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by rpdom
Sat Nov 18, 2017 6:17 pm
Forum: General discussion
Topic: Secure delete/erase SD using encryption
Replies: 11
Views: 307

Re: Secure delete/erase SD using encryption

It has been suggested to overwrite many times. This may or may not eventually hit all those hidden blocks. It won't. Some blocks will have been marked as end of life and will never be used again. It is possible that they still contain the original data. Bottom line is that if the data on there is i...
by rpdom
Sat Nov 18, 2017 5:45 am
Forum: General discussion
Topic: Secure delete/erase SD using encryption
Replies: 11
Views: 307

Re: Secure delete/erase SD using encryption

Using multiple erase passes on an SD card is pointless and can help wear out the card. A single pass is all that is required. The theory with hard disks is that some residual magnetism could be left on the disk after zeroing a block and with the right equipment it is sometimes possible to recover so...
by rpdom
Fri Nov 17, 2017 6:11 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Does DSI have better support
Replies: 10
Views: 252

Re: Does DSI have better support

That would depend on the resolution and how clever the driver is.
(I've no idea, to be honest).
by rpdom
Fri Nov 17, 2017 6:09 am
Forum: General discussion
Topic: Raspberry Pi for commercial use
Replies: 23
Views: 8357

Re: Raspberry Pi for commercial use

Why is the pi zero a dead end ? For a start the restricted supply (one item per person per day at most retailers). Unless you want really large quantities, in which case contact RPT and negotiate a price (it will probably be higher per unit than the retail cost of the single items). Then the fact t...
by rpdom
Fri Nov 17, 2017 5:07 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Does DSI have better support
Replies: 10
Views: 252

Re: Does DSI have better support

That depends on the screen. Most of the small screens that connect to GPIOs use the SPI bus. There are various drivers for those. None of them use the GPU. They often copy the framebuffer to the screen. Some larger screens can use the DPI interface which uses almost all of the GPIOs to give an 18-bi...
by rpdom
Fri Nov 17, 2017 4:58 am
Forum: General discussion
Topic: Auto running a program after boot
Replies: 17
Views: 10207

Re: Auto running a program after boot

If you've got wiringpi installed (it usually is), you could add the following into your bash script # Check to see if pins 39 and 40 are jumpered # Set Pin 40 to input with pull-up (BCM 21) gpio -g mode 21 up # If there is a jumper this GPIO will read low, otherwise it will read high jumper="$(gpio ...
by rpdom
Thu Nov 16, 2017 6:41 pm
Forum: Beginners
Topic: Open CV operates better in Ubuntu Mate or Raspbian??
Replies: 1
Views: 62

Re: Open CV operates better in Ubuntu Mate or Raspbian??

They should be both pretty much the same, but I'd go for Raspbian as it has better support here.
by rpdom
Thu Nov 16, 2017 6:30 pm
Forum: Compute Module
Topic: Making a IO board
Replies: 9
Views: 245

Re: Making a IO board

My understanding ins that using a SD card has a slower read and write time that an eMMC. Is that true? Maybe, but I wasn't suggesting using the SD card for anything other than a one time setting of the boot flag. After that the card will never be needed again. The CM3L will then be able to boot dir...
by rpdom
Thu Nov 16, 2017 6:43 am
Forum: Compute Module
Topic: Making a IO board
Replies: 9
Views: 245

Re: Making a IO board

If you want extra storage you can use the USB, the same as on a Pi 3B. Perhaps get the CM3L and initially put in in a carrier board with an SD card that sets the USB boot OTP bit. Then have USB storage on your own board with whatever capacity you require.
by rpdom
Thu Nov 16, 2017 6:32 am
Forum: General discussion
Topic: 4k Videos in raspberry pi3
Replies: 3
Views: 154

Re: 4k Videos in raspberry pi3

No, not video. Some people have managed to get a 4K desktop running slowly. The hardware acceleration in the chip is designed to handle up to HD (1080p h264) video, so 4K video would have to be processed in software and that means pushing huge amounts of data around at speeds that the Pi 3B can't re...
by rpdom
Wed Nov 15, 2017 7:45 pm
Forum: Beginners
Topic: Getting 12V or 24V inputs - best practice
Replies: 3
Views: 116

Re: Getting 12V or 24V inputs - best practice

All Pi models only take 3.3V inputs. To interface those to higher voltage levels you will need some sort of converter. The simplest is a resistor voltage divider to bring the level down, but for full isolation (best practice in industrial fields) you'd use an opto-isolator (or opto-coupler) with a s...
by rpdom
Wed Nov 15, 2017 8:46 am
Forum: Troubleshooting
Topic: Which GPIOs won't boot HIGH on a PI 3?
Replies: 2
Views: 92

Re: Which GPIOs won't boot HIGH on a PI 3?

