RPi 3 A+ running V4.1.0 RC7

General support for the Pi-Star System
VK5BB
Posts: 8
Joined: Mon Sep 10, 2018 4:31 am

Re: RPi 3 A+ running V4.1.0 RC7

Post by VK5BB » Fri Feb 14, 2020 6:38 am

Hi,

Further to my last post, it is all in the lead!!!

I have changed the lead I have been normally using to a shorter heavier?? lead and.............no throttling back and no low voltage issues. Currently running off my main home computer, an older HP, and there does not seem to be any issues.

I consistently get the following reports;

[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$

Also, the unit is running cooler sitting between 48 d C to 50 d C then slowly toggling between the two even when the hot spot is active in a QSO.

The unit has been running for a couple of hours, had a number of longish QSO's and all seems to work neatly.

Ran a load test on one cut USB lead and at 5.01 volts @ 600 mA it dropped 2 volts, so it is all in the lead!

More tests to run, including on these USB battery power bank units, it seems they do sag under load.

Thanks again, I will add more information when I more to report.

73, Ben VK5BB

KE7FNS
Posts: 948
Joined: Wed Apr 17, 2019 11:11 pm

Re: RPi 3 A+ running V4.1.0 RC7

Post by KE7FNS » Fri Feb 14, 2020 9:32 pm

VK5BB wrote:
Fri Feb 14, 2020 3:53 am
Many thanks for the feed back, very much appreciated. It really is a bit of a learning curve playing at this level, however with the right prompting, I can "follow the bouncing ball"!
No problem, glad I could help figure out what was going on. I've had a bit of a run in with under voltage and a dodgy cheap power supply once before, but it only seems to trigger at the start of the boot process, and then doesn't trigger anymore, although I haven't really stressed it out 100% to see. I guess I should test it one of these days.
VK5BB wrote:
Fri Feb 14, 2020 3:53 am
OK, re the power supply, I am aware of power supply issues with the RPi's but did not think of it here as I generally run them of my computer USB port or a portable 5 volt USB battery pack. I think the old adage here is; "Never assume?" Even the computer USB may be low?
Laptops generally have 2 different power output levels on different USB ports. I know HP labels one as a "charging port" with a little lightning bolt icon that delivers more power (1500 mA), the standard USB 2 ports are limited to only 500 mA and USB 3.0 are limited to 900 mA which isn't enough for a RPi 3 or 4 variant.

I think your issue is a combination of lower mA at the port, a dodgy USB cable, and CPU load.

Maybe you can just pick up a wall wart, they generally output 5.25 volts to negate some voltage loss in the USB cable, although that won't make up for the one that cable that drops 2 volts. That cable needs to get filed in the recycle bin.

If it must be portable, then I'd quit using laptop USB ports or power banks for power, and pick up some 2 cell (7.4 v) or 3 cell (11.1v) lipo battery packs commonly used in RC planes or cars, and pick up a variable voltage regulator and cobble up something that can deliver more power. Then you are going to need some way to charge the lipo pack.
VK5BB wrote:
Fri Feb 14, 2020 3:53 am
However I will investigate this further. At this time I fitted a USB voltage and current dongle into the power circuit and it is showing around the 4.8 volts at 290mA. I am also not sure of the losses through these dongles so will have to check that out too.

Just ran : dmesg | grep -i volt

Serious under voltage issues..........

[email protected](ro):~$ dmesg | grep -i volt
[ 6.233442] Under-voltage detected! (0x00050005)
[ 45.752004] Voltage normalised (0x00000000)
[ 70.712025] Under-voltage detected! (0x00050005)
[ 74.872016] Voltage normalised (0x00000000)
[ 85.272022] Under-voltage detected! (0x00050005)
[ 122.712019] Voltage normalised (0x00000000)
[email protected](ro):~$

The above was when the unit is running off a fully charged 10,000mAh battery pack. Need to check the leads too? It is not as if 300 - 400 mA is that much to cause voltage drop but then with cheap leads you can never be sure? The USB voltage/current monitoring dongle is showing a bit of jitter on both voltage corresponding with current changes.

OK, running: top

top - 13:51:45 up 5 min, 2 users, load average: 0.00, 0.07, 0.04
Tasks: 116 total, 1 running, 115 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.4 us, 0.5 sy, 0.0 ni, 99.1 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 477.9 total, 278.4 free, 107.0 used, 92.6 buff/cache
MiB Swap: 0.0 total, 0.0 free, 0.0 used. 305.2 avail Mem

The only thing running on this RPi 3A+ is Pi-Star V4.1.0 RC7 and is only configured for D-Star operation.

