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by Burngate
Mon Mar 25, 2019 6:49 pm
Forum: HATs and other add-ons
Topic: Interfacing with another system running 5 volts
Replies: 3
Views: 53

Re: Interfacing with another system running 5 volts

A resistor only drops voltage when current passes through it - Ohm's law. Since GPIOs are very high impedance, they won't pass any current, so you need something else to take that current, and a second resistor to ground is ideal. Just make sure their values - or rather the ratios of their values - ...
by Burngate
Mon Mar 25, 2019 6:33 pm
Forum: General discussion
Topic: Is this micro sd card good?
Replies: 33
Views: 704

Re: Is this micro sd card good?

Heater wrote:
Sun Mar 24, 2019 4:50 am
... a grocery store .... As in a shop that sells vegetables.
A grocer just sells household goods, archaically in large quantities (gross)
A shop that sells just veg should be called a greengrocer - even though spuds shouldn't be green
by Burngate
Mon Mar 25, 2019 6:25 pm
Forum: Beginners
Topic: Breadboard not powering
Replies: 9
Views: 147

Re: Breadboard not powering

The breadboard in the photos doesn't seem to be "gotcha'd" in that way - the red and blue lines are continuous. What might help the OP would be to take the back off the breadboard (if it's got screws holding it together). He could then see what connects to what, and possibly draw lines on the top wi...
by Burngate
Fri Mar 22, 2019 11:49 am
Forum: Beginners
Topic: Sinusoidallly Modulated Signal Output
Replies: 4
Views: 103

Re: Sinusoidallly Modulated Signal Output

Headphone jacks and plugs ("jack" refers to the female connector) are just a way to keep things tidy. A pair of wire cutters and a soldering iron will allow you to create an adapter between your two pins and a 3.5mm TRRS plug that you can then plug directly into the Pi 3B+ - no need for any extra so...
by Burngate
Thu Mar 21, 2019 10:36 am
Forum: General discussion
Topic: Pi 3B male 40 pin header - gold, nickel or tin plating?
Replies: 15
Views: 660

Re: Pi 3B male 40 pin header - gold, nickel or tin plating?

Many years ago, my employer sent me on a soldering course at Cranfield, where it was suggested that gold flashing was a really bad idea, and we should wash off the gold using copious amounts of solder. It seems to me you have several choices. Do nothing and live with the consequences. Do as you sugg...
by Burngate
Wed Mar 20, 2019 7:07 pm
Forum: Beginners
Topic: Hall effect sensor with electricity cables
Replies: 5
Views: 165

Re: Hall effect sensor with electricity cables

... I can detect if the is a magnet nearby. When I tried it with a cable with power running through, it doesn't detect it. Be aware that the field around a wire carrying a current is tiny compared to the field round a permanent magnet, unless the current is massive It ain't the power, which is Volt...
by Burngate
Tue Mar 19, 2019 10:25 am
Forum: Troubleshooting
Topic: Replace Broken Component (capacitor, transistor, resistor?)
Replies: 10
Views: 232

Re: Replace Broken capacitor - [Solved]

upandcominggamer wrote:
Tue Mar 19, 2019 4:15 am
I'm not sure how these forums work, but feel free to close the topic moderators! ;)
Best option appears to be for you to edit your first post, and change the subject to something like
"Replace Broken capacitor - [Solved]"
by Burngate
Mon Mar 18, 2019 7:22 pm
Forum: Beginners
Topic: Breadboards and Phat
Replies: 10
Views: 171

Re: Breadboards and Phat

The term you're looking for to put into Google is "Cobbler", for no apparent reason that I can see. Also Google doesn't like it, either, until I put in "AdaFruit" who among others make them - you attach it to the Pi with a ribbon cable and plug it into the breadboard.
by Burngate
Mon Mar 18, 2019 7:11 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Original SD Card wiring 3 B+
Replies: 3
Views: 99

Re: Original SD Card wiring 3 B+

It's a great shame we cannot now see as much as we could of the original Pi. That had everything visible! Still, there are the CM and CMIO documents, including the SD card slot, so you might be able to trace things round - SD cards all have the same wiring, including the micro ones and the holders t...
by Burngate
Sun Mar 17, 2019 12:10 pm
Forum: Beginners
Topic: Input Relays
Replies: 21
Views: 409

Re: Input Relays

Is there a reason behind that?
I can't see what difference it would make, given the relative sizes of the voltages involved.
by Burngate
Sun Mar 17, 2019 12:01 pm
Forum: Networking and servers
Topic: Hidden information about manufacturer.
Replies: 9
Views: 364

Re: Hidden information about manufacturer.

As an aside, it slightly bemuses me that the manufacturer is given as "Raspberry Pi Foundation"
Surely the Foundation does nothing of the sort - it leaves it to Raspberry Pi Trading, who licence (?) Farnel and RS, who get Sony to build it.
by Burngate
Sun Mar 17, 2019 11:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: HDMI interference re-setting my Pi?
Replies: 2
Views: 101

Re: HDMI interference re-setting my Pi?

