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by davidcoton
Sat Jun 15, 2019 9:25 pm
Forum: General discussion
Topic: Supplying 5v power to RPi & 120VAC to relays
Replies: 2
Views: 55

Re: Supplying 5v power to RPi & 120VAC to relays

If you are creating a commercial project powered fom mains (other than a bought-in PSU), you need to take advice from a manufacturer or consultant familiar with your local product legislation. Here be dragons. You also need to check that you can meet the license requirements of all the installed sof...
by davidcoton
Wed Jun 12, 2019 10:13 pm
Forum: Troubleshooting
Topic: Fresh Stretch install - WiFi not working
Replies: 6
Views: 125

Re: Fresh Stretch install - WiFi not working

/etc/wpa_supplican/wpa_supplicant.conf contains what it should, in fact identical to the Wheezy vertion. What gives? Since Wheezy, wpa_supplicant has aquired an extra line defining the country, so as to enforce regional rules on WiFi channels. Does your version contain that? It might help to post t...
by davidcoton
Wed Jun 12, 2019 6:35 pm
Forum: General discussion
Topic: [Solved] Would the AC/DC adapter provided in the URL be enough for the PI 3b?
Replies: 5
Views: 172

Re: Would the AC/DC adapter provided in the URL be enough for the PI 3b?

Of course it will.
It's the "official" Raspberry Pi PSU, designed precisely for the purpose of powering Pis.
by davidcoton
Wed Jun 12, 2019 12:42 pm
Forum: Troubleshooting
Topic: wlan0: Not associated
Replies: 34
Views: 468

Re: wlan0: Not associated

ps -A | grep 'wpa' 502 ? 00:00:00 wpa_supplicant [email protected]:~ $ 379 ? 00:00:00 wpa_supplicant bash: 379: command not found sudo kill -9 379 Not sure if I should continue with the next command you asked me to put in as I think the second one could be teh problem. If you think I should put in las...
by davidcoton
Wed Jun 12, 2019 9:04 am
Forum: General discussion
Topic: Running an RPI outside?
Replies: 12
Views: 295

Re: Running an RPI outside?

To back up the info above: You MUST use an RCD at the source of an outdoor mains supply. You should look for a commercial IP67 enclosure for all the mains components. With care and a large case you can put the Pi in there too. Don't forget the drain hole -- no bigger than 2mm diameter, though, to st...
by davidcoton
Tue Jun 11, 2019 8:18 pm
Forum: General discussion
Topic: Toggle switch question?
Replies: 4
Views: 126

Re: Toggle switch question?

The diagram you show is a 2 pole 2 way (2P2W) or 2 pole changeover (2PCO) switch, which is extremely common. It can also be referred to as 2 pole "on-on". Edit: as noted by other contributors below, "2" can be "D" for double, and "W" can be "T" for throw, as in DPDT. 4 pole would have a total of 12 ...
by davidcoton
Tue Jun 11, 2019 8:58 am
Forum: Beginners
Topic: Is reboot safe?
Replies: 17
Views: 395

Re: Is reboot safe?

This sort of situation rarely occurs, typically when upgrading from one release to another (jessie to stretch, or stretch to buster), but as the general Raspbian way seems to be "start again with a new download", you'll almost never hit this scenario. While it occurs rarely it depends only on packa...
by davidcoton
Sun Jun 09, 2019 4:33 pm
Forum: General discussion
Topic: Packages installing in wrong folder in Raspberry pi 3
Replies: 5
Views: 213

Re: Packages installing in wrong folder in Raspberry pi 3

How did you install them? What commands did you use?
by davidcoton
Thu Jun 06, 2019 5:04 pm
Forum: Troubleshooting
Topic: Pi Zero W Heating Rapidly and Won't Boot
Replies: 5
Views: 382

Re: Pi Zero W Heating Rapidly and Won't Boot

Jake Scott wrote:
Thu Jun 06, 2019 12:57 pm
Is the heating a common error??
No, but not unheard of either.
Jake Scott wrote:
Thu Jun 06, 2019 12:57 pm
Can bad soldering kill a zero??
Yes, easily.
by davidcoton
Thu Jun 06, 2019 4:37 pm
Forum: General discussion
Topic: Multiple Frame buffer beta testers wanted
Replies: 354
Views: 38514

Re: Multiple Frame buffer beta testers wanted

jamesh wrote:
Thu Jun 06, 2019 1:35 pm
nothing is concrete.
Have you tried a concrete frame buffer? :lol:
by davidcoton
Wed Jun 05, 2019 11:21 pm
Forum: General programming discussion
Topic: A Final Fibonacci Challenge
Replies: 500
Views: 12801

Re: A Final Fibonacci Challenge

I think fibo_phi is printing the final result as a Decimal type after rounding the fractional part to the nearest integer. Although the result quacks like a duck, the giveaway is that it prints much faster. If you don't mind the colour pink, see also http://www.pythonlake.com/python/decimal/decimal...
by davidcoton
Wed Jun 05, 2019 11:06 pm
Forum: Beginners
Topic: Error when attempting to format new SD card.
Replies: 34
Views: 612

Re: Error when attempting to format new SD card.

