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by Burngate
Sun Aug 20, 2017 9:37 am
Forum: General discussion
Topic: WDLabs
Replies: 1
Views: 78

Re: WDLabs

The forum search works for this, surprisingly!
search.php?keywords=PiDrive
by Burngate
Sun Aug 20, 2017 9:30 am
Forum: General discussion
Topic: How to tell if a TTL device is connected
Replies: 3
Views: 91

Re: How to tell if a TTL device is connected

Had a bit of a Google, came up with these: https://www.adafruit.com/product/597 https://learn.adafruit.com/mini-thermal-receipt-printer/microcontroller A bit of education regarding "TTL": https://www.sparkfun.com/tutorials/215 So: send some data to it. If you don't get an ack, there's nothing connec...
by Burngate
Fri Aug 18, 2017 6:02 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3 Keep Crashing after polyfuse reset
Replies: 3
Views: 143

Re: Raspberry Pi 3 Keep Crashing after polyfuse reset

First off, PP1 and PP2 are right at the input; if they're reading about 2.6v then your power supply isn't able to supply the current being asked for and is suffering. By short-circuiting D5, you're shorting across the power input. So short-circuiting D5 is the wrong thing to do - rather, try removin...
by Burngate
Fri Aug 18, 2017 5:47 pm
Forum: Beginners
Topic: pin numbering: wiringPi website vs. others?
Replies: 8
Views: 259

Re: pin numbering: wiringPi website vs. others?

I guess my head works differently from everyone else's. When I've got the soldering iron going, and that lovely smell of flux, I work naturally with pin numbers. Maybe that's the left hemisphere going. But with the keyboard out, BCM numbers make more sense. Is that the right hemisphere at work? And ...
by Burngate
Thu Aug 17, 2017 10:06 am
Forum: Beginners
Topic: Will Pi keep time after removing internet connection?
Replies: 10
Views: 338

Re: Will Pi keep time after removing internet connection?

... 1 or 2 minutes either way after a couple of months is fine ... You're asking for ±1 in 50000 accuracy, or 20 ppm. That appears to be about what one might expect from a crystal oscillator. AFAIK there's only one time-keeping device on-board - a crystal - and it's not been cut specifically for ti...
by Burngate
Tue Aug 15, 2017 3:25 pm
Forum: Troubleshooting
Topic: Camera not working
Replies: 2
Views: 86

Re: Camera not working

... as well as, of course, the little Sunny connector on the board (which may not be labeled "Sunny")
by Burngate
Mon Aug 14, 2017 4:51 pm
Forum: Advanced users
Topic: Pi Zero-W placement for ideal wifi antenna reception (stupid jokes)
Replies: 7
Views: 159

Re: Pi Zero-W placement for ideal wifi antenna reception

... much the same as there isn't a pot of gold at the end of the rainbow. Yes there is. Ask the Unicorns. The problem is getting to the end of the rainbow to find it. :D One fine day many years ago ... actually it was a bit misty, but the sun was shining brightly. We were sitting eating lunch on a ...
by Burngate
Mon Aug 14, 2017 4:50 pm
Forum: Advanced users
Topic: Pi Zero-W placement for ideal wifi antenna reception
Replies: 7
Views: 391

Re: Pi Zero-W placement for ideal wifi antenna reception

WiFi at 2.54GHz has a wavelength of about five inches, so an antenna shorter than about 2½" (half a wavelength), as on Pi zero W, is going to be fairly omnidirectional. But anything conductive within a wavelength or so, or a foot or two, is going to affect the radiation pattern, and could even act a...
by Burngate
Mon Aug 14, 2017 4:32 pm
Forum: Troubleshooting
Topic: Really bad composite video out on Pi 3?
Replies: 27
Views: 841

Re: Really bad composite video out on Pi 3?

That TV has a comb filter in its NTSC decoder. If there is a menu option to turn it off, give it a try. (A comb filter could give the colour fringeing effects if the horizontal frequency of the video signal is not quite bang on the NTSC spec.) And ensure the Digital Noise Reduction is also turned o...
by Burngate
Sat Aug 12, 2017 10:32 am
Forum: Troubleshooting
Topic: I think a component fell out
Replies: 3
Views: 138

Re: I think a component fell out

It looks like it's possibly a filter of some sort. Since your Pi is already partly broken, I'd be inclined to wire across the two end pads, just to see what happens. If it results in WiFi starting to work again, you're quids in. Just be prepared to remove that wire when local officialdom / men in bl...
by Burngate
Fri Aug 11, 2017 5:48 pm
Forum: General discussion
Topic: RPi not booting after power out
Replies: 24
Views: 422

Re: RPi not booting after power out

At any random time, a Pi running off an SD card could be writing to the card, or the card itself could be doing housekeeping. If the power is cut during either of those, the card can become corrupted. Only after a full shut-down is the card not being written to, or doing housekeeping. But, at random...
by Burngate
Thu Aug 10, 2017 5:35 pm
Forum: Troubleshooting
Topic: Random MAC address/0 cpu serial number
Replies: 9
Views: 1420

Re: Random MAC address/0 cpu serial number

DougieLawson wrote:
Thu Aug 10, 2017 2:16 pm
pmatija wrote:
Fri Jan 30, 2015 1:49 pm
......:
It's a bug in u-boot, you need to go and ask the developers about it...
I doubt he'll bother, since he hasn't logged in for 2½ years ...
by Burngate
Thu Aug 10, 2017 10:29 am
Forum: Python
Topic: Using a shift registe
Replies: 3
Views: 168

