Go to advanced search

by Burngate
Mon Feb 19, 2018 10:39 am
Forum: General discussion
Topic: Replacing the Pi3 ethernet port?
Replies: 21
Views: 1418

Re: Replacing the Pi3 ethernet port?

What do you consider the hard part?

The details of those magnetics are on page 3 of https://docs-emea.rs-online.com/webdocs ... 6496c8.pdf
If you look on the Pi site for the circuits of the earlier Pis, you'll see how the socket is connected.
EthernetSocket.png
EthernetSocket.png (24.11 KiB) Viewed 394 times
by Burngate
Sat Feb 17, 2018 10:41 am
Forum: Troubleshooting
Topic: Raspberry PI 3 not booting [solved]
Replies: 2
Views: 152

Re: Raspberry PI 3 not booting

Nightwalker83 wrote:
Sat Feb 17, 2018 6:36 am
Edit:

Chip U14 is missing (A9t) off the board.
Well, that would stop it working.
It's part of the Ideal diode on the power input.

One wonders how it came to fall off.
by Burngate
Sat Feb 17, 2018 10:11 am
Forum: Beginners
Topic: Confused about voltages
Replies: 5
Views: 221

Re: Confused about voltages

You're right, the GPIO pins that Pimoroni's blinkt uses (pins 16 & 18, GPIOs 23 & 24) aren't 5v tolerant. To find out all the grubby details, you'll need to find a spec-sheet for APA102 LEDs - otherwise known as DotStar. But I'm fairly certain Pimoroni wouldn't allow 5v anywhere near the GPIOs EDIT:...
by Burngate
Fri Feb 16, 2018 12:00 pm
Forum: Graphics, sound and multimedia
Topic: pi player piano
Replies: 11
Views: 392

Re: pi player piano

>>Are you teaching music or technology? I teach music. The lesson I'm planning will cover Conlon Nancarrow, player pianos, music tech, and black midi. Not helpful, but I find interesting - my maternal grandfather, James Bell Brow, was a Player Piano music arranger. He and his wife Emma Lillian spen...
by Burngate
Thu Feb 15, 2018 7:11 pm
Forum: Beginners
Topic: MCP3008 use for detecting battery capacity
Replies: 6
Views: 220

Re: MCP3008 use for detecting battery capacity

I've no idea! Many years ago, Sony made a professional camera and a battery pack to go with it. The battery was eight nicad cells, 12v nominal, and the camera gave a warning at 11v and shut down at 10.5v. That preserved the battery because no cell could be reverse-charged. You could get about 90% of...
by Burngate
Thu Feb 15, 2018 6:57 pm
Forum: Troubleshooting
Topic: Reviving two PIs by doing nothing for 2 months
Replies: 10
Views: 432

Re: Reviving two PIs by doing nothing for 2 months

Am I being thick?

The Pis are all facing the same way, but the camera boards alternate!
by Burngate
Thu Feb 15, 2018 6:44 pm
Forum: Automation, sensing and robotics
Topic: Controling 6 homemade solenoids
Replies: 5
Views: 271

Re: Controling 6 homemade solenoids

Scotty101 is probably right - relays would be safer. But my take on that is ... a relay board is usually an opto-isolator driving a transistor driving the relay, and a relay is just a solenoid that flicks a switch ... do we really need a solenoid to drive a solenoid? Just so long as: 1) you have a c...
by Burngate
Thu Feb 15, 2018 12:16 pm
Forum: Automation, sensing and robotics
Topic: Controling 6 homemade solenoids
Replies: 5
Views: 271

Re: Controling 6 homemade solenoids

A ULN2003 is eight devices in one chip, so six isn't a problem. You can use it to drive anything - a motor, a solenoid, a LED, a home-made phaser, Harry Potter's wand, anything that needs less than 500mA But that could be the source of problems: if you don't know the characteristics of your solenoid...
by Burngate
Wed Feb 14, 2018 6:14 pm
Forum: General discussion
Topic: "U5" in raspberry pi3 model B
Replies: 3
Views: 268

Re: "U5" in raspberry pi3 model B

U13 is an AP2553, controlling the 5v to the USB ports. It first appeared on the B+ U10 first appeared on the B+, and could be a linear regulator for the analogue audio driver U11 U17 first appeared on the 2B v1.1, together with the separate memory chip on the other side of the board, just beneath U2...
by Burngate
Wed Feb 14, 2018 11:09 am
Forum: Beginners
Topic: MCP3008 use for detecting battery capacity
Replies: 6
Views: 220

Re: MCP3008 use for detecting battery capacity

... to detect the voltage / capacity of an auxiliary battery ... Do be aware that the voltage of a battery isn't directly related to its remaining capacity - the voltage can stay relatively constant until it's almost empty, at which point it takes a nose-dive (and the battery could be destroyed by ...
by Burngate
Mon Feb 12, 2018 7:12 pm
Forum: Beginners
Topic: Distance sensor that penetrates glass
Replies: 25
Views: 764

Re: Distance sensor that penetrates glass

PiGraham wrote:
Mon Feb 12, 2018 6:41 pm
A Class 1 laser is safe under all conditions of normal use.
Ah ... I'd missed that bit - sorry.