My next step is to put it on my service bench in the shack and run it off the bench supply and see what happens?

73, Ben VK5BB
I think that data is invalid because your device was not actually throttled, the last message was that it was normalized, so it would of only reported that an under voltage had happened since boot but it was not currently experiencing the issue.

There might be some background service that is kicking off that is causing the load to increase which is causing the under voltage problem, you might need to wait for that situation to happen and then gather the data.
VK5BB wrote:
Fri Feb 14, 2020 6:38 am
Hi,

Further to my last post, it is all in the lead!!!

I have changed the lead I have been normally using to a shorter heavier?? lead and.............no throttling back and no low voltage issues. Currently running off my main home computer, an older HP, and there does not seem to be any issues.

I consistently get the following reports;

[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$ sudo vcgencmd get_throttled
throttled=0x0
[email protected](ro):~$

Also, the unit is running cooler sitting between 48 d C to 50 d C then slowly toggling between the two even when the hot spot is active in a QSO.

The unit has been running for a couple of hours, had a number of longish QSO's and all seems to work neatly.

Ran a load test on one cut USB lead and at 5.01 volts @ 600 mA it dropped 2 volts, so it is all in the lead!

More tests to run, including on these USB battery power bank units, it seems they do sag under load.

Thanks again, I will add more information when I more to report.

73, Ben VK5BB
Well that is good news.

Good luck and have fun.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

VK5BB
Posts: 8
Joined: Mon Sep 10, 2018 4:31 am

Re: RPi 3 A+ running V4.1.0 RC7

Post by VK5BB » Mon Feb 17, 2020 7:01 am

Hi,

Thank you to all who have responded and provided advice and guidance.

Just a followup with some of my recent findings.

I have set up a USB lead breakout connector which is connected to my electronic variable power supply dummy load, I can vary the current drawn at the input voltage and watch both current and voltage at the terminals. Separately I can monitor the source voltage at the USB A connector to see what the power supply does under load.

In testing several 5 volt USB style battery packs,
My cheap 8000mAh unit sags from 5.01 volts to 4.88 volts at 500mA.
A friends 26,600mAh unit sags from 5.22 volts to 4.98 volts at 500mA.

The lead that I used is a heavier style lead, 300mm long, USB A to USB micro.
Connected to a small buck regulator, from 13.8v to 5.1 volts, when under load, at 1000mA it drops at the micro USB end, from 5.1v to 4.98 volts. So at 1 amp, the lead drops 120 millivolts. Part of this may be in the micro USB connectors??

Further to my RPi 3A+ Pi-Star hot spots, I have confirmed that when run off a bench supply at 5.1 volts, not sagging, the hot spot runs cooler and does not throttle back, 46 -48 d C.

My new iteration RPi 3A+ unit has an on board UPS hat (DF Robot) with a single 2000mAh 3.7v LiPo cell. I am lead to believe that this UPS hat can support up 2.6 amps peak at 5 volts. This unit has been running for several hours and it too is running relatively cool at 46 d C.

So, as pointed out by many, if the RPi has a stable 5 volt supply, it appears that they do run nicely without my previously experienced throttling and running hot.

So, thank you to the folks that provide me with feedback and assistance, it has been much appreciated.

I may be found monitoring or logged into our local D-Star repeater, VK5RWN C.

Enjoy your hot spots.

Regards and 73, Ben VK5BB

User avatar
w7efs
Posts: 333
Joined: Sun Apr 22, 2018 4:26 pm

Re: RPi 3 A+ running V4.1.0 RC7

Post by w7efs » Tue Feb 18, 2020 2:42 am

Not sure why "sudo" was suggested for the vcgencmd invocation, but it's not at all necessary.

KE7FNS
Posts: 948
Joined: Wed Apr 17, 2019 11:11 pm

Re: RPi 3 A+ running V4.1.0 RC7

Post by KE7FNS » Tue Feb 18, 2020 6:40 am

w7efs wrote:
Tue Feb 18, 2020 2:42 am
Not sure why "sudo" was suggested for the vcgencmd invocation, but it's not at all necessary.
:lol:
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

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