Attic Installation Power


#1

After studying a number of great posts here, I decided to try installing my piAware in my attic. There is an AC outlet handy and also a roof vent with some tiny perforations in the side that is easily accessibly. So I placed my inexpensive antenna inside that. Based on this first day of operation I think it is working pretty well. I’m getting consistent reports from planes as far as 200nm away and well distributed around the compass. Some in the 200-250nm range. I’m in the Dallas area and can see planes as far north as Tulsa and Fort Smith and nearly as far south as Austin and Houston. I think that’s great for an $8 antenna.

I am a bit worried though about the power source. The attic temperature never gets that cold (water heaters and central heat is in the attic). But in the summer it can be a seriously unpleasant place to be (Texas). The power adapter I am using does not have any temperature or humidity limitations on the label, though it is overall a high quality adapter.

Am I paranoid to worry about a major failure due to heat/humidity (like a fire)? Is there a USB power adapter that would be spec’d for this (or are all the UL adapters spec’d for this)?

If anyone is curious, I bought one of these antennas. https://www.amazon.com/gp/product/B013S8B234/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1. Once I decide where to leave the piAware give building my own a try.

Thanks ya’ll.


#2

Raspberry pi are not high power devices. Running them will draw 5W of power while doing ADSB. Raspberry Pi have a built in fuse just above 15W. They are designed to stop working if shorted.
I have been running a raspberry pi on the roof for 3 years and haven’t had a problem.

The same goes for the power adapters. They usually have over current protection build in just above their rated power output.
If there was a short most likely the device will break the build in fuse.

Most of the times you hear of people plugging too many devices into an outlet and causing KW of power to short. It just isn’t possible for something that runs 5W with fuses that blow at 15W.


#3

Placing a mag mount antenna over a food can or metallic plate enhances performance.. An additional advantage is that if the can or sheet is made of iron, the magnet in base of antenna clings to it, keeping antenna vertical and prevents it from falling.

I have tried a similar antenna, but it gave me poor results.

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The stock antenna (which came with dvbt dongle), after its whip cut to 52mm, gave me better result than the one with coil.


#4

dbaker - thanks

abcd567- thanks for the comment. I had read about the metal plate trick and plan to try it once I decide the final installation location (probably in the attic). I am fairly satisfied with the reception so far, but it will be fun to experiment with antennas and maybe change places in the attic.


#5

Should you find power adaptors go out in hot weather do some looking around the net for a power over Ethernet setup. They are available that are recommended for Pi installations. Others on this board have used them and they work over an Ethernet cable which would be easy to fish. Several have commented about mounting their Pi in a weather resistant box next to their antenna. I do not know what their local conditions were though.
I have used POE on CCTV cameras and outdoor WiFi routers with good luck. I experienced a constant fail problem with CCTV power supplies in a hot environment and ended up having to move the power supply to a cooler area.
It would not cost anything to research and be ready should you have to go that route. Before going that route study POE supplies because there are several power ratings available.
You are not experiencing anything different from most users here. I bet the vast majority have made trade offs either in feed-line or power.


#6

My first idea was to put a UPS up in the attic and plug the wall wart and the furnace into that.

Lasted a day and my furnace wouldn’t come on. Yep, the UPS couldn’t handle the surge current of the furnace starting up, and popped the circuit breaker. I only have one outlet up there, as the other side of the outlet is hardwired for the alarm system.

Since then I went to a power over Ethernet. I have an old Pi and so I bought a smaller DC adapter. But when I plugged in the SDR to also receive 978, I notice it is at the edge of pulling too much. So I’m going to buy the higher wattage version of the POE adapter. I’ve been using wifi-texas for orders and they ship fast via Amazon.

Other than that, the Power over Ethernet was a great idea. I just put the Pi (with its plastic case) on top of the furnace and figure if it catches on fire, there’s nothing else to burn.

Since we get a lot of lightning here, and I have been hit before with outside antennas (not a direct hit, but close enough to fry my HF radio), I have multiple antennas in the rafters and for 10 years none of them have been hit, or fried the radios from close hits.