Just so long as he sticks to that one or similar. Which he can't, within budget.
by Burngate
Mon Feb 12, 2018 6:54 pm
Forum: Beginners
Topic: unassembled pi3
Replies: 22
Views: 733

Re: unassembled pi3

Since my home has no tablet, iOS or android or other, and my daughter & I sit with our laptops on the dining-room table (together with a Pi or three plus other stuff at my end) I see no reason to hogtie ourselves to WiFi, when we can have the full cat-5 bandwidth.
by Burngate
Mon Feb 12, 2018 6:43 pm
Forum: Raspbian
Topic: Lost HDMI output without apparent reason
Replies: 10
Views: 341

Re: Lost HDMI output without apparent reason

... so it must be a software problem, unless something has failed in the Pi hardware. Have you swapped the SD cards and extras between the Pis? (or equivalently swapped the Pis between the software and add-ons) I'm assuming that "different but similar use" implies there's more than just a Pi involv...
by Burngate
Mon Feb 12, 2018 6:18 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: How to wire a Raspberry Pi to a Sainsmart 5v Relay Board
Replies: 76
Views: 204453

Re: How to wire a Raspberry Pi to a Sainsmart 5v Relay Board

In this situation, BC529 won't work, it's pnp (apparently - no-one seems to have the pdf)
by Burngate
Mon Feb 12, 2018 6:10 pm
Forum: Beginners
Topic: Distance sensor that penetrates glass
Replies: 25
Views: 764

Re: Distance sensor that penetrates glass

If this is for a car on normal roads, and you're thinking about using a laser, it might be worth considering the safety of the driver in front.
I know I would get irritated if the guy behind shone a laser into my rear-view mirror, even from 100m away.
by Burngate
Mon Feb 12, 2018 11:57 am
Forum: Automation, sensing and robotics
Topic: Detect heat of stovetop?
Replies: 9
Views: 257

Re: Detect heat of stovetop?

Is there any small device that could optimally be relatively small, have some sort of networking capability (bluetooth), battery powered, able to be made waterproof (I guess that's just any case really), and also be able to measure how warm it is, whilst being able to withstand the temperature? Bas...
by Burngate
Sun Feb 11, 2018 10:51 am
Forum: General discussion
Topic: New in the Forum.
Replies: 2
Views: 137

Re: New in the Forum.

Under the "General" heading, there's a "sticky: Introduce yourself" viewtopic.php?f=63&t=319
If you add yourself to that, there'll be 3269 posts!

Also, you can add your location to your profile, which may help people answer any queries you have
by Burngate
Sat Feb 10, 2018 6:49 pm
Forum: General discussion
Topic: Raspberry Pi current felt!!!?
Replies: 38
Views: 1450

Re: Raspberry Pi current felt!!!?

Although the power supply is floating - meaning there's no connection between mains input and earth, and output - there will always be some capacitance between the mains circuit and the output. This means that there can be approximately half-mains potential between earth, all-be-it very high impedan...
by Burngate
Sat Feb 10, 2018 6:13 pm
Forum: General discussion
Topic: Dual fan and heatsink problems
Replies: 7
Views: 355

Re: Dual fan and heatsink problems

jameswilles wrote:
Sat Feb 10, 2018 11:29 am
... one of those dual fans and heatsink thingys ...
Have you a link to that?
by Burngate
Thu Feb 08, 2018 12:06 pm
Forum: Teaching and learning resources
Topic: Help with source for KS2 info on radio waves/antennas
Replies: 3
Views: 227

Re: Help with source for KS2 info on radio waves/antennas

When I was at the top end of that age-range (7 - 11,as I understand it) I borrowed M. G. Scroggie's Foundations of Wireless from the local library, and never looked back. The author died in 1989; an 11th edition of his book was published in 1997, revised by SW & RS Amos (who also wrote Principles of...
by Burngate
Wed Feb 07, 2018 7:17 pm
Forum: General discussion
Topic: Safe Use of RESET on Pi Zero
Replies: 7
Views: 339

Re: Safe Use of RESET on Pi Zero

Would it be worthwhile investigating using a read-only file system - put everything into a ramdisc?

Also, no-one has quantified the other part of your query "... after a period of, say, a few hours?"
With the RUN held low, time doesn't pass, so a second or so is identical to an eon.
by Burngate
Wed Feb 07, 2018 6:34 pm
Forum: General discussion
Topic: Pi not booting when changing hats
Replies: 2
Views: 146

Re: Pi not booting when changing hats

Is there a correct way to remove a hat ? Apart from shutting down and removing power, which you did, I don't believe there's any magic involved. should removing hats cause issues ? I can't see how removing either of these two could. I've read somewhere that power issues can be resolved by leaving t...
by Burngate
Tue Feb 06, 2018 12:53 pm
Forum: Automation, sensing and robotics
Topic: What's the lightest, reliable external pull-up I can use?
Replies: 14
Views: 691

Re: What's the lightest, reliable external pull-up I can use?

I'm guessing the 1M pull-up is built-in to the device, and is that high to keep currents small. Why not use the Pi's internal 50k pull-up to 3v3 as well? It will override the 1M (the actual pull-up will be to 3v4 - unlikely to cause a problem) and will draw no extra current from the device's supply....
by Burngate
Tue Feb 06, 2018 10:44 am
Forum: Camera board
Topic: Camera board C8 & C9 capacitors
Replies: 2
Views: 148

Re: Camera board C8 & C9 capacitors

I've not seen a schematic, and haven't done more than a quick prod round with the meter, but ... For both caps, one end - the end nearest the mounting hole - appears to be connected to ground. The other end of each cap seems to be connected to +3v3, which seems odd. Why put two caps in parallel so c...
by Burngate
Sun Feb 04, 2018 4:35 pm
Forum: General discussion
Topic: Raspberry Pi 3B to CRT TV - BLACK Screen
Replies: 12
Views: 865

Re: Raspberry Pi 3B to CRT TV - BLACK Screen

dhawalmewada wrote:
Sun Feb 04, 2018 9:58 am
... then I got a too much unstable and flickering screen. ...
You've got the wrong sort of cable.
Follow davidcoton's advice ... and fruitoftheloom's

Go to advanced search