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by penguintutor
Fri Jan 04, 2019 12:02 pm
Forum: Networking and servers
Topic: Using RPi as AP to access files on RPi from pc or phone
Replies: 1
Views: 138

Re: Using RPi as AP to access files on RPi from pc or phone

I'd suggest using IP address for now, until you have got it working properly. You should also try with a PC to make sure it's working correctly prior to using a phone as phones have limited troubleshooting tools (unless installed separately), and phones may use smart-switch and so drop WiFi connecti...
by penguintutor
Fri Jan 04, 2019 10:50 am
Forum: General discussion
Topic: Looking for resources / new to the hardware aspect
Replies: 6
Views: 296

Re: Looking for resources / new to the hardware aspect

MOSFETs are switched based on voltage (actually charge) rather than current, so there is only a tiny current that will normally flow between the gate and source. The MOSFET it turned on by having a voltage at the gate that exceeds the threshold voltage. The maximum current that can be drawn does dep...
by penguintutor
Thu Jan 03, 2019 3:14 pm
Forum: Scratch
Topic: Scratch 3 Desktop Version for Raspberry Pi
Replies: 14
Views: 5906

Re: Scratch 3 Desktop Version for Raspberry Pi

I have used the online version in Raspbian (I used that during the Beta testing). It's not just taking Scratch offline (although that is one thing), but having the ability to access the GPIO which we have on Scratch 1.4 and Scratch 2. That is the killer feature allowing it to be used with physical c...
by penguintutor
Thu Jan 03, 2019 11:27 am
Forum: General discussion
Topic: Looking for resources / new to the hardware aspect
Replies: 6
Views: 296

Re: Looking for resources / new to the hardware aspect

The GPIO ports on the Raspberry Pi are low voltage & low current ports. If you just want to create one or two LEDs then you can connect them directly to the GPIO using a suitable resistor, but if you want to switch multiple LEDs then you may need to use a separate supply. (Sounds like you've worked ...
by penguintutor
Thu Jan 03, 2019 10:54 am
Forum: Python
Topic: use a webpage to edit areas of a script
Replies: 4
Views: 246

Re: use a webpage to edit areas of a script

Your question is very vague. What have you created so far? Have you tried searching for some tutorials that can help? Web Server Are you running a web server? If so try searching for how to run a script in your webserver and have that script take a value from a form submission and write that to a fi...
by penguintutor
Thu Jan 03, 2019 10:36 am
Forum: Python
Topic: Touchscreen Interface Programming....??
Replies: 5
Views: 404

Re: Touchscreen Interface Programming....??

For a simple interface then big buttons that need to be clicked with a mouse work well. I've created touchscreen apps using Pygame, Pygame Zero and through a webbrowser interface driven using a Python Bottle webserver. You just need to consider the size of the screen you are targetting and making su...
by penguintutor
Thu Jan 03, 2019 10:32 am
Forum: Scratch
Topic: Scratch 3 Desktop Version for Raspberry Pi
Replies: 14
Views: 5906

Scratch 3 Desktop Version for Raspberry Pi

Now that Scratch 3 has been released are there any plans for a Raspberry Pi (Linux) version of the Desktop version? Scratch 3 can be run through a browser today, but the desktop version is required for offline use and to support physical computing using the Raspberry Pi GPIO ports? If so is there an...
by penguintutor
Fri Feb 09, 2018 10:49 am
Forum: General discussion
Topic: Telephone and Raspberry Pi
Replies: 5
Views: 859

Re: Telephone and Raspberry Pi

First a disclaimer - always be legal! You may need to check what the law says about recording calls. It sounds like you should be okay with what you are planning, but even if recording your own calls you may have a legal obligation to warn others when you are recording the calls. Whether it's possi...
by penguintutor
Fri Feb 09, 2018 10:11 am
Forum: General discussion
Topic: Pi and Paintball
Replies: 1
Views: 280

Re: Pi and Paintball

I can't comment much about paintball. Last time I took part in a paintball I took a shot in the head which was incredibly painful! Showing a timer should be fairly straight forward. To create a view of the battlefield then I'd suggest something like pygame zero, which makes creating a GUI easier tha...
by penguintutor
Thu Feb 08, 2018 5:05 pm
Forum: General discussion
Topic: GPIO pin and button
Replies: 2
Views: 308

Re: GPIO pin and button

The GPIO pins operate differently depending upon whether they are configured as an input or an output. When using the GPIO pin as an output then they can provide a reasonable current (enough to light an LED with appropriate resistor), but when they are configured as an input they will not provide an...
by penguintutor
Fri Feb 02, 2018 2:12 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DH11 Sensor over longer distance
Replies: 2
Views: 689

Re: DH11 Sensor over longer distance

Presumably you are using the DHT11 - rather than DH11. That particular sensor only has a small range of around 20cm when run at 3.5V. If connecting to the GPIO 3.3V then that will likely drop off sooner. Using a 5V supply may not help either as you still need to use 3.3V for the pull-up resistor to ...
by penguintutor
Fri Feb 02, 2018 1:34 pm
Forum: General discussion
Topic: Difference Running program from Python Shell or Terminal
Replies: 3
Views: 607

Re: Difference Running program from Python Shell or Terminal

Any manner to change it defaulting Python 3 as main Shell ?? Is that really what you want to do, as that will break it when you run from the shell as well as from the python shell? If so then the version of python that runs is based on a link in /usr/bin - so that when you run /usr/bin/python it ca...
by penguintutor
Fri Feb 02, 2018 1:06 pm
Forum: General discussion
Topic: PiClock help
Replies: 2
Views: 346

Re: PiClock help

There is nothing in the documentation that provides an option to turn-off the fullscreen, but it should be possible by modifying the source code. It looks like you need to edit the file PiClock/PyQtPiClock.py Near the end of the file is a line: w.showFullScreen() remove that line by commenting it ou...
by penguintutor
Fri Feb 02, 2018 12:49 pm
Forum: General discussion
Topic: octoprint exceeding cpu power of old pi B ?
Replies: 7
Views: 1860

Re: octoprint exceeding cpu power of old pi B ?

