Asus RT-N66U: Temperature meassure and graph / Problems

Discussion in 'Tomato Firmware' started by darkknight93, May 3, 2013.

  1. darkknight93

    darkknight93 Networkin' Nut Member

    Good afternoon all!

    I have used my Asus RT-N66U approx 6 Months till now. I always was curious how to Keep my router cool with that Kind of plastic case/narrow space inside the case...

    Here's my recent temperature graph created via rrdtools/rrdgraph


    alias elog='logger -t TEMP -s'
    GETTEMP=`wl -i eth1 phy_tempsense | awk '{ print $1}'`
    rrdtool update /opt/rrd/temp.rrd N:$TEMP
    elog "Ambience Temp: ($TEMP)"

    and rrdcreate:
    rrdtool create temp.rrd --step=300 \
    DS:bandwidth:GAUGE:600:U:U \

    drawing stuff/generating this graph:
    rrdtool graph /mnt/DATA/CIFS/rrd/temp.png \
    DEF:bandwidth=/opt/rrd/temp.rrd:bandwidth:AVERAGE \
    AREA:50#c9feb8 \
    STACK:10#feb8b8 \
    -l 0 -w 600 -h 150 \
    -W "homefs @ $(date '+%F %T %Z')" \
    LINE1:bandwidth#C93434:"Temp" \
    HRULE:60#5f5f5f:"Critical (60 C)" \
    --lower-limit 30 \
    --upper-limit 70 \
    --vertical-label=' C' \
    --title="Asus RT-N66U | PhyTempSense ETH1 " \

    My Setup is the following:


    Using 2 be!Quiet Silent Wings 140mm it only gets cooled to approx 42-45°C ...

    Can anyone post their results from:
    wl -i eth1 phy_tempsense | awk '{ print $1}

    If anyone has tips or might know a way to improve cooling, just let me know :)

    Thanks in advance!
    Taurus_G4 likes this.
  2. darkknight93

    darkknight93 Networkin' Nut Member

  3. Victek

    Victek Network Guru Member

    ;) Put aluminium film in the wall corner to enhance radio 180º and suggest to your neighbor (if someone living behind the wall) to change the head of his bed .....
  4. M_ars

    M_ars Network Guru Member

    nice cooling :)
    Do you overclock your rt-n66u?
  5. darkknight93

    darkknight93 Networkin' Nut Member

    ATM i am running on stock CPU Speed :)

    Thanks for this Input @Victek! In fact I have issues reaching my bathroom with wifi... I'll try the trick with Aluminium foil/film and give Feedback asap :)
  6. Victek

    Victek Network Guru Member

    The water is too hot? ;)
    philess likes this.
  7. darkknight93

    darkknight93 Networkin' Nut Member

    Does anyone know where to buy usb atteched temp sensors? Maybe Ethernet-Based devices? Any temperature sensors which can be addressed/read?
  8. Marcel Tunks

    Marcel Tunks Networkin' Nut Member

    Based on your measurements, the router doesn't need additional cooling.

    If you want better cooling for fun and experimentation, however, ducting is the way to improve the efficiency of a fan. You could construct a rectangular tube with walls made of paper that would encase the routers, tapered at the exit end to snugly fit around a fan. Ideally some further ducting would extend beyond the fan (distance maybe 1.5-2X the diameter of the fan) You wouldn't need the second fan. Depending on the orientation of your wireless clients, 1-2 walls of the tube can be lined with aluminum foil.

    Downsides of ducting
    #1 ugly
    #2 more dust buildup in the ventilation openings in the router cases, ultimately making things worse if you don't clean them
    #3 not needed because the temperatures are fine
  9. RMerlin

    RMerlin Network Guru Member

    Repost of a photo I posted a few weeks ago on another forums. A "typical" evening in my living room ;)


    Regarding temperature, I always say that if it's stable, there is little reason to spend too much time worrying about it. The router was designed with a specific heatsink, so I assume that the Asus engineers are making sure the chip temperature stays within the specifications provided by Broadcom, so long it's in a typical environment.
  10. Toastman

    Toastman Super Moderator Staff Member Member

    Usually, liquid nitrogen will do the trick :D

    (your graphs show the router is running quite cool)
    ryzhov_al likes this.
  11. darkknight93

    darkknight93 Networkin' Nut Member

    :D I really tried cooling with dry ice and got 39°C... not thaaat improvement. Maybe the sensor can not meassure lower temperatures? Don't know.

