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by obcd
Sun Nov 10, 2013 1:15 pm
Forum: Troubleshooting
Topic: Raspberry pi is wonderful but...
Replies: 19
Views: 6465

Re: Raspberry pi is wonderful but...

Another option you could try is creating a read only rootfs linux setup. You will need to disable swap for that, and you will lose the option to use the sd card for storage. If it's true what is said that corruption is caused by the sd card itself doing background tasks, it shouldn't happen with a r...
by obcd
Thu Oct 24, 2013 11:29 am
Forum: Troubleshooting
Topic: how can do a Raspberry to trigger a 12VDC relay?
Replies: 15
Views: 4295

Re: how can do a Raspberry to trigger a 12VDC relay?

Is that relay one that turns the lights on when you push a button and turns them off again upon the second push of that same button? If that's the case, the Pi will not know if the lights are on or off, but maybe that's not a problem. Farnell 2218566 PiFace might be usefull for your purpose. (I assu...
by obcd
Tue Oct 22, 2013 2:35 pm
Forum: Troubleshooting
Topic: PicoBorg + 7.2v battery
Replies: 5
Views: 1131

Re: PicoBorg + 7.2v battery

The Pi shouldn't need more than 0.7Amps. That's below the specified 1Amp and is fine. The current that will come out the battery depends upon the load connected to it. So, it's not because a battery can deliver 5 Amps, that the load will get 5 Amps. The current specified on a battery is the maximum ...
by obcd
Tue Oct 22, 2013 10:36 am
Forum: Troubleshooting
Topic: how can do a Raspberry to trigger a 12VDC relay?
Replies: 15
Views: 4295

Re: how can do a Raspberry to trigger a 12VDC relay?

All you need is a transistor and a couple of resistors to drive the 12V relay from the 3V3 raspberry gpio's. An optocoupler is only needed if the ground potentials of the relay and that of the Pi are different. It could also be usefull if you want the relay powered when the gpio pin is pulled to gro...
by obcd
Tue Oct 22, 2013 9:14 am
Forum: Troubleshooting
Topic: About microUSB polyfuse of Model B.
Replies: 20
Views: 13834

Re: About microUSB polyfuse of Model B.

SMTP's that can convert both lower and higher voltages to a fixed voltage are called "buck boost" converters.... They are not complex anymore, but they aren't cheap either. Check the ltc3115-1 reference design. A polyfuse with a 2 Amp hold current would be a cheap solution. It would have a lower res...
by obcd
Tue Oct 22, 2013 8:50 am
Forum: Troubleshooting
Topic: Corrupted SD card
Replies: 4
Views: 1569

Re: Corrupted SD card

I would try with another sd card 2 see if the problem goes away with that. If that's ok, you could google for the linux fsck command. The partition you are checking with that should not be mounted. So, you will have to do it on another linux system. You could use a live cd setup for that. Another op...
by obcd
Tue Oct 22, 2013 8:41 am
Forum: Troubleshooting
Topic: Pi does not power off
Replies: 15
Views: 2012

Re: Pi does not power off

I experienced the same behavour when I updated the firmware (boot folder) of my sd card and used it with an old kernel. When I changed the kernel.img as well 2 the most recent from the downloads, the problem went away. I read somewhere that information is stored in one of the watchdog registers to i...
by obcd
Sat Oct 19, 2013 1:59 pm
Forum: Troubleshooting
Topic: Can pi be power from any USB socket?
Replies: 5
Views: 882

Re: Can pi be power from any USB socket?

From a technical point of view, it's not ok to power the Pi from an usb host. The usb specification says that a host port should be able to provide 0.5Amp for it's bus powered clients. The Pi (at least the model B) consumes more than this 500mA. Most devices with usb host ports are able to provide m...
by obcd
Tue Oct 08, 2013 3:12 pm
Forum: Troubleshooting
Topic: Poweroff not working
Replies: 0
Views: 301

Poweroff not working

Neither "sudo poweroff" "sudo shutdown -h now "sudo halt" works as expected. The Pi directly reboots. It's an older 3.2.27 kernel with a read only root fs. As I recently ordered some 512MB pi's, I used the boot folder from a recent raspbian image and replaced the kernel.bin with my old kernel. The i...
by obcd
Tue Jul 09, 2013 4:52 pm
Forum: Troubleshooting
Topic: What to do about USB ports that keep crashing
Replies: 13
Views: 2095

Re: What to do about USB ports that keep crashing

The current rating marked on a polyfuse is his hold current. (It's like that on the datasheets I checked) So the 1A1 6V fuse should be able to pass 1.1 Amp without tripping. Even if it would be true that it trips at 750mA, 300 - 350mA is still very much for a keyboard and mouse. The situation change...
by obcd
Tue Jul 09, 2013 10:45 am
Forum: Troubleshooting
Topic: What to do about USB ports that keep crashing
Replies: 13
Views: 2095

Re: What to do about USB ports that keep crashing

They are a little different, but it's all described in the usb specification. A device should tell the host how much power it needs. If it's connected to a bus powered downstream usb hub, it will be rejected if it uses more than 100mA. The calculations are based upon a 4 port hub. They consider ever...
by obcd
Wed Jul 03, 2013 12:00 pm
Forum: Troubleshooting
Topic: What to do about USB ports that keep crashing
Replies: 13
Views: 2095

Re: What to do about USB ports that keep crashing

Unless the keyboard is a "christmas tree lighted" type of keyboard, I doubt together with the mouse it will consume more than 200mA. besides that, the 100mA limit was only there on the first batch of Pi's that had the usb polyfuses. Those were removed, so the only polyfuse still present is the 1.2 A...
by obcd
Thu May 30, 2013 1:06 pm
Forum: Troubleshooting
Topic: [SOLVED] Low memory.
Replies: 8
Views: 3584

Re: Low memory.

