[OZAPRS] VK2XSE IGate

[Jason Ball]

Pi's are extremely sensitive to voltage problems and bad power supplies.
I've helped a number of people with Pi projects and found it's the most
common cause of problems.   Its even worse if you have wifi drawing power
from the USB port.

A bad power supply will cause problems, without fail.




On Wed, Feb 5, 2014 at 8:52 PM, Ray Wells <vk2tv at exemail.com.au> wrote:

> My first attempts to use the Pi for an aprs gateway were anything but
> successful, with wifi failing anywhere from a few hours to ten days, the
> latter being the longest uptime without a failure. I tried a variety of
> power supply arrangements and looked at supply cleanliness, as well as
> voltage. I then moved away from the Pi.
>
> My return to the Pi was with a DTV dongle for adsb. With one supply, a
> 700mA phone charger, the Pi seemed happy but with other supplies the adsb
> program would crash within seconds. Significant here was the phone supply
> produced 5.22v whilst all others sat just under 5v. I bought a Murata
> 5v/1.5A smps and mounted it inside a commercial 12v/5v cigar socket style
> USB charger thingy. I also shortened the USB lead from about 1m to around
> 300mm.  I shorted all polyfuses. That Pi has just passed 26 days uptime.
>
> Armed with that success I again set up another Pi for aprs gateway
> service. Although it's overkill I used a 3.5A linear supply (LM350) that I
> already had on a heatsink. I set the voltage to 5.1v and that Pi, which
> drives a four port USB/RS232 FTDI adaptor, has now passed 22 days uptime.
> With both Pi's I use Ethernet and get to the wifi LAN via an ethernet/wifi
> bridge.
>
> It seems that voltage for the Pi is even more critical than I initially
> believed. I believe that the voltage at the USB ports, under load, is
> particularly critical to reliable performance.
>
> Ray vk2tv
>
>
>
> On 05/02/14 18:31, Steve wrote:
>
>> I had to go hunting for your bottom post ;-)
>>
>> Here's a uname -r from one of mine. It was last rebooted when I did the
>> apt-get update/upgrade to get it to this state:-
>> Linux sandhills 3.10.25+ #622 PREEMPT Fri Jan 3 18:41:00 GMT 2014 armv6l
>> GNU/Linux
>>
>> To be honest though, most of the problems were sorted by the time your
>> kernel was released so I'm still a bit surprised about your reliability
>> problems.
>>
>> I'm probably not telling you anything you don't already know, but the
>> Raspberry Pi's are very sensitive to power input. If I see 4.7v across TP1
>> and TP2 I start to get worried. If using the Micro USB connector, a good
>> power supply can be crippled by the I2R losses across a poor USB cable.
>> Using that USB port for power puts the Pi on the back foot to begin with I
>> reckon.
>> I feed power in via the GPIO header most of the time.
>>
>> Anyway, good luck!
>>
>> VK2ZSZ
>>
>>
>>
>>
>>  uname -a
>>> Linux car-pi 3.10.1 #2 Tue Aug 20 10:36:16 EST 2013 armv6l GNU/Linux
>>>
>>> running some apt-get commands now if an update will help
>>> (raspbian is the distro)
>>>
>>>
>>>
>>>
>>> -+-+-+-+-+-+-+-+-+-+-+
>>> Liz
>>> VK2XSE
>>> _______________________________________________
>>> OZAPRS mailing list
>>> OZAPRS at aprs.net.au
>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>
>>>
>>>
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>>
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-- 
--
Teach your kids Science, or somebody else will :/

jason at ball.net
vk2vjb at google.com <vk2flnx at google.com>
callsign: vk2vjb
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