    Last night I couldn't Keep back and removed the top cover and at first placed the fan sideways - not that huge improvement (43°C) and now with the router tilting a Little backwards and placing the fan in front 39°C

    Might it be possible to cut out the top cover only where the heatsink is? I'll ask asus Support to send me a second top cover, maybe they do and I can give it a try :)

    What is my aim? 20°C. But I dont think this is possible :/


    gives me:

  12. gfunkdave

    gfunkdave LI Guru Member

    I just ran your command on my RT-n66u and got 69 as a result. Surprising since the router isn't overclocked, isn't doing much at the moment, and is just sitting flat with plenty of room around it.
  13. Elfew

    Elfew Network Guru Member

    OMG, so many devices? Do you provide internet connection for all city, not? :D
  14. darkknight93

    darkknight93 Networkin' Nut Member


    Hmm well infact:
    On the wall left: Cable Modem for 100/6 :)
    Left side: Asus RT-N66U for main-Services,
    Middle: Cisco E3200 for DMZ (uses seperate vLan from Asus RT-N66U as WAN)
    Right: SamKnows EU Box for meassuring ISP according to the current europe-wide SamKnows broadband test :)

    I just contacted Asus to send me a new topcover, maybe I'll build a bigger heatsink and do a cut-out on the plastic cover - so the Router case is closed but the heatsink goes through the cover and can be cooled...
    But I have to think about ESD... :/

    Maybe the asus Crew has some other heatsinks/fans or ideas... I'll post the solution I hope to find :)
  15. ryzhov_al

    ryzhov_al Addicted to LI Member

  16. Toastman

    Toastman Super Moderator Staff Member Member

    I don't understand why you do all this work for no gain. It's running at 45 degrees, that is quite cool.
    pharma likes this.
  17. ryzhov_al

    ryzhov_al Addicted to LI Member

    RT-AC66U can be overclocked, RT-N66U - not. Here is modified CFE which can read 64KB NVRAM settings. I've tried every recommended (by Broadcom's SDK) frequency values over 600MHz and wrote down CPU benchmark to this table. Downclocking is possible, overclocking - not.

    Also, there is thermal throttling, prevernting SoC chip to be overheated.
    So, we no need to worry about it's temperature.
  18. vacaloca

    vacaloca Reformed Router Member

    My RT-AC66R is running right now at 57 °C and 66 °C right now, which I thought was a bit hot. I'm hesitant to mod any of the router's internals just to make the temperatures go down though. The top is warm and at some points hot to the touch. Normal for others?

    For some reason I can't see the (englarged) picture posted by the OP... I guess I must need a higher post count, perhaps.
  19. Toastman

    Toastman Super Moderator Staff Member Member

    Stop worrying about it. Remember, this is not a readout of the temperature inside the case. It is a measurement of the actual wireless power output chip itself, we are talking here about something that is completely normal. Chips have internal hotspots, they are designed to run HOT internally, they are designed to run without additional cooling up to at least 75-80 degrees. The manufacturers are not stupid, they do know what they are doing! Look at Rhyzov-Al's tests and u will see what you are doing is completely pointless. Of course, if you like to make huge holes, add power-hungry fans, and destroy your own equipment, it's up to you. But please, guys, don't make everyone reading the forum believe his router is about to melt. There is simply too much disinformation going around as it is.

    This is absolutely ridiculous, really. And it's why I will never add this stupid measurement to my builds.
    Marcel Tunks and pharma like this.
  20. Victek

    Victek Network Guru Member

    What it's out of sense today is to manufacture a device reaching these temperature instead to use a superior CPU as Asus will sale in next model (RT-ac56) to perform the task with lower consumption/heat. The BCM4706 will end life cycle very soon ....