I've only run Octoprint on a Pi 3.

Considering a Pi3 costs about the same as 2 reels of PLA then it may be worth upgrading if you are struggling with performance running it on older hardware.

Although saying that it sounds like it may be your 3D printer as much as a problem with Octoprint.
by penguintutor
Fri Feb 02, 2018 12:36 pm
Forum: General discussion
Topic: How to store data from OpenCV to cloud?
Replies: 1
Views: 239

Re: How to store data from OpenCV to cloud?

OpenCV is a library for processing image data. The cloud in this case is anything that's on the Internet. So is that just the same as saying how can I put some kind of data on the Internet? If so then you could either make your Pi accessible from the Internet (port forwarding on your local router an...
by penguintutor
Sat Sep 02, 2017 7:48 am
Forum: Python
Topic: RF transmission and receiving using python
Replies: 3
Views: 905

Re: RF transmission and receiving using python

I'm not familiar with 433Utils, but it looks like it's a basic library for sending short command codes rather than transmitting data. It looks like it sends integer values as the command codes. Presumably you could use that to send whatever data you wanted as long as the client and server are talkin...
by penguintutor
Fri Sep 01, 2017 8:34 pm
Forum: Python
Topic: Python program results in system unstable - Possible Bottle mutex problem?
Replies: 0
Views: 264

Python program results in system unstable - Possible Bottle mutex problem?

Has anyone experienced any issues when using Python Bottle which results in extremely poor performance and/or system instability? I have a problem with a program I'm writing using Python3. It's a fairly complex bit of code involving Python Tk, which uses python urllib to connect to a webserver using...
by penguintutor
Thu Jun 16, 2016 3:47 pm
Forum: Beginners
Topic: Auto type "vncserver :1" on reboot
Replies: 6
Views: 1361

Re: Auto type "vncserver :1" on reboot

As an alternative I've written a guide to starting tightvnc at startup, it uses a systemd startup file, which is the same way that other services are started on the Raspberry Pi.

http://www.penguintutor.com/linux/tightvnc
by penguintutor
Thu Jun 16, 2016 2:06 pm
Forum: Troubleshooting
Topic: noobs 1.9 build
Replies: 12
Views: 3226

Re: noobs 1.9 build

It could be a faulty SD card, but you may get similar issues if you don't have enough power. Make sure that you have a decent power supply able to provide at least 1A.
by penguintutor
Tue Jun 14, 2016 2:16 pm
Forum: Troubleshooting
Topic: LED strip on USB hub
Replies: 2
Views: 799

Re: LED strip on USB hub

Could the LED strip be trying to pull more than the 720mA? I've seen other types of LED bulbs where they have quoted the amount of power used by the LED bulbs, but not included power lost in the resistors included in the lights. This could mean that it is pulling more power than the USB hub is able ...
by penguintutor
Tue Jun 14, 2016 2:02 pm
Forum: Troubleshooting
Topic: noobs 1.9 build
Replies: 12
Views: 3226

Re: noobs 1.9 build

It looks like OpenELEC has been replaced on NOOBS with LibreELEC. See more about LibreELEC here https://libreelec.tv/about/ It sounds like some of the developers from OpenELEC have moved to LibreELEC, but both projects are being developed. Other than that I don't know much about the reasoning / poli...
by penguintutor
Tue Jun 14, 2016 1:50 pm
Forum: Beginners
Topic: How d I build a rc raspberry pi robot?
Replies: 3
Views: 707

Re: How d I build a rc raspberry pi robot?

I have written a guide at: http://www.penguintutor.com/electronics/rpirobot

It was written before GPIO Zero which could be used to make the code a bit easier to learn, but it should give you a good idea of how to get started.
by penguintutor
Tue Jun 14, 2016 1:46 pm
Forum: Beginners
Topic: the most irritating PI Zero question
Replies: 16
Views: 2444

Re: the most irritating question

See the following announcement and get ordering now...
http://us7.campaign-archive2.com/?u=219 ... a72f8a68f3

Or I'm guessing that Pimoroni may have some in tomorrow (usually Wednesday morning that Pi Zeros go on sale).
by penguintutor
Tue Jun 14, 2016 1:31 pm
Forum: Beginners
Topic: Power model A+ with doorbell tranformer
Replies: 5
Views: 896

Re: Power model A+ with doorbell tranformer

I'm not aware of anything you can buy that will do what you want. It is possible to make one, but would need a bit of electronics. As the transformer is AC and the Raspberry Pi is DC then you will need a bridge rectifier circuit. You would need to connect a bridge rectifier to the 8V output of the t...
by penguintutor
Tue Jun 14, 2016 1:17 pm
Forum: Beginners
Topic: Temperature controlled slowcooker: What to Buy?
Replies: 3
Views: 1317

Re: Temperature controlled slowcooker: What to Buy?

There's a write-up on a Sous-Vide project at: https://www.raspberrypi.org/blog/sous-vide-cooking-with-the-wolfram-language/ I believe Rachel (from the Foundation) also created a Sous-vide cooker using Energenie remote control sockets. Essentially you need Input In addition to the thermocouple then y...

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