Easy outdoor PiAware station


#1

Guys:

I’ve just finished building an inexpensive, exterior-capable PiAware station using PVC pipe and related materials as the housing. A dump of pictures I took during the construction process is at the following link, I’ll post an “instructable” somewhere as soon as I can:

goo.gl/photos/3fRJh2qzJu7Rd6wY9

The main differences from an ordinary PiAware Pro 2 station are:

  • PVC pipe for the enclosure, which is cheap and easy to work with
  • NanoPi2 Fire rather than a Raspberry Pi, because it’s about half the size
  • Power-over-ethernet power supply, which saves me at least one cable

Information regarding the NanoPi is here: wiki.friendlyarm.com/wiki/index. … oPi_2_Fire

b.g.


#2

Nice setup mate.

Pretty slick how it’s all together and minimalistic. Well done.

I really like the NanoPi2-Fire, but the U.S. distributor is out of stock and they charge as much shipping as the unit costs almost if ordering from China, so will be a wait and see thing I guess.

Can do me a solid sometime if you are bored? I’d like to see how that CPU stacks up - Can install sysbench and run a real quick test and paste the results?



sysbench --num-threads=3 --test=cpu --cpu-max-prime=5000 --validate run


For reference, Pi3 runs that in roughly ~25-27 seconds
Any particular headaches with software setup as it pertains to the RTL or Piaware, or is it a relatively straight forward Debian install?

EDIT: Can the admin(s) PLEASE relax the ModSecurity crs regex a little? It’s borderline ridiculous as it stands. No disrespect to this place, but there is security and then there is overboard.


#3

Can you mail me a timestamp when you see a false positive? Then we have a point in the logs to look at. The problem is that there is a massive pile of correctly blocked attacks and a small handful of false positives and it’s hard to find the false positives without a specific time to look at.


#4


bgat@flightaware0:~$ sysbench --num-threads=3 --test=cpu --cpu-max-prime=5000 --validate run
sysbench 0.4.12:  multi-threaded system evaluation benchmark

Running the test with following options:
Number of threads: 3
Additional request validation enabled.


Doing CPU performance benchmark

Threads started!
Done.

Maximum prime number checked in CPU test: 5000


Test execution summary:
    total time:                          21.4394s
    total number of events:              10000
    total time taken by event execution: 64.3066
    per-request statistics:
         min:                                  6.11ms
         avg:                                  6.43ms
         max:                                 11.68ms
         approx.  95 percentile:              10.76ms

Threads fairness:
    events (avg/stddev):           3333.3333/1.25
    execution time (avg/stddev):   21.4355/0.00




#5

I’m using the filesystem that FriendlyARM refers buyers to, which looks to me to be a pretty plain-vanilla Debian Jessie setup. Doing a dist-upgrade seems to break it, though, and I’m suspicious it’s due to a recent change in console names since I just got bitten by that on another, unrelated project. (I do embedded Linux for a living.)

I chose the NanoPi2 Fire because of its combination of size, CPU, and peripheral mix—in particular, the lack of onboard WiFi. I didn’t want any more interference sources inside the can than absolutely necessary, and I had ethernet there anyway.

The usual minor hiccups regarding mechanicals occurred.

I didn’t apply any conformal coating, so I don’t expect the whole setup to survive more than a year or so before condensation-triggered corrosion sets in. I’ll pull it apart in the spring and spray it down, hopefully that’ll be soon enough. I didn’t want to risk ruining the connectors before I knew that the setup would work the way I wanted it to.


#6

Thank you for running that quick test. It’s showing maybe 15-20% increase over the Pi3, but can take single tests with a grain of salt. Either way, it does illustrate somewhat higher performance. And yes I opted for only three threads since didn’t want to disrupt anything else that may have been running in the background or to be too obtrusive to see what ballpark it landed in.

I too like the absence of Wifi for these applications for the same reasons. Even though I disable wifi and bt at the kernel level when using Pi3 for this type of thing, it would be a bonus not to deal with if it’s not needed. I too like the size and Gbit capability…even though I doubt the bus could completely swallow a saturated Gbit line…even so it should be a bonus depending on intended use.

Hopefully the U.S. distributor gets more in stock as I refuse to pay $15 or more to ship a $22 device of this size. Would be a fun little board to tinker with.

Thanks again for sharing your setup - I enjoy seeing things that are outside the box so to speak.


#7

Thanks for sharing this (especially the photos!). I think I will do something similar myself, rather than spend too much time trying to source a ready-made IPX-whatever electronics enclosure.