    Few words to stick with, they used some excess of PSU from laptops in their stock (19V DC), to supply 1.2V-2.5V circuitry internally consuming a little bit less than my NAS without any USB device connected (23W). RT-N66 is in the same range. These devices deserves a gold award from North Pole citizens...
  21. ryzhov_al

    ryzhov_al Addicted to LI Member

    9 Watts, no matter of CPU or Wi-Fi load.
    Measured as integral power consumption with this tool.

    PS Checkout my fancy stats:) Now with NAS and UPS.
  22. darkknight93

    darkknight93 Networkin' Nut Member

    My Graphs look like that:

    You can mouseover on specific time - it will Show you the value to that specific time (corresponding Position x-axis)
    Javascript makes it possible :)

    @Toastman: Ok, i appreciate your Input and can confirm - Asus Customer Support (Post Sales) gave the clear Statement: All temperatures ranging from 30°C-80°C meassured by Chip (wl0) are ok. There is no way to stumble around that Point.
    But i use it - might be silly idea - as meassurement for my ambience temp in my room. When sun shines on wooden floor things get warm.
    Small Input by me: Please dont be that offensive.
    darksky likes this.
  23. Victek

    Victek Network Guru Member

    Don't know what model you talk about and the real display of your measure, also I don't like to waste time in discussions. Here are the details, calibrated unit since one month ago. I do calculations using Ohm's law to obtain wats... model RT-N66u

    Volts= x mA = = 15 Wats after 10 minutes warm up. 23 Wats it's at the boot process.

    PS. Do you have a reliable instrument?....

  24. kthaddock

    kthaddock Network Guru Member

    You measure on different place Ryzhov mesure on AC side (110volt) and Vicktek on DC side (19volt) depend which powersupply you use, eg serie regulated or switched. Most accurate is on DC side.

  25. Victek

    Victek Network Guru Member

    As it's per rules... ;)
  26. ryzhov_al

    ryzhov_al Addicted to LI Member

    This is right only for a resistive load. You have to use watt-meter to get correct values.
  27. Victek

    Victek Network Guru Member

    As I said I don't discuss .. the router is not a resistive load since the PSU internal is PWM 2phases at 85KHz frecuency conversion and these values are measured at DC jack, not at the AC side. But if you say 9Wats I'm OK.. ;)
  28. RMerlin

    RMerlin Network Guru Member

    Bottom line: temperature is normal, just don't worry about it. :)

    (My previous WRT310N was warmer to the touch than my RT-AC66U BTW)
  29. jan.n

    jan.n LI Guru Member

    >Can anyone post their results from:
    >wl -i eth1 phy_tempsense | awk '{ print $1}
    10 active wireless clients, 3 wired ones...
  30. ryzhov_al

    ryzhov_al Addicted to LI Member

    Nevermind, it's brain fart on my side. I forgot power supply got DC output.
  31. kthaddock

    kthaddock Network Guru Member

    Hehe No problem, welcome to "the club" :confused:
  32. Planiwa

    Planiwa Network Guru Member

    Can someone explain why the wl command does not simply return the temperature in degrees Celsius? Is it because dividing by 2 and adding 20 would be too "inefficient" for the driver to do?
    darkknight93 likes this.
  33. RMerlin

    RMerlin Network Guru Member

    Most likely because the register returns the straight thermistor value, and the value can change either between chip models, driver versions, or based on external components on the PCboard.

    This is the same with Intel CPUs BTW. The internal temperature is returned as the difference between Tjunc and the current temperature. You have to do the math to get the actual CPU temperature - Tjunct can vary between CPU models.
  34. darksky

    darksky Addicted to LI Member

    Just found this thread. Temp sensors in my RT-N66U rock.