Re: Using a shift registe

That looks correct. Regarding edge triggering, I can do no better than pointing to https://electronics.stackexchange.com/questions/21886/what-does-edge-triggered-and-level-triggered-mean Edge Triggering: In edge triggering the circuit becomes active at negative or positive edge of the clock signal. ...
by Burngate
Wed Aug 09, 2017 6:11 pm
Forum: General discussion
Topic: pi zero rip off HDMI port
Replies: 2
Views: 189

Re: pi zero rip off HDMI port

The HDMI port is just a connector, so the Pi will work happily without it. However, by the sound of it, you were less careful than necessary when removing it from your Pi3. Other things shouldn't come off with it! So I would recommend practicing soldering on something less valuable before "ripping" ...
by Burngate
Wed Aug 09, 2017 6:05 pm
Forum: Python
Topic: Using a shift registe
Replies: 3
Views: 168

Re: Using a shift registe

Shift registers come in many flavours, sipo (serial in parallel out) & piso (parallel in serial out) being the most common. If you want to use a 74HC595, have a look at its data sheet https://www.onsemi.com/pub/Collateral/MC74HC595-D.PDF 74x595 is serial in, so it needs some method of entering the d...
by Burngate
Wed Aug 09, 2017 5:21 pm
Forum: Automation, sensing and robotics
Topic: Powering Robot with 9V Batteries
Replies: 8
Views: 348

Re: Powering Robot with 9V Batteries

Since a bare L298N chip cannot provide 5v, I assume you are referring to a board with a L298N and a regulator on it. So your Pi is very much at the mercy of what that regulator can provide. By your description, that regulator can only just supply enough for your Pi without WiFi. Perhaps you could pr...
by Burngate
Tue Aug 08, 2017 4:56 pm
Forum: Off topic discussion
Topic: Linux advocacy department...
Replies: 18
Views: 997

Re: Linux advocacy department...

I think we've seen 20 years or so of brain washing where Microsoft and Apple have been getting computers into schools. It's good that the Pi came along as an alternative. The school my daughter went to from age 5 to 11 (so '93 to '09) was thinking of getting into computing. One of the other parents...
by Burngate
Tue Aug 08, 2017 4:31 pm
Forum: Off topic discussion
Topic: Linux advocacy department...
Replies: 18
Views: 997

Re: Linux advocacy department...

It's not productive bashing things, It used to be the only way to "fix" an old TV ... Surprisingly, it quite often worked, particularly with valve EHT circuits. Hit the right bit of the cabinet, and the cathodes of the PL509 etc. would lose some crud off their surface. If there was still some oxide...
by Burngate
Mon Aug 07, 2017 4:29 pm
Forum: General discussion
Topic: Account deletion?
Replies: 61
Views: 2254

Re: Account deletion?

Comes from the penchant of soldiers to not want to do as they're told. The barrack-room is where they sat discussing what they were going to do about it, and the barrack-room lawyer was the one guy who didn't get into trouble when they didn't obey orders because he told them they didn't have to. Hav...
by Burngate
Mon Aug 07, 2017 4:19 pm
Forum: Automation, sensing and robotics
Topic: Creating a 0-10V voltage range for ballasts
Replies: 38
Views: 9497

Re: Creating a 0-10V voltage range for ballasts

How to determine power supply for OP-AMP circuit ? Should it be twice the input voltage range ? You want the op-amp to give an output between 0v and 5v. Have a look at the Texas Instruments PDF http://www.ti.com/lit/ds/symlink/lm124-n.pdf , particularly the diagram on page one To output 0v, the op-...
by Burngate
Mon Aug 07, 2017 10:49 am
Forum: Troubleshooting
Topic: Magnet - degaussing coil - ruined Pi Zero?
Replies: 7
Views: 383

Re: Magnet - degaussing coil - ruined Pi Zero?

https://en.wikipedia.org/wiki/Cathode_ray_tube Colour display tubes have three separate electron guns, firing beams through a varying magnetic field provided by a focussing coil and deflection coils as well as "convergence" coils., and hoping that enough electrons get through the shadow-mask holes ...
by Burngate
Fri Aug 04, 2017 8:53 am
Forum: Bare metal
Topic: Protection GPIO pins
Replies: 6
Views: 454

Re: Protection GPIO pins

Accidents do happen. At some time in the future, you will set both GPIO's to OUTPUT, and set one High and the other one Low. Or some-one else's software will. Or your kid brother takes a pair of scissors to the interconnecting cable, shorting both GPIOs to ground. The reason I suggested two resistor...
by Burngate
Thu Aug 03, 2017 6:20 pm
Forum: Troubleshooting
Topic: [Solved] USB not working - Raspberry pi 2
Replies: 30
Views: 15536

Re: [Solved] USB not working - Raspberry pi 2

Then I tested the AP2552 IC and found the following: 1. Pin1 - 4.98V 2. Pin3 - 0.02V 3. Pin4 - 0.03V 4. Pin5 - 0.00V 5. Pin6 - 0.00V Okay, so with those measurements, it would seem that both the Enable in and the Fault out are low. (by the way, I believe it's a 2553, not 2552, so the Enable should ...
by Burngate
Thu Aug 03, 2017 5:38 pm
Forum: Bare metal
Topic: Protection GPIO pins
Replies: 6
Views: 454

Re: Protection GPIO pins

It might also be worth putting a resistor in series - or two, one at each end - so that no damage will occur if you accidentally set both as output.
Anything above 200R would work, 1k would be a reasonable value, and keep it below 100k anyway.

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