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by hippy
Tue Jan 22, 2019 1:33 pm
Forum: General discussion
Topic: Control Fan by switching USB port on and off
Replies: 8
Views: 128

Re: Control Fan by switching USB port on and off

It cannot be done this way. The Pi does not have individual USB power control; it's all or nothing, all four ports powered or none. I seem to recall reading an article about reducing power consumption which suggested that on the 3B+ at least, you can disable the Ethernet and just two of the 4 USB s...
by hippy
Tue Jan 22, 2019 1:38 am
Forum: Beginners
Topic: Connecting two Pis via GPIO
Replies: 3
Views: 83

Re: Connecting two Pis via GPIO

is it safe to connect two Pis together (Zero W and 3B+) via GPIO if all of their pins are connected 1:1? No; you will be shorting power rails together, outputs to outputs. You can power one Pi from another, and if you want to have the Pi's communicate with each other 'via GPIO pins' you can cross-w...
by hippy
Tue Jan 22, 2019 1:32 am
Forum: General discussion
Topic: copyright/patent
Replies: 7
Views: 249

Re: copyright/patent

klricks wrote:
Mon Jan 21, 2019 2:15 pm
Only the RPi ZERO models can do 'gadget' mode.
I haven't personally tried it but I am led to believe the A, A+ and 3A+ can also run in gadget mode though one needs to configure the software to force that mode and make or obtain an appropriate cable.
by hippy
Tue Jan 22, 2019 1:25 am
Forum: Python
Topic: Learn Python 2 or 3 and how?
Replies: 12
Views: 197

Re: Learn Python 2 or 3 and how?

In eleven months, ten days, 4hours you won't get a choice. Not true at all. The intention is to stop supporting and maintaining Python 2. People will still be able to use Python 2 and choose to program in Python 2 if they want to. Programs written for Python 2 won't suddenly stop working, Python 2 ...
by hippy
Tue Jan 22, 2019 1:18 am
Forum: Automation, sensing and robotics
Topic: 2 LED wiring
Replies: 10
Views: 158

Re: 2 LED wiring

You can use one resistor if only one LED will be on at a time . Whenever I've tried that, all cathodes commoned through a single resistor to 0V it has worked for me. It's handy for wiring up 7-Segment displays. The only problem is, the more LED's are lit, the dimmer each becomes. If you want to pow...
by hippy
Tue Jan 22, 2019 1:06 am
Forum: General discussion
Topic: Control Fan by switching USB port on and off
Replies: 8
Views: 128

Re: Control Fan by switching USB port on and off

In this Script I want to write a command which turns on a specific USB port and the USB port powers the fans. It cannot be done this way. The Pi does not have individual USB power control; it's all or nothing, all four ports powered or none. You need GPIO lines to switch relays or a FET to turn pow...
by hippy
Mon Jan 21, 2019 9:43 pm
Forum: Beginners
Topic: Solution to use same keyboard and mouse as desktop PC?
Replies: 13
Views: 295

Re: Solution to use same keyboard and mouse as desktop PC?

Got round to building my DIY KVM over the weekend - £2.00 - Two-off, four-port USB hubs £0.20 - Two-pole two-way slide switch £6.00 - Three-way HDMI selector ------ £8.20 Two hubs because I wanted two USB plugs. Soldered one hub into the other so it's a seven port hub now. Seems to be working well. ...
by hippy
Mon Jan 21, 2019 9:31 pm
Forum: General discussion
Topic: Features for future Pi, voltage/current reporting.
Replies: 29
Views: 443

Re: Features for future Pi? (suggestion)

the PMIC just sets a line high (or low?) when the undervoltage is detected. It doesn't present the actual voltage to the SoC. The MxL7704 PMIC doesn't report its voltage input, but it does have two unused ADC inputs, one of which could perhaps be used to monitor the voltage input. That might be zer...
by hippy
Mon Jan 21, 2019 5:36 pm
Forum: General discussion
Topic: usb_mass_storage
Replies: 7
Views: 218

Re: usb_mass_storage

Now, the problem is some times when usb_mass_storage mounted on windows/Linux PC(host) shows read only, and i am not able to copy files....How to solve this It seems there are potentially two explanations for this - Either the Pi Gadget isn't telling the PC that its MSD is writeable when the PC det...
by hippy
Sun Jan 20, 2019 10:26 pm
Forum: HATs and other add-ons
Topic: Pi TV Hat questions
Replies: 6
Views: 1792

Re: Pi TV Hat questions

Did anybody discover whether multiple TV hats can be connected to the GPIO of the same Pi? They can't work because both would use the same SPI chip select/chip enable pin unless you can change the hardware (which isn't possible for a hobbyist). I don't see why it isn't possible for a hobyist. Hardw...
by hippy
Sun Jan 20, 2019 3:57 pm
Forum: Troubleshooting
Topic: Boot Problems
Replies: 10
Views: 212

Re: Boot Problems

This made me realize that the 5v and the 3v3 are really close. I hate to criticize the designers of the Rpi which I absolutely love but I think this is kind of a design flaw. Pins in a multi-way header are always going to be close to each other with the potential for shorting them out when probing ...
by hippy
Sun Jan 20, 2019 3:46 pm
Forum: HATs and other add-ons
Topic: Can 24V passive PoE power Raspberry Pi PoE HAT?
Replies: 8
Views: 168

Re: Can 24V passive PoE power Raspberry Pi PoE HAT?