Which pins are you using? As that states, GPIOs 2 and 3 (pins 3 and 5) have strong pull-up resistors on the board. It'd be best to avoid using those if you need a pull-down. Any other of the standard GPIOs can be used. A 10K pull-down resistor should make sure they stay low unless driven high. Oh, w...
by rpdom
Tue Nov 14, 2017 7:51 pm
Forum: Troubleshooting
Topic: MPEG2 license not working
Replies: 5
Views: 174

Re: MPEG2 license not working

fnordje wrote:
Tue Nov 14, 2017 5:08 pm
Will it work in Docker as well now?
I don't know. I've only briefly looked at running Docker on a Pi so far. I spend a lot more time running it on x86_64 based systems.
by rpdom
Tue Nov 14, 2017 6:44 am
Forum: Troubleshooting
Topic: MPEG2 license not working
Replies: 5
Views: 174

Re: MPEG2 license not working

How is your GPU/CPU memory spilt set? The codec will not be available if the GPU memory is set below about 64MB (IIRC).

Code: Select all

vcgencmd get_mem gpu
by rpdom
Sun Nov 12, 2017 2:12 pm
Forum: Beginners
Topic: Resistors - which should I use?
Replies: 6
Views: 166

Re: Resistors - which should I use?

I most cases you should be fine with the 220 Ohm resistor. The LED will be a little brighter, but still well within limits for the LED and the GPIO pin.

It does depend on the circuit though. Could you link to the particular one, or a link to the magazine issue.
by rpdom
Sun Nov 12, 2017 12:32 pm
Forum: Beginners
Topic: PWM on pi3
Replies: 7
Views: 241

Re: PWM on pi3

If I understand correctly, on pi3 there are only 3 pwm pins, BCM 18 and 12, (both marked as pwm0) and pin 13 (marked as pwm1) is this correct? Yes, those are the pins that can use the hardware PWM controller. BCM12 and 18 both use the same PWM channel, so can't be set to different rates. Most of th...
by rpdom
Sun Nov 12, 2017 11:22 am
Forum: Raspbian
Topic: Possible scripting for raspi-config?
Replies: 6
Views: 312

Re: Possible scripting for raspi-config?

Use sudo raspi-config to enable/disable "predictable" names.
by rpdom
Sun Nov 12, 2017 11:06 am
Forum: Troubleshooting
Topic: GPIO pins revert on Stretch
Replies: 5
Views: 176

Re: GPIO pins revert on Stretch

Could you just confirm which physical pin numbers the LED is connected to on the board.
by rpdom
Sun Nov 12, 2017 10:21 am
Forum: General discussion
Topic: When "http://mirrordirector.raspbian.org/" server running again?
Replies: 5
Views: 278

Re: When "http://mirrordirector.raspbian.org/" server running again?

The ipv6 addresses seem to have been a bit of a crimson fish. apt tried the ipv4 address first, then tried ipv6 before giving up. The message with the ipv6 address overwrote the ipv4 address line.
by rpdom
Sat Nov 11, 2017 8:51 am
Forum: General discussion
Topic: Remote reset
Replies: 16
Views: 434

Re: Remote reset

Thanks guys. I have an iLO capability on my HP server which means I can do a "bare metal" install remotely. I just wondered if there was something that the ingenious Pi community had to do the similar thing. I guess I was looking for the remote version of holding down the "shift" key when rebooting...
by rpdom
Sat Nov 11, 2017 8:02 am
Forum: General discussion
Topic: Remote reset
Replies: 16
Views: 434

Re: Remote reset

Of course, I'm sure my post wouldn't help the thread-opener at all. But in general such a scenario is possible! True, and I would have mentioned it if it wasn't somewhat risky and the OP said "from a Remote Desktop", to which the answer is really "no, you will need ssh at some point and some custom...
by rpdom
Sat Nov 11, 2017 7:57 am
Forum: Troubleshooting
Topic: “apt-get update” fails
Replies: 10
Views: 531

Re: “apt-get update” fails

The repo is probably just down. The repo is mirrored on many sites, most of which are probably fine. It looks like the server that automatically routes your request to a local mirror is inaccessible so it can't route you. Hard coding one of the mirrors from the list of raspbian mirrors in /etc/apt/...
by rpdom
Sat Nov 11, 2017 7:49 am
Forum: Troubleshooting
Topic: “apt-get update” fails
Replies: 10
Views: 531

Re: “apt-get update” fails

It's not the foundation servers (archive.raspberrypi.org), it's the Raspbian mirror director servers (or at least one of them). Perhaps Mythic Beasts are having problems? I haven't found any reports yet, but I can't get to raspbian.org at all.
by rpdom
Sat Nov 11, 2017 7:14 am
Forum: Troubleshooting
Topic: “apt-get update” fails
Replies: 10
Views: 531

Re: “apt-get update” fails

Fails on my system too since yesterday afternoon, but with different message. Proposed workaround does not help. This happens even with a fresh image! I tried many times yesterday evening and this morning and always get the same error. I've just tried running apt-get update and it is failing to con...
by rpdom
Sat Nov 11, 2017 5:35 am
Forum: General discussion
Topic: Remote reset
Replies: 16
Views: 434

Re: Remote reset

That is pretty much impossible. You'd need to overwrite the SD card that the Pi is running from, and as files are in use on that card the Pi would almost certainly crash.

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