RaspberryPi Heatsink

This might become a series because I am trying to find some results.

Electronics temperature is not an exact science. Yes failures happen when temperatures hit an absolute max, but you can still have stress on electronics based on how long it is “hot”. For example: a device operating at temperature_ambient=25C will outlast a device operating at ambient=25C.

My philosophy is to keep things as cool as conveniently possible. Which is why the Pi is frustrating at times. There’s no heatsink. It’s a chip in the center of the board and that’s it. No fins, no large pads radiating heat away.

And it’s not cool to your finger either. It’s surprisingly warm to touch. Of course the next step is to find the temperature of the device. Try running a command like this:

/opt/vc/bin/vcgencmd measure_temp

My apartment is currently ~16C. My Pi0 stashed in the near vicinity of an access point is reading 32.0C. It’s not a perfect measurement because the accuracy of the chip varies in 0.5C steps. I will have a cron job set up eventually and clean up the data in python for the next blog post. Either way, it is still has a temperature rise of 15C above ambient.

I have another Pi that is in my living room (where I am getting the ambient temperature measurement). This Pi has a heatsink with the Arctic Silver Thermal Adhesive product and a small aluminum heatsink from Alibaba. It has temperature readings of 29.3C, still temperature rise of 15C above ambient.

Some factors that "may" be related:
* Pi1 is running a CUPS server.
* Pi1 is crammed into a corner next to the printer.
* Pi2 has no peripherals plugged into it

Questions left open:
* Pi1 has thermal adhesive, maybe it's not applied well?
* Pi1 has adhesive on the plastic body "chip top", maybe thermal resistance from the die to the top is too high to get benefits?
* How is the measurement done for the temperature in the Pi's?
* Is it worth having some temperature sensors to monitor the temperature in my apartment to have a good baseline to compare the Pi measurement to?

HP Pavilion 15t - Disassembly Tips (disk drive)

I've put the dimensions in for HP part "DVD/CD REWRITABLE DRIVE", model DU-8A6SH, part number 700577-HC2

My intent is to replace it with a hard drive "caddy", such as these links from amazon:

http://www.amazon.com/Drive-Unibody-MacBook-SuperDrive-Replacement/dp/B0058AH2US/

http://www.amazon.com/Adapter-Special-Designed-macbook-SuperDrive/dp/B0057V95M6/

http://www.amazon.com/WoneNice-caddy-9-5mm-Universal-DVD-ROM/dp/B004Y8SGXW/

Figure 1: Measurements of original drive

If anyone knows how to keep the drive secure in the chassis, that would be great. Is the tab in Figure 1 "top" something standard?

USB3 Ethernet Adapter

Just bought Vantec CB-U300GNA based on this review. I have need of one because my old laptops only have 10/100 ethernet and the standard RJ45 plug gets stuck in my computer jack. I worry about the 100Base-T since I am paying for 50Mbps connection speed. For $18, it's not too risky an investment and should give me plenty of overhead for my 50Mbps internet connection and any other sharing I want to do behind my ethernet hub.

One thing nice about having a USB ethernet module is being able to have one single MAC address to access my router's administration page (that is, blacklist all other MAC addresses to keep it relatively secure). Now whenever I need to access my router's administrative page, I plug in any computer to that USB ethernet adapter and I'm off and running.

The adapter claims to have wake-on-LAN, which is a feature I always wanted to test out. Never tried waking a computer up over USB, but there's always a first for everything? Will update in the future if I ever get around testing it.

Handy Window Scripts

Here's my script that I run on my computers to standardize my home experience:

@echo off
rem map router's network share to the same letter drive on every computer
net use z: \\192.168.1.1\volume1\local_share

rem create shortcut targetting my plex server web interface
rem this assumes that you will only have one user
echo start iexplore.exe http://192.168.1.254:32400/web/index.html >.\Desktop\launch_plex.bat

Converting Windows Laptop to 2k8r2 Server

I got this idea from the official blog. I can think of an improvement though: why not just copy over those directories before installing the new OS? That way, you don't have to deal with partitions.

If you can install an OS, then you have a media that is accessible to load all the drivers (even better to make a disk of just the bare drivers, even if only one instance of time).

The steps would be something like this:

1. Create/Obtain installation media for target OS.
2. Transfer contents of C:\Windows\System32\DriverStore\FileRepository to the same media type as target OS installation media.
3. Boot from installation media of new OS.
4. Install the new OS
5. Go to device manager of new OS and for each missing driver, load from exported data of step 2

I will try this in the future and let you know how it goes. Right now, I have a Lenovo Z580 Win7 machine that I only access via VNC: no point in dedicating resources on the machine for a GUI that's never used, right?

HP Pavilion 15t - Disassembly Tips

For the laptops first released in 2015-Q3: please be careful not to damage the hinge when removing the chassis cover.

The new bottom cover now wraps around the laptop. It makes disassembly more challenging as it is not just pull up or push in a certain direction. I had been following another guide, youtube1, youtube2, but the instructions don't match so I probably wasted upwards of two hours before wiggling the bottom lid finally detached.

The plastic tabs held up OK considering how much abuse I had given them.

See the pictures below:

Figure 1: new chassis, notice vent pattern to identify from other models

Figure 2: close up on bottom cover in the entire laptop assembly

Figure 3: inside of bottom cover at the left hinge wraparound, picture taken from center above keyboard

Figure 4: inside of bottom cover at the right hinge wraparound, picture taken from center above keyboard

 PS, I have not been on blogger for a very long time, the edit interface is very amazing from what I remember from years ago

SB6141 Dim Activity Light (DIY)

source: http://thisdoesnotcompute.org/2013/10/06/fix-for-blindingly-bright-motorola-cable-modem-lights/

I used his method to open up the box. My only improvement is suggesting aluminum foil, wrapped around the "lighting guide" on the front panel.

I attempted to use sharpie on the board LED, but afraid of increasing the thermal resistance to the LEDs. I was going to use electrical tape, but none in my lab yet. Either way, aluminum foil is light, interrupts the light path, but low thermal resistance.

I would recommend replacing the resistors with higher values but... just in case the changes are evident in the board, I opted not to use this method (also, 0201, please correct me if I'm wrong, parts are a little bit out of my comfort range).

Future things I would like to do when warranty is out: replace heatsink because somehow the modem generates plenty of heat and replace load resistor to the LEDs to dim in a more efficient manner.

Any other suggestions?