#7

My main PiAware setup has been in the attic for quite some time. I had a single light bulb fixture with a pull chain in my attic so I bought a socket plug adapter that has 2 outlets plus another socket and pull chain to get 120VAC for the hardware.

When I upgraded my attic PiAware to a Raspberry Pi 3, I found it runs much warmer than previous versions. My roof is covered with black asphalt shingles and the CPU was getting to the point that it throttled the clock speed because it was so hot (>80C). A little moving air goes a long ways and my current setup controls a 120VAC computer fan that is switched by a Sainsmart relay. I have a program running every 2 minutes that monitors the temperature in /sys/class/thermal/thermal_zone0/temp and turns the fan on around 70C and off around 55C.


#8

When I upgraded my attic PiAware to a Raspberry Pi 3, I found it runs much warmer than previous versions. My roof is covered with black asphalt shingles and the CPU was getting to the point that it throttled the clock speed because it was so hot (>80C). A little moving air goes a long ways and my current setup controls a 120VAC computer fan that is switched by a Sainsmart relay. I have a program running every 2 minutes that monitors the temperature in /sys/class/thermal/thermal_zone0/temp and turns the fan on around 70C and off around 55C.

I had the same issue with my attic install. I ordered a rasp-pi heatsink kit from Amazon for ~$5, and so far it has taken care of the problem.


#9

I ordered a case that included a fan. It worked well.
amazon.com/gp/product/B019S … UTF8&psc=1

The Odroid XU4 I now use came with a fan.


#10

I was thinking about a case like this: https://www.amazon.com/dp/B00M859PA6/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=31F1DM7Z9QL9O&coliid=I3ET4K4KKRQII0.

Is that similar to the case you used?


#11

I added the case link above.
Anything that moves a bit of air will help. The heatsink, without a fan may make things worse. It depends on how well it works and the quality of the heatsink adhesive compound.
I found Piaware complained about high CPU temps more than the OS(ie at a lower temp).


#12

Thanks for adding the link. I’ll probably get one of those.


#13

My original solution was this case from Eleduino:

https://www.amazon.com/gp/product/B012GPCLR6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

The problem was that every time I wanted to add or remove GPIO sensors I had to unscrew the lid and there were additional screws to remove the Pi to get to the SD card. The temperatures were controlled just fine but I play around with the configuration too much for the inconvenience. The cases above looks like better solutions.


#14

I added the case + fan + heatsinks ** jonhawkes2030** linked to above to my attic installation. Below is the graph covering about the first hour after installation. Outdoor temp was around 76F. You can see the temp of the Pi dropped 10C after installation. Not bad.


#15

Looks like the improvement I saw.
Did you get hot CPU alert from FA in the past? If so, please let us know if they go away.


#16

No, I was not getting alerts. I just wanted to take this precaution before the outdoor temps gets >100F at which point the attic is no place for human beings (at least not this one!). For $8 I figured why now.


#17

For the record I bought one of these after I saw your post and replaced my GPIO-controlled fan in the attic. All the parts were decent quality and it seems like a nice open chassis setup with good airflow from the fan blowing down on the Pi. CPU temperature immediately dropped from 120F with no airflow to 80F.


#18

I like the looks of your case for my use and understand SD issue using that case.
My question for you is what are you powering with (how many amp supply)?
May well be my answer for another project here.


#19

Roadfun, sorry to resurrect this so long after your post, but I’m curious how this worked out for you. I’m debating placing my antenna on the roof and direct connecting to the SDR. I’m just south of you in the same type of weather- now that its a year later, I was curious if your SDR was able to tolerate the attic temperatures. Is everything still working ok, even after the hot summer? Thanks!


#20

Yes, the PI+SDR are still in the attic and working fine I did buy one of the fan setups recommended in this thread which does help the CPU temperature. I’ve given thought to trying to find a way to have the antenna and SDR in the attic and the Pi inside the house using a long USB cable but I haven’t tried that yet.