If the PoE HAT uses the MP8007, as I believe it does, then that is rated for 0V-56V operation, so applying 24V across VDD/VSS should not damage it. The datasheet appears to indicate the 'on range' requires 37V to 57V so 24V may not be enough to enable output. It also seems that the power provider ne...
by hippy
Sat Jan 19, 2019 2:13 pm
Forum: Python
Topic: python tcp client script help
Replies: 9
Views: 436

Re: python tcp client script help

champ1 wrote:
Sat Jan 19, 2019 12:27 pm
ok do you like ...
Better, but you will get an "undefined data2 variable" or similar error when you hit the 'if' test the first time because 'data2' has not been initialised before then.
by hippy
Sat Jan 19, 2019 12:20 am
Forum: Troubleshooting
Topic: Raspberry pi 3.5" screen issue (unable to dim or turn off via command line)
Replies: 3
Views: 88

Re: Raspberry pi 3.5" screen issue (unable to dim or turn off via command line)

^ What he said. A lot of these LCD's have backlights which are wired such that they are on whenever the power is applied and there's no easy way to turn them off without adding your own intervening hardware. And, if wanting to do dimming, other than writing darker pixels to the screen, you could onl...
by hippy
Sat Jan 19, 2019 12:09 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Hardware RESET of device with backlight.
Replies: 3
Views: 98

Re: Hardware RESET of device with backlight.

I have limited schematic and I should be able to read the RESET. I was just hoping to do that in software. Isn't that RESET a one way signal, from the Pi to the LCD, to put it into a known starting condition when asserted ? I'm not sure how you mean about reading it. It may be a help if you could e...
by hippy
Fri Jan 18, 2019 11:55 pm
Forum: General discussion
Topic: usb_mass_storage
Replies: 7
Views: 218

Re: usb_mass_storage

That's bad, really, really bad. Not the error, what you appear to be doing. If you ever get the time; would you care writing up some notes as to how it should be done, or pointing to a good tutorial if you know of one, or have already written it, as you seem to know more than most about the intrica...
by hippy
Fri Jan 18, 2019 9:17 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Hardware RESET of device with backlight.
Replies: 3
Views: 98

Re: Hardware RESET of device with backlight.

If you have a LCD or other "lit up " device and clear - set low , ground - the RESET pin does it shuts down the backlight ? Probably not but the device's datasheet or cicruit diagram should give you a definitive answer. If it's some sort of clone of the equivalent Waveshare LCD that has a backlight...
by hippy
Fri Jan 18, 2019 9:11 pm
Forum: Raspbian
Topic: New user made a terrible mistake ... Help?
Replies: 10
Views: 289

Re: New user made a terrible mistake ... Help?

It can be worth getting two SD Cards. One which you can boot and try things out on before applying the same to your important system which has stuff which is a pain to setup.

And keep a note of what you installed and tweaked just in case you do have to do it again.
by hippy
Fri Jan 18, 2019 9:04 pm
Forum: Troubleshooting
Topic: Pi 3B+ stops working
Replies: 28
Views: 963

Re: Pi 3B+ stops working

The problem with a dead PMIC is that you would likely have to supply all the other voltages it generates as well. Just connecting 3V3 isn't going to work. Also there's more than one 3V3 supply and we don't know what uses which because there are no full circuit diagrams. We also don't know the PMIC i...
by hippy
Fri Jan 18, 2019 8:10 pm
Forum: Scratch
Topic: Scratch 3
Replies: 19
Views: 8331

Re: Scratch 3

Vivaldi 2.2 seems to support WebGL out of the box. Using 75%-85% CPU when idling. Better than previous 1.13, but not as good as Chromium.
by hippy
Fri Jan 18, 2019 7:54 pm
Forum: Scratch
Topic: Scratch 3
Replies: 19
Views: 8331

Re: Scratch 3

fruitoftheloom wrote:
Fri Jan 18, 2019 7:40 pm
hippy wrote:
Fri Jan 18, 2019 7:37 pm
Downloaded and installed the latest (stable_1.13.1008.34-1)
Version 2.2 is for ARM :?
Looks like their Pi specific page is out of date -

https://vivaldi.com/blog/vivaldi-for-raspberry-pi/

I'll try 2.2 once I figure out how to uninstall what I have.
by hippy
Fri Jan 18, 2019 7:37 pm
Forum: Scratch
Topic: Scratch 3
Replies: 19
Views: 8331

Re: Scratch 3

Try Vivaldi Browser for ARM ? https://vivaldi.com/download/ Downloaded and installed the latest (stable_1.13.1008.34-1); "Does not support WebGL", so that's a no go. Added: enter 'vivaldi://flags' as the URL and there's an Experimental WebGL Extension option which can be enabled which then lets Scr...
by hippy
Fri Jan 18, 2019 6:55 pm
Forum: Scratch
Topic: Scratch 3
Replies: 19
Views: 8331

Re: Scratch 3

Brand new RPi 3b+ New install of Noobs - updated and upgraded. Try Scratch 3.0 - CPU maxes out and stage never appears. Basically no use. Is this a problem using Chromium? Any other browser proving successful? This is a serious setback when trying to make life easy for young/new users. I just tried...
by hippy
Fri Jan 18, 2019 6:25 pm
Forum: Troubleshooting
Topic: Boot Problems
Replies: 10
Views: 212

Re: Boot Problems

They are both failed 3B+ devices so check if 3V3 is present on the Pi board. If not; they are dead, and it's pointless worrying further - follow the Boot Problem Sticky advice and contact your sellers for replacements.
by hippy
Fri Jan 18, 2019 1:14 am
Forum: Beginners
Topic: Solution to use same keyboard and mouse as desktop PC?
Replies: 13
Views: 295

Re: Solution to use same keyboard and mouse as desktop PC?

If one is on a budget, a multi-pole multi-way switch and some hacked USB extension cables could work, switching one hub with its mouse and keyboard to any number of Pi's, add a cheap HDMI selector and you are sorted. It might be better to use a powered hub or powered from just one Pi so you don't ha...

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