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by obcd
Tue Feb 17, 2015 1:27 pm
Forum: Troubleshooting
Topic: 3G modem stability
Replies: 2
Views: 1902

Re: 3G modem stability

Have you tried to power the modem stick directly without that transistor. What transistor are you using? If the 3G needs between 500mA and 1A, I doubt the Pi can deliver enough base current to fully drive the transistor. This might result in voltage drops which might trigger the usb instabilities. Y...
by obcd
Wed Feb 11, 2015 11:07 am
Forum: Troubleshooting
Topic: RPI2 power issues?
Replies: 12
Views: 2533

Re: RPI2 power issues?

Could it be RF interference from the stick into the Pi electronics? I had some issues with a Huawei 3G stick. When I put a cable between the stick and the Pi, the problems went away. Maybe your Y cable is doing the same and making the distance from the stick to the Pi larger decreasing possible inte...
by obcd
Fri Jan 17, 2014 12:54 pm
Forum: Troubleshooting
Topic: rPi GPIO to Mosfet - won't fire relay coil
Replies: 10
Views: 4592

Re: rPi GPIO to Mosfet - won't fire relay coil

You could connect the led with a decent serie resistor on the 24V relais voltage as well. Due to the high voltage drop over those resistors, they will heat up a little. Assume you want 8mA passing trough your led. R = 24 - 1.2 / 0.008 = 2850 Ohm P = I * I * R = 0.008 * 0.008 * 2850 = 0.18W So basica...
by obcd
Thu Jan 16, 2014 3:06 pm
Forum: Troubleshooting
Topic: Showing error
Replies: 5
Views: 671

Re: Showing error

You might start by giving a little more information.
Real time videos?
Do you mean video from the Pi camera?
Ethernet optical link?
The Pi ethernet connector is only 100Mbit, so why an optical link?
by obcd
Thu Jan 16, 2014 2:58 pm
Forum: Troubleshooting
Topic: rPi GPIO to Mosfet - won't fire relay coil
Replies: 10
Views: 4592

Re: rPi GPIO to Mosfet - won't fire relay coil

Have a look at npn darlington transistors like TIP120 instead of mosfets. You will need a resistor (1K)between your gpio output and the base of the darlington transistor. A darlington only needs 1.4 - 1.5V to conduct. It's current driven while mosfet gates are voltage driven. Due to the fact it's a ...
by obcd
Tue Jan 07, 2014 9:28 am
Forum: Troubleshooting
Topic: Connecting to internet via cable and router
Replies: 7
Views: 1138

Re: Connecting to internet via cable and router

Try to connect an ethernet switch to the wall socket and connect the Pi to that switch. If the problem is 2 much attenuation of the ethernet signals, that should fix the issue. I once serviced some bad wiring connection. An old pc with 10Mbit adapter could connect fine. A newer one with a 100Mbit ad...
by obcd
Mon Jan 06, 2014 1:51 pm
Forum: Troubleshooting
Topic: Connecting to internet via cable and router
Replies: 7
Views: 1138

Re: Connecting to internet via cable and router

It could still be the cable and the wall socket. Most network adapter have an option to swith to 10Mbit speed if 100Mbit isn't working. At 10Mbit, only 2 pair = 4 wire of the 8 are used. For 100Mbit, you need all 4 pair if I remember well. I have no idea if the Pi would work when only 2 pair of the ...
by obcd
Tue Dec 24, 2013 3:45 pm
Forum: Troubleshooting
Topic: Edimax Wi-Fi adapter not functioning correctly
Replies: 27
Views: 3545

Re: Edimax Wi-Fi adapter not functioning correctly

If you have both ethernet and wifi connected to the same subnet, isn't it using the wired connection for it's communication? In such case, it might get it's dhcp for the wifi adapter trough the cable.
by obcd
Tue Dec 24, 2013 3:15 pm
Forum: Troubleshooting
Topic: Car stereo - Raspbmc question
Replies: 9
Views: 1684

Re: Car stereo - Raspbmc question

The terminology isn't raspberry pi related. It's the DLNA way of defining the system components. I am not an apple user myself, but I am sure some will be able to answer your question. A DLNA approach would use your iphone as server only and the Pi as controller and rederer. Be aware that the analog...
by obcd
Tue Dec 24, 2013 3:01 pm
Forum: Troubleshooting
Topic: Why running from USB better than from sd card?
Replies: 31
Views: 11067

Re: Why running from USB better than from sd card?

It's not nonsense. I use some Pi's to connect usb devices to a virtual windows computer on a linux kvm system. It works fine with a read only rootfs. There are plenty of other things where a read only rootfs can work. For those using the system, it's just an interface. I can't expect them to ssh in ...
by obcd
Tue Dec 24, 2013 1:52 pm
Forum: Troubleshooting
Topic: Why running from USB better than from sd card?
Replies: 31
Views: 11067

Re: Why running from USB better than from sd card?