He posted his config file with the gpu_mem=16 line in it....
Why would he all of sudden need to change to 32 if 16 isn't working?
by obcd
Thu May 30, 2013 1:01 pm
Forum: Troubleshooting
Topic: F3 Poly Fuse casuing my problems?
Replies: 6
Views: 6387

Re: F3 Poly Fuse casuing my problems?

@rpdom Even under normal working conditions, the used polyfuse has a voltage drop of 0.15 - 0.2V. This makes the TP1 - TP2 testvoltage close to the under limit considered safe for a stable operation. We all know that silicium breaks faster than fuses, so basically all the polyfuse does is protect th...
by obcd
Thu May 30, 2013 8:06 am
Forum: Troubleshooting
Topic: F3 Poly Fuse casuing my problems?
Replies: 6
Views: 6387

Re: F3 Poly Fuse casuing my problems?

Solder another fuse over the one already there.
It's more difficult to remove a component than to install one.
Have you checked the power consumption of your Pi?
Maybe it needs to much current causing the Polyfuse to trip?
by obcd
Thu May 30, 2013 8:02 am
Forum: Troubleshooting
Topic: Humming sound ( active speakers )
Replies: 8
Views: 3417

Re: Humming sound ( active speakers )

Maybe it's just the fact that the Pi gnd is connected to mains earth trough your tv set when you connect the hdmi cable. You could try a wire between the outer of the RCA video connector and earth to see if that fixes the noise as well. It can come from your Pi supply. Sometimes even reversing the p...
by obcd
Sun May 26, 2013 12:02 pm
Forum: Troubleshooting
Topic: XBOX DVD Remote with Raspbmc
Replies: 2
Views: 1466

Re: XBOX DVD Remote with Raspbmc

The first one might work. The second one is used to connect an usb device to an original xbox1, so it basically is the opposite of what you need. The xbox one controller ports were simply usb ports using a different type of connector. If the xbox one dvd dongle works, it should work with such a cabl...
by obcd
Tue May 21, 2013 2:12 pm
Forum: Nederlands
Topic: Geluid heel zacht (mute?)
Replies: 2
Views: 1140

Re: Geluid heel zacht (mute?)

Als je de sd kaarten van de pi's verwisselt, verplaatst het probleem zich dan?
Anders, een image nemen van de werkende sd kaart en deze plaatsen op de foutieve sd kaart.
by obcd
Tue May 21, 2013 9:38 am
Forum: Troubleshooting
Topic: UART stops on erad
Replies: 1
Views: 501

Re: UART stops on erad

Have you tried to feed it 255 characters?
Maybe it's the non blocking not working as expected?
I assume you disabled the port as debugging serial port and as console terminal port?
by obcd
Tue May 21, 2013 9:32 am
Forum: Troubleshooting
Topic: touch screen
Replies: 2
Views: 625

Re: touch screen

script format is readable text. Have you tried to take a look in the sh scripts to figure out what they are doing? If they load a binary kernel module (driver) you will need one for the Pi arm architecture. A x86 binary driver won't work on the Pi. Maybe if you have the sources you can try to recomp...
by obcd
Sat May 18, 2013 6:22 am
Forum: Troubleshooting
Topic: Fried Pi - Component testing power issues
Replies: 2
Views: 1369

Re: Fried Pi - Component testing power issues

Most Pi setups aren't connected to earth. This means that the GND of the Pi can carry a voltage relative to earth. If you connect one of the gpio pins with your hand, you can connect it to earth like that. Due to that you can introduce voltages on the Pi that can fry the SOC gpio pins. As a result, ...
by obcd
Thu May 16, 2013 7:13 am
Forum: Troubleshooting
Topic: Red LED on Faint Green LED
Replies: 253
Views: 63618

Re: Red LED on Faint Green LED

dd bs=4M if ~/2013-02-09-Wheezy-raspbian.img of=/dev/mmcblk0p1 You are copiing a disk image to a partition. dd bs=4M if ~/2013-02-09-Wheezy-raspbian.img of=/dev/mmcblk0 should be the correct procedure. If you are having a different boot setup like with berryboot, things might be different. The imag...
by obcd
Wed May 15, 2013 8:32 am
Forum: Troubleshooting
Topic: raspberry pi usb not work
Replies: 2
Views: 464

Re: raspberry pi usb not work

Both usb ports are connected to an usb hub chip.
If one of the ports isn't working, I would visually inspect the usb connector.
There are known cases of one of the connector pins being loose and bend over, resulting in a non functional usb port.
by obcd
Wed May 15, 2013 8:27 am
Forum: Troubleshooting
Topic: R31 resistor popped off the PCB
Replies: 7
Views: 1561

Re: R31 resistor popped off the PCB

The TXD and RXD lines are gpio lines. They simply run to the Broadcom SOC which is a micro bga chip. There isn't much you can do hardware wise. You could measure the TXD voltage. It should be approx. 3V or higher. If you dump a file to that serial port, you should see it lowering 0.1 - 0.5V as an in...
by obcd
Tue May 14, 2013 9:20 am
Forum: Troubleshooting
Topic: Having trouble with sleeping the USB drive
Replies: 10
Views: 3656

Re: Having trouble with sleeping the USB drive

Basically, the automatic spindown is a feature in the harddisk itself. Some manufactures provide a separate configuration tool that can be used to enable or disable that feature, and normally, once set, the harddisk should remember that setting. I have no idea if this setting can be changed on the f...

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