A couple of things spring to mind. If the only connection to earth is via the monitor, and removing that connection removes the problem, then I would suspect the monitor. "... and inadvertently nudged a power supply to the security cameras. That re-set the Pi3B." I'm not sure what a nudge is, but ev...
by Burngate
Sat Mar 16, 2019 12:22 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RPI 3 A+ USB Peripheral Mode Power
Replies: 2
Views: 106

Re: RPI 3 A+ USB Peripheral Mode Power

It's generally not a good idea to have two power supplies fighting each other.
by Burngate
Sat Mar 16, 2019 12:18 pm
Forum: Off topic discussion
Topic: Worried, Whatever-Speed
Replies: 57
Views: 1331

Re: Worried, Whatever-Speed

Just out of interest, I got a couple of 16x32 LED panels.
The LEDs are either on or off, so to create a grey-scale image, I had to create a "PWM"-style output, and re-write it continuously.

Basic / Python made it flicker, but assembler was quick enough to be nice and smooth.
by Burngate
Sat Mar 16, 2019 12:12 pm
Forum: Beginners
Topic: Input Relays
Replies: 21
Views: 409

Re: Input Relays

Why not use a light sensor?
by Burngate
Fri Mar 15, 2019 7:15 pm
Forum: Other projects
Topic: Power for outoor enclosure
Replies: 4
Views: 212

Re: Power for outoor enclosure

Although mains is less dangerous on your side of the Atlantic than on ours, I'd still be advising getting a proper electrician to help. Yes, I've removed the cable from a power strip to install it as you want, and reattached it afterwards (actually, removed and replaced the plug from the other end),...
by Burngate
Fri Mar 15, 2019 6:58 pm
Forum: Python
Topic: Use two led panels with one raspberry
Replies: 1
Views: 109

Re: Use two led panels with one raspberry

I'm no Python expert, and haven't done this with anything on Raspbian, so you may want to ignore me ... It took me some time to get one of these panels working using RiscOS, but adding a second was quite straightforward. All I had to do was change it from (16 deep by 32 wide) to (16 deep by 64 wide)...
by Burngate
Wed Mar 13, 2019 11:43 am
Forum: Camera board
Topic: Pi NoIR Camera v2 [IR settings]
Replies: 7
Views: 222

Re: Pi NoIR Camera v2 [IR settings]

If it's an official RPi camera, there's no connection for IR LEDs, so it won't work.
If it's a Chinese clone with those connections, it's unlikely to be able to supply enough current to light the LEDs, and can damage your Pi.
by Burngate
Wed Mar 13, 2019 11:39 am
Forum: Beginners
Topic: Electric pulse scanner
Replies: 8
Views: 275

Re: Electric pulse scanner

A Hall-effect sensor merely senses magnetic fields, in this case produced by electric current. What size current is required to produce an output will depend on the particular sensor, how close it is to the wire, whether there's any magnetic material involved, such as ferrite, whether the wire is wr...
by Burngate
Tue Mar 12, 2019 6:25 pm
Forum: Troubleshooting
Topic: "lightning bolt" low power always on
Replies: 6
Views: 134

Re: "lightning bolt" low power always on

Also note: if your OS isn't up-to-date, the under-voltage indication could be erroneous.
by Burngate
Mon Mar 11, 2019 6:50 pm
Forum: General discussion
Topic: Stroboscope Guitar Tuner With RPi-Controlled LEDs
Replies: 7
Views: 315

Re: Stroboscope Guitar Tuner With RPi-Controlled LEDs

While I was writing wot I rote, I had in the back of my mind both of those options, and it took just over an hour for someone to find the holes in my argument. ;) It rather depends on what you consider easy or complex, in terms of either software or hardware. I would consider using the Pi's hardware...
by Burngate
Mon Mar 11, 2019 12:08 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO Pin specs, Why is there no documentation on Broadcom site?
Replies: 10
Views: 379

Re: GPIO Pin specs, Why is there no documentation on Broadcom site?

Does "The Raspberry Pi 3V3 supply was designed with a maximum current of ~3mA per GPIO pin. If you load each pin with 16mA the total current is 272mA. The 3V3 supply will collapse under that level of load." still apply to all Pi's as the later ones had a bigger 3.3v supply? Does the 50mA max still ...
by Burngate
Mon Mar 11, 2019 12:00 pm
Forum: General discussion
Topic: Stroboscope Guitar Tuner With RPi-Controlled LEDs
Replies: 7
Views: 315

Re: Stroboscope Guitar Tuner With RPi-Controlled LEDs

I would think the Pi is the wrong tool for the job. Yes, a Pi could illuminate a LED for the required short time, but No, it couldn't do so at precisely the right rate, and certainly not using the standard Raspbian (Linux) operating system. That's because it's not only running your program - it's al...
by Burngate
Sun Mar 10, 2019 10:34 am
Forum: Troubleshooting
Topic: Pi 2 B - solid red and green lights only boots with breadboard attached
Replies: 6
Views: 168

Re: Pi 2 B - solid red and green lights only boots with breadboard attached

With nothing connected to the GPIO header, it won't boot. With ribbon (I assume) to cobbler onto breadboard with "a couple sensors installed on it and an MCP-3008" it boots. It seems to me it's either a real hardware problem, or it's software. To eliminate software, put a freshly downloaded copy of ...
by Burngate
Sat Mar 09, 2019 6:38 pm
Forum: Python
Topic: How could I adjust this code to open a 12 volt linear actuator before opening the garage door?
Replies: 29
Views: 742

Re: How could I adjust this code to open a 12 volt linear actuator before opening the garage door?

Hm.
From now on, I'm going to keep a local copy of every thread I reply to, just in case.
Or maybe starting tomorrow. Or next week.

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