    # Display the temps of both broadcom chips in an Asus RT-N66U[/COLOR]
    # Requires a custom firmware such as tomatousb running an ssh server
    # Credit to the original author: darkkight93
    GETTEMP1=$(wl -i eth1 phy_tempsense | awk '{ print $1}')
    GETTEMP2=$(wl -i eth2 phy_tempsense | awk '{ print $1}')
    if [[ $(echo "$GETTEMP1" | grep -c Not) -eq 1 ]]; then
        echo " ==> Radio is off so cannot measure temps."
        exit 0
    echo "eth1 is $(((GETTEMP1/2)+20)) C"
    echo "eth2 is $(((GETTEMP2/2)+20)) C"[/COLOR]
    Are there any other temps I can query aside from the two wi-fi chips?

    FYI, my output:
    # temps
    eth1 is 52 C
    eth2 is 53 C
    darkknight93 likes this.
  35. darksky

    darksky Addicted to LI Member

    This is very nice. Do you have the code for it on github or elsewhere? I have been using rrdstorm which I found in this thread, but your screenshot seems pretty nice.
  36. darkknight93

    darkknight93 Networkin' Nut Member

    Thank you :) i appreciate your interest, due this was a little struggling for me as Linux-newbie

    This page is based on cgi scripts attached in (you might remove my links to other Monitoring subpages like IPTables/Syslog/KD stats)

    Place them in /var/www/ext/cgi-bin/* and open them via http://routerip/ext/cgi-bin/cputemp.cgi

    It opens the .rrd file in:
    my $rrdfile="/mnt/DATA/scripts/rrd/dbs/cpul.rrd";
    my $rrdfile2="/mnt/DATA/scripts/rrd/dbs/temp.rrd";
    ... and calls a rrddump to get raw data out of the rrd. So you might Need to edit the .cgi file to correspond to your Location of your rrd databases

    in the there's the Background and style.css ;) this is optional, so you don't Need to use it (place them in /var/www/ext/*)

    My rrd databses look like:
    rrdtool create /opt/rrd/temp.rrd --step=60 \
    DS:temp:GAUGE:180:U:U \
    CPU Load
    rrdtool create /mnt/DATA/scripts/rrd/dbs/cpul.rrd --step=60 \
    DS:temp:GAUGE:180:U:U \
    Collecting scripts:
    alias elog='logger -t CUSTOM_CPULoad -s'
    load=$(cat /proc/loadavg | awk '{print $1}')
    rrdtool update /mnt/DATA/scripts/rrd/dbs/cpul.rrd N:$load
    alias elog='logger -t CUSTOM_Temp -s'
    GETTEMP=`timeout 2s wl -i eth1 phy_tempsense | awk '{ print $1}'`
    if [ $TEMP -eq 0 ]
     elog "ERROR: Failed to read ambience TEMP"
     rrdtool update /mnt/DATA/scripts/rrd/dbs/temp.rrd N:$TEMP
    i ran this .sh via Sheduler every 1 Minute.

    For running Perlbased scripts like that you Need to install them via opt/entware:
    opkg install perl
    opkg install perlbase-base
    opkg install perlbase-essential
    opkg install perlbase-autoloader
    opkg install perlbase-config
    opkg install perlbase-config
    opkg install perlbase-getopt
    i hope i included all neccessary Information. If you Need further Details, just reply to this thread or PM me

    Attached Files:

  37. Planiwa

    Planiwa Network Guru Member

  38. rootMBX

    rootMBX Networkin' Nut Member

  39. Quint

    Quint Serious Server Member

    Thanks Darkknight93. It does make a difference, but maybe tearing your router apart is too extreme ;-)
    My RT-N66U runs at 53C and am thinking about adding a small fan for active cooling.
    This desire comes from my use of the RT-N16, and it's over heating problems.
    MY RT-N16 overheated twice. First time was a router replacement. Second time, the flash memory was gone!
    I use the wireless temp, as an overall indication of how hot the internals are getting: CPU/RAM/Flash...
    Even on the hottest days, my wireless on the RT-N16 now only gets to 42C :)
    I did something similar to the link below, and will replicate to the RT-N66U

    Thanks again Darkknight93.
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