I just got my PiAware feeder set up indoors last week using a handy Pi Zero W and the general-purpose dipole antenna that came with my RTL-SDR dongle (suction-cupped to the inside of the glass patio door on our 4th floor balcony). I decided to upgrade to the blue Flightaware dongle straight away, to get a 1090 mhz filter + amp but also to have the original dongle back to play with for other projects.

My aim now is to move to an improved, outdoor antenna on the balcony. I have power outside, so the primary concern is a convenient weatherproof enclosure. I think I will likely use a 512mb Orange Pi Zero (primarily for size reasons), but we shall see.

Being on the 4th floor of a 16-storey building, I’m not the highest point around by any stretch but I’m still wondering what steps I should take to deal with static accumulation and/or lightning… have others gone to significant lengths for safety`s sake?


#8

Lightning path is through the least resistance. It is why lightning rods work so well.

Tall buildings have a lightning rod on top. No need for extra lightning protection on a balcony.

Glass is an insulator and lightning can’t travel through glass. I guess it could shatter if hit but lightning wouldn’t go there with lots of other lower resistant targets around.

Most “lightning damage” on PiAware is from the power line. Use a power strip surge protectors and you should be fine.


#9

Lightning Protection -Single Point

Lightning_Protection_-_Single

Lightning Protection -Multiple Point

Lightning_Protection_-_Multiple_R


#10

Thanks, David.

My building is brand new (in fact, still partially under construction) so I expect - but do not know for sure - that it has appropriate lightning protection. I don’t take anything for granted, but for the time being I’ll assume all is well in that department.

I’m not really concerned about lightning while my antenna is indoors behind the glass patio door. But, that said, I was most concerned about static build-up in these types of systems, especially since I think most people using Raspberry Pi for this probably don’t have a fantastic ground. For example, my current antenna feeds into the RTL-SDR dongle via a length coax cable, and then into a Pi Zero W in a minimal acrylic case (just enough to prevent shorts when placing it on metal surfaces), which is fed 5V via a USB power cord connected to a 2-prong power adaptor…

Does anyone here actually use a metal enclosure, or have a Pi case with a decent, grounded power supply? Or have you grounded your system in another way to deal with static?


#11

Enhanced Protection against Lightning

The NEC/CEC allow for increased protection in high-lightning areas by the optional installation of the following:

  1. A Building lightning protection system (LPS) consisting of lightning rod(s), down conductor(s), and earth rod(s)
  2. Surge protectors on the AC power wiring;
  3. Additional surge protectors on signal wiring (internet, phone, cable);
  4. “Supplementary protection” (also called “Point-of-Use” protection) at the equipment to be protected.

#12

There is a small protection diode on the prostick antenna input. This clamping diode can bleed off any static voltage on the input. It will not protect against larger voltages. Most of the cheaper RTL dongles also have the input protection diode.

Most of the problems I have seen are due to the power supply or surges through the power supply. Power supply surges are much more common and very cheap to prevent. Search for “surge protector”.

Metal enclosure offer little benefit.

Or have you grounded your system in another way to deal with static?

The 5V micro USB wall plug usually has protection built in. If you read the manual for the power supply it will usually list a few types of protection. I would just add a surge protector + power supply to prevent extremely high voltages.


#13

The second building is how our Hanger’s lightning protection is installed. I say to the least, the building takes a strike every lightning storm


#14

On a related note I’ve found that I can get minor skin burns from the FlightAware external antenna metal bracket. The antenna, preamp, Pro Stick Plus and RPi are all indoors on a windowsill. The antenna is mounted, via its bracket, on a small wooden rod on the window sill.

The RPi PSU is the official one and this is a switched mode supply with a floating ground which produces the familiar tingling effect when touching the metal case or connectors, caused by microamp earth coupling. The presence of the preamp or not makes no difference.

The metal bracket on the antenna is connected to the same via the coax’s braid, but something about the antenna construction appears to cause a high voltage at the bracket such that in the dark, if I brush it with a metal object, tiny sparks are visible. If I brush the bracket with a finger, I feel that familiar tingle but any slight cut on the skin gets a burning sensation, presumably caused by the high voltage at microamps. Doing the same at the RPi end of the coax and the tingle is there but never any sparks or that burning sensation.

Anyone else experience this? Also, if this is ever mounted outdoors then I presume the possibility of corrosion due to the presence of this voltage and atmospherics acting as an electroyte becomes a reality.


#15

The RPi PSU is the official one and this is a switched mode supply with a floating ground which produces the familiar tingling effect when touching the metal case or connectors, caused by microamp earth coupling. The presence of the preamp or not makes no difference.

Thanks for sharing, this is basically what I was concerned about. I’m not super satisfied with the lack of ground in such a system and am wondering if I should consider constructing a purpose-built power supply that actually provides a ground to discharge it.