Plus any shuffling it does is controlled atomically If that's the case, than why is Swissbit selling special sd cards for embedded systems with the guarantee that either the old data or the new data will be read back from the card after an interrupted write. They just are unpayable expensive. Isn't...
by obcd
Tue Dec 24, 2013 1:16 pm
Forum: Troubleshooting
Topic: Car stereo - Raspbmc question
Replies: 9
Views: 1684

Re: Car stereo - Raspbmc question

however I want to remove using the phone from the solution all together It's rather confusing. You want to play the music on your phone and remove the phone from the solution? DLNA works with a server - controller - renderer setup. The 3 unit's can be on different hardware. So basically, your Pi wi...
by obcd
Wed Dec 11, 2013 6:01 pm
Forum: Troubleshooting
Topic: Internet traffic
Replies: 3
Views: 619

Re: Internet traffic

Yes, that should be it. So obvious... Thanks.
by obcd
Wed Dec 11, 2013 5:06 pm
Forum: Troubleshooting
Topic: Restart instead of halt
Replies: 7
Views: 1303

Re: Restart instead of halt

I had such issues as well.
You need the latest firmware for a Pi with 512MB of ram.
You need a recent kernel with that firmware as well or it will reboot instead of halt.

I ended up recompiling my kernel to fix those issues. (It had some config settings changed.)
by obcd
Wed Dec 11, 2013 4:59 pm
Forum: Troubleshooting
Topic: Marine Hub - Web Cam Problem
Replies: 12
Views: 2362

Re: Marine Hub - Web Cam Problem

Are you connecting to the external ip adress? Are you sure your internet provider allows you to have a server listening on port 8081? Some internet providers block ranges of ports, as a user connection is optimised for downloading traffic and not uploading traffic. You could also have another firewa...
by obcd
Wed Dec 11, 2013 4:35 pm
Forum: Troubleshooting
Topic: Internet traffic
Replies: 3
Views: 619

Internet traffic

I use a pi to connect an usb swiper to a virtual windows machine. It's using usbip and it's root fs is based upon debian. It's kernel is based upon the 3.6.11+ with usbip added. Due to the recompilation, it's revision reverted to #1 It's rootfs is normally mounted read only, and the swap file was di...
by obcd
Sat Dec 07, 2013 1:27 pm
Forum: Troubleshooting
Topic: Made in UK and China - power problems
Replies: 6
Views: 1256

Re: Made in UK and China - power problems

The original poster basically says that the Pi won't boot when powered from the 1 Amp Samsung usb socket.
Using a power adapter, it worked.
Unless besides the supply, he changed the OS image as well, how could the OS image be his problem?
by obcd
Wed Dec 04, 2013 3:49 pm
Forum: Troubleshooting
Topic: Modem using USB serial I/O
Replies: 18
Views: 4071

Re: Modem using USB serial I/O

RING sounds like the normal string a hayes compatible modem is sending on an incoming call. I would expect the modem to need some init commands or some handshake line set before it will send the caller id information when a call comes in. Using the Y cable might make you wiser. You could connect the...
by obcd
Wed Dec 04, 2013 3:16 pm
Forum: Troubleshooting
Topic: Made in UK and China - power problems
Replies: 6
Views: 1256

Re: Made in UK and China - power problems

Maybe the china one is a 256MB and the RS UK one is a 512MB type?
The 512MB type uses a different memory chip. Maybe it uses more current due to that?
Have you measured the TP1 - TP2 voltage on the working and non working unit?
by obcd
Sat Nov 23, 2013 2:32 pm
Forum: Troubleshooting
Topic: My Pi destroys USB sticks
Replies: 7
Views: 1947

Re: My Pi destroys USB sticks

The power to the usb pors passes trough the Polyfuse. Usb memory sticks can be very power hungry and probably your setup trips the polyfuse. So, are the usb memory sticks connected directly to your PI? You have 2 of them connected? I sometimes bridge the polyfuse with another additional 1 Amp polyfu...
by obcd
Sat Nov 23, 2013 12:33 pm
Forum: Troubleshooting
Topic: I think I killed it...
Replies: 2
Views: 833

Re: I think I killed it...

It sure sounds dead. It's not up to us to judge if you killed it. Something on the board is consuming 2 much current. For that reason, if you power it using the micro usb socket, the polyfuse trips. If you power it over the gpio, the polyfuse can't trip, but the system is still indicating excessive ...
by obcd
Tue Nov 19, 2013 10:09 am
Forum: Troubleshooting
Topic: SD Card Corruption
Replies: 10
Views: 1844

Re: SD Card Corruption

One way to prevent sd card corruption is creating a read only rootfs. This basically means you should disable swap and create a tempfs in ram for the log files and other stuff that needs write access. Maybe changing the behavour of this 2 things, even without a read only rootfs might already help a ...
by obcd
Tue Nov 19, 2013 9:56 am
Forum: Troubleshooting
Topic: SD Card Corruption
Replies: 10
Views: 1844

Re: SD Card Corruption

The subject has indeed been brought up several times. The scary part about it is the fact that nobody seems to know what is causing the sd card corruption. It might be interesting to see if you can fix the sd cards by reformatting them with the special sd card formatting tool. A sd card can get dama...
by obcd
Mon Nov 18, 2013 7:19 am
Forum: Troubleshooting
Topic: Shortcircuiting...
Replies: 17
Views: 1881

Re: Shortcircuiting...

The red wire should never be connected to the led directly. You probably blew your second led as well by connecting it to GND and 3V3 directly. The red wire should be connected to the resistor, and the other end of that resistor should be connected to the positive side of the led. A led always needs...
by obcd
Mon Nov 11, 2013 5:22 pm
Forum: Troubleshooting
Topic: Raspberry dies after a day or so
Replies: 13
Views: 1959

Re: Raspberry dies after a day or so

Not really a solution, but you could enable the watchdog. You could even ping an adress at regular intervals, and have it trigger the watchdog if it can't reach it's destination. This would at least save you the trip to power cycle it when things go wrong. You can create some loggings yourself when ...

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