Docker Official support for Raspbian/Jessie

docker release 1.12  – finally adds support for raspbian on Arm. This is good news for Raspberry Pi. should make it easier for lot of folks to try their hand at containerization. The details are here .

Brought to you by the same folks at Hypriot. Who get into details here. Earlier the only way to get docker on RPi was to get HypriotOS.

OctoPi – Under Voltage issues



Have been struggling a lot with unreliable WiFi and more recently not being able to reconnect to router even after rebooting. Since the Octopi runs purely in headless mode I always suspected WiFi signal strength issues to be the cause for OctoPi going off my network and not being able to reconnect.

This is after trying to resolve signal coverage and strength issues by getting a signal extender which improved coverage and signal quality.

Connected to a monitor to troubleshoot.

Got a warning

fsck: Warning... fsck.vfat for device /dev/mmcblk0p1 exited with signal 6.
fsck died with exit status 8

Went into a rabbit hole of googling sd card errors and recovery procedures till I came across a forum posting where someone just mounted the sdcard on a windows machine and fixed the problem automagically. Guess what I do have a Win 8.1 machine. No harm in trying. As soon as the sd card was mounted windows detected that there was something wrong with it and graciously offered to fix it. Took the fixed card back to RPi and waited with a bated breath for it to boot up. To my surprise it booted up perfectly with no errors. So here is another anecdotal evidence supporting the automagical sd card healing properties of Windows.

But the elation was short lived. Got the omnius Rainbow Square on top right. Not steady but pulsating.

On researching found this Raspberry Pi • View topic – Under-voltage warnings. Note that it is being powered by a 2A supply from MCM. 

The warnings could be triggered both by power supply and usb cable.

So if you are running headless (which is usual with Octoprint) you have no way of knowing about the under voltage issue. Mike Redrobe has a solution to monitor this remotely.

I am suspecting the microUSB cable (microcenter) which works well for charging my umpteen other devices but somehow fails here. The only other device connected is the Edimax wireless dongle and RaspberryPi Camera.

OctoPi : Wi-Fi doesn’t reconnect automatically



Flaky WiFi issues still persist. Trying this to see if it would remedy the issue.

ssh into your pi (or use a monitor and keyboard :-))
then type the following (or copy paste it):

mv /etc/ifplugd/action.d/ifupdown /etc/ifplugd/action.d/ifupdown.original
ln -s /etc/wpa_supplicant/ /etc/ifplugd/action.d/ifupdown


Source: Wi-Fi doesn’t reconnect automatically · Issue #211 · guysoft/OctoPi

Octoprint : Changing RPi camera resolution


, ,

1. SSH to your RPi using either Terminal or an utility like Cyberduck with username of “pi” (if you haven’t changed the default username) and your password.
2. Then enter following commands:

cd /root/bin
sudo nano webcamd

3. Then look for the following entry

camera_raspi_options="-fps 10"

4. Comment out the existing line in case you would like to revert back the
changes. x & y options give the resolution. The RPi camera can do 1080p30
but 720p is good enough for me.

camera_raspi_options="-fps 10 -x 1280 -y 720"

5. Press Ctrl + O, Enter to save and then Ctrl + X to exit

6. Reboot with:

sudo reboot

PrintrBot Issues: Z axis misalignment



My PrintrBot z-axis got misaligned when I inadvertently left something on the printer bed after sending a new print to be printed. Did not realize till I heard the grinding noise. I cut the power but it was already too late. Upon restarting, the Z-home was almost an inch away from the bed.

Watched couple of videos on z calibration. Manually brought down the hotend till it was almost touching the bed and then fired up the auto leveling wizard. Tried a cube print first to see if it would turn out to be ok. The resulting cube was 0.3 short all around (from earlier reference cubes printed).

The M501 command showed that the Z axis was compensated almost -1.25.

