a battery into a neat case and last for a long time. Battery life is over 3 year on default setting. battery CR3032 battery https://www.banggood.com/Waterproof-BBeacon-Module-Module-Card-with-Eddystone-and-Beacon-for-Indoor-Navigatio...
by PiGraham
Mon Nov 11, 2019 8:08 am
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

Searching for "long range uhf rfid reader raspberry pi" gives a few results worth checking out. Nothing specific that might suit this application? There are things like this: https://www.amazon.co.uk/reader-vehicle-parking-application-meters/dp/B018EFLJJI which claim 3 to 5 metres reading range but...
by PiGraham
Sun Nov 10, 2019 9:08 pm
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

deepo wrote:
Sun Nov 10, 2019 6:58 pm
ranges below 2 meters is the norm.
I'd think you can get 1 meter detection range with modest equipment.
The cheap maker kit I've seen is a range of a few centimetres (~2cm)

Can you give examples of kit that works at more than 10cm?
by PiGraham
Sat Nov 09, 2019 4:13 pm
Forum: Automation, sensing and robotics
Topic: Distances of two different points in x y z coordinates
Replies: 23
Views: 1890

Re: Distances of two different points in x y z coordinates

Certainly that sort of 3D from stereo can be done.
As with any triangulation method the accuracy reduces as the separation reduces and the angle becomes very acute.
I think there's a tradeoff because wider separation improves the angle but also changes the view which can make feature matching harder.
by PiGraham
Sat Nov 09, 2019 10:35 am
Forum: Automation, sensing and robotics
Topic: Distances of two different points in x y z coordinates
Replies: 23
Views: 1890

Re: Distances of two different points in x y z coordinates

If it has to be cheap you could try 2 cameras, probably usb so 2 will work on a pi, and determine the distances to the points, from the difference between the images after you have calibrated. You could then use my earlier method with measured angles. Good point. If two cameras are rigidly mounted ...
by PiGraham
Fri Nov 08, 2019 5:06 pm
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

https://gaorfid.com/product/reader-active-usb-receiver-2-45-ghz-rfid/ 20m range used with active tags https://gaorfid.com/devices/rfid-tags-by-frequencies/active-2-45-ghz-rfid-tags/ Or something from eBay https://www.ebay.co.uk/itm/Active-RFID-Electronic-Tag-Reader-Undervoltage-reminder-ABS-For-Navi...
by PiGraham
Fri Nov 08, 2019 1:53 pm
Forum: Automation, sensing and robotics
Topic: Distances of two different points in x y z coordinates
Replies: 23
Views: 1890

Re: Distances of two different points in x y z coordinates

I don't think ". I have no restrictions on that device." means "money no object".

Still, this is cool if can afford it. Measure whatever you want.

https://www.youtube.com/watch?v=KUdbrFOJlO0

Or

https://www.youtube.com/watch?v=aq4NLmiJHwk
by PiGraham
Fri Nov 08, 2019 11:22 am
Forum: Other projects
Topic: Wireless Distance Sensing?
Replies: 38
Views: 2725

Re: Wireless Distance Sensing?

This claims to be BT5.0 Eddystone beacon in a watch format. 1 yr battery life
https://www.amazon.co.uk/JINOU-OEM-Prog ... B07HQ9DJKG

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