The context is that I have the micro SD card (in an adapter) in the card slot on my laptop. ... It's the largest capacity SD card I've ever had (32 GB) so it may be that my card reader can't handle that size of card. So, what capacity cards have worked in the same laptop slot? What is the marking o...
by davidcoton
Wed Jun 05, 2019 5:32 pm
Forum: General discussion
Topic: Interfacing Raspberry pi with EFB-REV1
Replies: 6
Views: 167

Re: Interfacing Raspberry pi with EFB-REV1

Rogger-78 wrote:
Wed Jun 05, 2019 1:23 pm
does RPi suport any LoRA gateway which means multiple EFB-REV1 send their status to single RPi over loRA
One possibility.
It's quicker to Google such things than ask here. You'll also get more possibilities.
by davidcoton
Tue Jun 04, 2019 11:03 pm
Forum: Troubleshooting
Topic: Failed to execute child process ".usr.bin.lxterminal" (No such file or directory)
Replies: 8
Views: 228

Re: Failed to execute child process ".usr.bin.lxterminal" (No such file or directory)

Raspbian is not Arch. Why were you trying to follow instructions on an Arch-related Reddit? (I don't know if that's the reason for your problem, but it may well be.)
by davidcoton
Tue Jun 04, 2019 8:29 pm
Forum: Troubleshooting
Topic: 7" touchscreen not working, tried everything I could think of
Replies: 2
Views: 70

Re: 7" touchscreen not working, tried everything I could think of

It would also help to know how you are powering the Pi and screen.
by davidcoton
Tue Jun 04, 2019 8:04 pm
Forum: General discussion
Topic: Self sailing boat
Replies: 9
Views: 283

Re: Self sailing boat

Will there be one program that processes everything or several for different motors ect. I don't think you can decide that so early in the project. First you need to know what the system should do (specification), then you can begin to work out how it does it. My gut feeling (which may be wrong) is...
by davidcoton
Tue Jun 04, 2019 4:02 pm
Forum: Beginners
Topic: Short blink/long pause LED with gpio zero
Replies: 8
Views: 217

Re: Short blink/long pause LED with gpio zero

Deleted 'cos no longer relevant.
by davidcoton
Tue Jun 04, 2019 3:57 pm
Forum: Beginners
Topic: Need 4 inputs to trigger 4 outputs.
Replies: 6
Views: 146

Re: Need 4 inputs to trigger 4 outputs.

No world dominating secret projects folks, sorry to disappoint y'all. I want a simple solar sun tracker. 4 sensors correspond to vertical and horizontal axis. What I want is when any one sensor exceeds water the Pi input triggering threshold is, e.g. 6v, it outputs 5+v to trigger a small relay whic...
by davidcoton
Tue Jun 04, 2019 3:47 pm
Forum: Beginners
Topic: Short blink/long pause LED with gpio zero
Replies: 8
Views: 217

Re: Short blink/long pause LED with gpio zero

for a 0.5 second flash once every 2 seconds then from gpiozero import LED from time import sleep red = LED(17) while True: red.on() sleep(0.5) red.off() sleep(2) [pedant] That will give a 0.5s flash every 2.5s (0.5 on, 2.0 off) For 0.5s flash every 2.0s use 0.5 on, 1.5 off [/pedant] But better to u...
by davidcoton
Tue Jun 04, 2019 3:10 pm
Forum: General discussion
Topic: Self sailing boat
Replies: 9
Views: 283

Re: Self sailing boat

Thanks appreciate the reply very helpful as before I had no idea where to start How do you eat an elephant? One bite at a time. +1 I, too, think you will need to start with smaller projects, building up to your goal. Buy a Pi starter kit, possibly one that includes various sensors and output device...
by davidcoton
Mon Jun 03, 2019 10:50 pm
Forum: General programming discussion
Topic: A Final Fibonacci Challenge
Replies: 500
Views: 12801

Re: A Final Fibonacci Challenge

Do you have a place were you have the 1 millions digit from fibo(4784969). I want to compare yours against mine to be sure that all digits are the same!. I think that you are using double value. Then you have an estimation of the Fibonacci and not the exact value. This is why I'm using the Decimal ...
by davidcoton
Mon Jun 03, 2019 9:01 pm
Forum: Beginners
Topic: How to hookup battery pack to a servo?
Replies: 8
Views: 216

Re: How to hookup battery pack to a servo?

myka wrote:
Mon Jun 03, 2019 8:54 pm
... I just randomly start soldering wires together lol
Don't do that. It's the fastest way to destroy your Pi.

You need to draw a diagram of the breadboard wiring that works, then transfer that to a stripboard layout (or whatever other system you choose).
by davidcoton
Mon Jun 03, 2019 8:26 pm
Forum: Beginners
Topic: Using capacitor buffer across GPIO pins
Replies: 15
Views: 2069

Re: Using capacitor buffer across GPIO pins

Alarms which deliver maximum security should never rely on short-to-earth for detecting closed or open-circuit and would have to do false-trigger detection in software. But, in other situations, that's acceptable, and one might as well leverage a capacitor's usefulness for hardware debouncing and f...
by davidcoton
Mon Jun 03, 2019 8:15 pm
Forum: General discussion
Topic: Audio input raspberry pi 3
Replies: 4
Views: 138

Re: Audio input raspberry pi 3

Is there a way to do that without buying a 8channel usb audio interface? Possibly, though I've not tried. The PI GPIO has an i2s interface that might be an alternative to USB. I don't know if it can handle 8 channels, and I don't know the pros and cons. It won't get you out of buying some form of a...
by davidcoton
Mon Jun 03, 2019 8:45 am
Forum: Beginners
Topic: Using capacitor buffer across GPIO pins
Replies: 15
Views: 2069

Re: Using capacitor buffer across GPIO pins

The delay we're talking about is less than one second :) IIRC the specification for UK approved alarms requires action in response to and alarm input in between 300ms and 700ms. (I worked on very early microprocessor based alarm systems around 1981 -- memory may be faulty and standards may have cha...

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