> M501
< echo:Stored settings retrieved
< echo:Steps per unit:
< echo: M92 X80.00 Y80.00 Z2020.00 E93.50
< echo:Maximum feedrates (mm/s):
< echo: M203 X125.00 Y125.00 Z5.00 E14.00
< echo:Maximum Acceleration (mm/s2):
< echo: M201 X2000 Y2000 Z30 E10000
< echo:Acceleration: S=acceleration, T=retract acceleration
< echo: M204 S3000.00 T3000.00
< echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
< echo: M205 S0.00 T0.00 B20000 X20.00 Z0.40 E5.00
< echo:Home offset (mm):
< echo: M206 X0.00 Y0.00 Z0.00
< echo:PID settings:
< echo: M301 P22.20 I1.08 D114.00
< echo:Min position (mm):
< echo: M210 X0.00 Y0.00 Z0.00
< echo:Max position (mm):
< echo: M211 X152.40 Y152.40 Z152.40
< echo:Bed probe offset (mm):
< echo: M212 X25.00 Y0.00 Z-1.25


Took a wild guess and adjusted the Z-axis offset by 0.5

// Reset Bed probe offset (mm)

M212 X25.00 Y0.00 Z-1.20

// Save settings

Tried cube after the reset the offset, much better z-axis 3.01 to 3.02 all around.

PrintrBot Tips



My Upgrades so far

  1. Cooling fan shroud – The one from getting started guide did not work well for me so printed the Improved fan shroud that surrounds the Hotend.
  2. Spool Rack Spacer (from Getting started guide)
  3. Raspberry camera bed mounting post
  4. Printrbot Simple Metal Small Feet
  5. Improved PB Fan Shroud
  6. Compact Raspberry Pi Case
  7. Raspberry Pi mounting clip


  • Blue Tape (3M #2090)
  • Rubbing Alcohol
  • Putty Knife (though I find box cutter works better with its sharp edge to get under the prints),
  • a air tight box for filament with dessicant.
  • Raspberry PI w/ wifi dongle, Raspberry Camera and Octoprint (offloads the printing from your PC/Laptop).

Misc Tips:

  • Cleaning the metal top with alcohol prior to applying the tape to remove any adhesive residue may prevent the tape from pulling up during prints (i did not encounter this issue but tried it nevertheless, keeps adhesive buildup from Blue Tape) .
  • if printing ABS – wipe the Kapton with Acetone, if printing PLA – wipe the Kapton with rubbing alcohol
  • I print PLA mostly 195 and 45 mm/s. I find that 195 works for most of the filaments I have tried.
  • Wait for the bed temp to equalize with room temperature after printing is done. Prints just pop off without effort. For flat prints, I use boxcutter to pry an edge till it just pops off. For taller prints I just have to twist the print and it pops off.

Wish List

  • PrintinZ – Eliminates blue tape and surface prep for printing. Will try it out once I’m confident in fiddling with calibration.  Upgrade for PrintinZ – Plate clips to attach to Printrbot



Printing Curiosity Rover


NASA has made available various 3D printable models that can be downloaded and printed by hobbyists. Wanted to try out Curiosity Rover on my PrintrBot. The supplied models come in two sizes. The large is too big for PrintrBot Simple. So decided to try out the small version.

Body, Arms and Legs were printed with Hatchbox White PLA. While the wheels are printed with Toner Plastics Red PLA. The settings are same for both of them.

Curiosity Rover PrintedCuriosity Rover Assembled


PrintBot Simple Metal with Heated Bed

Filament : Hatchbox White PLA, Toner Plastics Red PLA

Layer Height : 0.1984

Print Speed : 45

Print Temperature : 195

Bed Temperature : 65

Curiosity Rover : NASA

Curiosity is a car-sized robotic rover exploring Gale Crater on Mars as part of NASA’s Mars Science Laboratory mission (MSL). Curiosity was launched from Cape Canaveral on November 26, 2011, at 10:02 EST aboard the MSL spacecraft and landed on Aeolis Palus in Gale Crater on Mars on August 6, 2012, 05:17 UTC. The Bradbury Landing site was less than 2.4 km (1.5 mi) from the center of the rover’s touchdown target after a 563,000,000 km (350,000,000 mi) journey.The rover’s goals include: investigation of the Martian climate and geology; assessment of whether the selected field site inside Gale Crater has ever offered environmental conditions favorable for microbial life, including investigation of the role of water; and planetary habitability studies in preparation for future human exploration.

Source:  NASA| 3D Resources (Beta)

Backed CowTech Ciclop – Open Source 3D Scanner 


, ,

Was looking into 3d Scanners. Makerbot makes one that is $799 but did not feel like shelling out that much and their approach to open source. The Ciclop is a open source design by a spanish company BQ who also sells a kit by the same name. This kickstarter takes their design and has made it more affordable. This is ofcourse based on the assumption that the backers will be printing their own 3D parts for the scanner.

$99 gives you everything except for 3D printed parts.

Thingiverse had the the 3D printed parts published by BQ.