Raspberry Pi Forums

ragnarjensen

viewtopic.php?f=41&t=72015
A stock RPi in a MRI scanner managed about 1T, then the ethernet connector stopped working (there's small ferrite cores in it.)
He substituted ethernet and USB connectors for non-magnetic ones and went over 3T.

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Ragnar

ragnarjensen

Have a look in the /proc/asound/... directory tree. Every audio sub-channel has a "hw_params" file in there. When you "cat" that file, it returns either the word "closed" or the audio format it's currently using. Soundcard 0 is playing: $ cat /proc/asound/card0/pcm0p/sub0/hw_params access: MMAP_INTE...

ragnarjensen

I have a bunch of these LEDs. I use them to give some surveillance cameras night vision. They are 1W, pulling about 350 mA when going full tilt. The potentiometer does not adjust the brightness, it is used to adjust the sensitivity of the light sensor (how dark it should be for the LED to turn on). ...

ragnarjensen

I'm not sure what you actually want to do... but if it's reading RC PWM with the RPI; Using an Arduino, it's silly easy to read the pulses from a RC receiver hooked directly to a digital input. Arduino has a pulseIn() function that returns the pulse width directly, in microseconds. RC_receiver.jpg T...

ragnarjensen

Hi all, First post here! Welcome! 8-) I wanted to know, what is another recommended usb to hdmi displaylink adapter that will work on my pi? I've used a couple of these; https://www.amazon.com/Display-Monitor-Converter-Graphic-Adapter/dp/B008H4JGII They're sold under a lot of different brand names....

ragnarjensen

@lordaker It looks like you didn't get all of the Xorg.0.log file, the last part seems to be missing.

ragnarjensen

EDID is a mechanism that is used by the display adapter and the monitor, where the monitor can tell the display adapter which capabilities it has, e.g. resolutions. For some reason your display adapter is not getting the information it wants from the monitor. Does your VGA cable have all 15 pins? Th...

ragnarjensen

Hi! All is well, thank you. In the messages from dmesg I see a lot of [ 6.177217] EDID block is all zeroes [ 6.177235] udl 1-1.5:1.0: DVI-I-1: EDID invalid. It looks like the DisplayLink adapter doesn't communicate properly with the monitor. I see in you pictures that you are using a VGA cable. Have...

ragnarjensen

The X log file doesn't show anything being wrong... The output from the dmesg command? Also, what happens if you swap the physicals screens, 221E2 on DisplayLink and 220SW on HDMI? PS: I'm saying that all my Pis are headless. Headless is when a computer doesn't have any screen at all, i.e. I'm unabl...

ragnarjensen

What does the X log file say? It's in /var/log/Xorg.0.log on my Raspbian systems.
Also the output from the dmesg command could be interesting.

Note! I don't run USB DisplayLink any longer myself. All my Pis are headless nowadays, so I can't test anything.

ragnarjensen

I have googled a little on your Kensington K33907 DisplayLink adapter.
Apparently it only supports resolutions up to 1440 x 1050.

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Ragnar

ragnarjensen

And if you have a subsection with Modes in there?

Code: Select all

SubSection	"Display"
    		Modes	"1680x1050"
EndSubSection

I have never had to use the Randr extension myself.

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Ragnar

ragnarjensen

The keyword to set screen resolutions is "Modes"
The "Mode" keyword is something very different.

Have you tried without the Subsection Display?

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Ragnar

ragnarjensen

I think the USB Displaylink driver is included in Raspbian nowadays. You shouldn't have to build it yourself.
As far as I know, the driver only supports USB2 devices. There exists an USB3 driver for Ubuntu, but it's partly closed source and only runs on x86.

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Ragnar

ragnarjensen

A single stereo track. Left channel to the speaker in the prop and right channel to the speaker behind the victim.
No need to switch outputs and it would make the overlap easy to do, too.

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Ragnar

ragnarjensen

I have the clear version of that case. On the inside of the lid there are four posts for the camera board.

: Camera board pressed on to posts; canakit_case_camposts.jpg (62.33 KiB) Viewed 719 times

The lens peeks out through one of the holes in the raspberry logo.

: RaspiCam in Canakit case; canakit_case_cam_in_lid.jpg (62.84 KiB) Viewed 719 times

The case has slots on all sides for flat cables.
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Ragnar

ragnarjensen

When Raspbian went from Wheezy to Jessie, things changed. The Pi3 introduced further changes. This might help you getting the serial console going: http://spellfoundry.com/2016/05/29/configuring-gpio-serial-port-raspbian-jessie-including-pi-3/ https://www.abelectronics.co.uk/kb/article/1035/raspberr...

ragnarjensen

The command line program arecord will display a simple VU meter if you use its verbose flag twice or more.

Code: Select all

arecord -vv  ...

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Ragnar

ragnarjensen

Maybe connect a LED to the Tx pin?
viewtopic.php?p=736408#p736408

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Ragnar

ragnarjensen

Haemogoblin wrote:Fantastic will those commands work straight off from booting up in to console?

They can be made to start automatically at boot, yes.
I have added the needed start scripts to the repository, in the folder initscripts.

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Ragnar

ragnarjensen

I've written some small programs that might help you.
https://github.com/RagnarJensen/PiLEDlights

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Ragnar

ragnarjensen

rern wrote:@ragnarjensen
After hours of seacrhing for GPIO LED for USB drive, your code is the only one I've found that do exactly I want. Please advice how to make it works on ArchLinux.

I'm sorry, but I have never used ArchLinux.
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Ragnar

ragnarjensen

Code: Select all

[email protected]:~$ uptime
 22:59:20 up 688 days, 43 min,  2 users,  load average: 0.09, 0.06, 0.02

Model B Rev 2 that is DNS and DHCP server, DynDNS updater and monitors an UPS.
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Ragnar

ragnarjensen

It does 192 kHz/24 bit on all in- and outputs. I have used it at that rate to record and play back the multiplexed signal in FM stereo transmissions; audio that goes up to 75 kHz. I know of others that record the ultra-sound of bats with it.
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Ragnar

ragnarjensen

RSSI has no stated values. It does not correspond to any particular physical property. The WiFi dongles I use (zd1211-based) present values between 0 and 100. I think Atheros-based dongles go from 0 to 127 and Apple devices from -100 to 0. The manufacturers can choose any range they want.

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Ragnar

Search found 330 matches

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