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Who's at the door  Hans and Matilda were fast asleep when they heard a knock at the door. He put on a robe and wandered over to the door. "Who is it", he asked, "The postman" replied the stranger. Hans peered through the spyhole and saw the cap of the postman. Why is the postman visiting in the middle of the night thought Hans? He looked again, below the cap he saw a large pair of eyes, above the cap he saw a large pair of hairy ears and through the darkness he saw a large set of sharp teet ...
Hans also found the "pretty-wifi-info.lua" script for checking the Yún's WiFi status, it nicely abstracted Hans code from the hardware so he wrote a wrapper for that rather than writing his own. He used the "parse" module to interpret the output. That installed nicely on the Yún for a change.   pip install parse   To avoid key errors he defaulted all of the common values to be "unknown". # Get the Wifi Status into a dictionary import subprocess from parse import * d ...
Good morning Ricksville  One morning Farmer Hogg woke up, looked out the window and checked the colour of his field.He headed down to the kitchen and turned on his internet radio, Rick Astley was playing so he turned it off again. Old Mother Hubbard turned on her computer to check her inventory management system. A Rick Astley video was playing, she liked Rick so left it playing and forgot what she was about to do. At the top of the stairs, around the back of the town hall, the man from t ...
Just spotted this, it's the Yún but in a smaller form factor.   http://arduino.org/products/arduino-yun-mini   Also spotted it's by the Arduino.org team not the Arduino.cc team if you care about such things. ...
Putting the Arduino Yun to sleep  Hans and Matilda thought back to the Golem and how he slept between each activity, that could also work for their Yún.    The key things were:   Turning the Linino power off Turning the Linino power back on Low power on the ATMega side Waking back up. Timers and servo.   Poweroff is not enough  The Linino O/S uses BusyBox for a lot of the tasks of it's shell. One of these is the "poweroff" command. http://www.busybo ...
C.Defeo's Decorating and Building Merchants  Hans and Matilda wanted some sheet metal to build the battery box so popped down to C.Defeo's Decorating and Building Merchants for supplies. The shop keeper advised them that he only had large sheets but he'd cut them for free. He lead Hans and Matilda to the yard out back where the massive sheets of stainless steel were stacked. Hans and Matilda looked up at the sheets and could not work out how the shop keeper was going to move them. He pulled ...
As mentioned in a previous installment Hans was having some trouble installing the secure version of the requests module for python, it didn't matter what he tried there always seemed to be something that needed a different version of a tool installing or a script that did not want to run correctly. So Hans took some steps back and wrote the code to get the weather instead.   Thinking about the reason for using requests in the first place it was to make the code simpler, however the functi ...
I've mentioned before that we are not the only ones determined to enchant some objects.   Simon Morris has made floating lightbulbs powered by induction.     via: http://makezine.com/2015/05/03/making-lightbulbs-float/ ...
A useful presentation on securing your devices   Defining the Internet of Things (10:27) Unprotected devices will be attacked (13:15) Encryption (15:46) Single security model for all communications (17:56) Access control (20:13) Tracking device metadata (21:14) Provisioning in the field (22:38) Firmware updates in the field (24:07) Compliance with regulations (25:15) Reinventing the wheel (26:17)   http://blog.atmel.com/2015/05/04/the-10-challenges-of-securing-iot-communicat ...
The next challenge for Matilda was a temperature gauge, she'd planned to use an LED bargraph for this but was concerned it would "light up the house like a Christmas tree". Her next thought was a servo driven slider pointing at a scale. There was not much room for this so she wondered if she needed to bother with a Fahrenheit scale. She'd ask the oldest person she knew which was Farmer Hogg. It was lunch time so she knew where to find him, in the Adam and Eve.   Farmer Hogg  Matilda a ...
Hans was struggling with installing requests[security] the compile issues seemed to keep coming back like a hydra regrowing its heads.   To take a break he went to visit his friend Albert. Albert invited Hans in and disappeared into the kitchen to make some tea. "Make yourself at home" called Albert from the other room. Hans sat down on the sofa next to a grey cat. It looked friendly so Hans went to pet it. As soon as he moved the cat stretched out its paw and out shot the claws. Hans reco ...
Ever since the storm Hans and Matilda's power supply had been quite flaky. The electricity company had sent engineers round several times who found and fixed loose connectors and faulty wiring deep in the forest. But the problems kept occurring so Matilda was keen to get their battery based supply up and running.   The Blue Haired Woman  On the day that Matilda planned to connect up the Yun they had a knock on the door. Hans opened the door and was greeted by a large blue ball of fu ...
I discovered this morning that back in 1945 there was a film called the "Enchanted Cottage" perhaps there will be a remake? ...
Package Manager All modern Linux distributions come with a package manager such as Yum or RPM. The Linux distribution included on the Arduino Yun is no exception. It uses OPKG (Open PacKaGe manager). To get an upto date list of package you use the command opkg update to list the package available opkg list and there's install, update and remove commands for actually managing the packages. The instructions are covered in details in the link above.   Configuration You can change the behaviou ...
Currently...  Whilst Hans was busy coding, Matilda was looking into power requirements. She was worried that the batteries might take a long time to deliver so wanted to order them long before they would be needed.   Device Power Required Arduino Yun 300mA MicroSD Card 100mA Infineon RGB LED controller 9mA Servo 100mA RGB LED 20mA per colour 60mA   Totting up the numbers she arrived at 569mA peak consumption, she realised that by turning things off and running tasks in series tha ...