Configuring Arduino IDE for use with Autonomo board and RN2483 Lora Shield

Much of the following set up is from the official Autonomo docs at but with a bit more detail and more screenshots.

Download the latest version of Arduino IDE (1.6.8 at time of writing) from https://www.arduino.cc/en/Main/Software
Extract archive and run the install script which will add an shortcut to the application to your main applications menu.
If you are using Linux you will need to add yourself to the ‘dialout’ user group and logout and login for the change to take effect. This is so that you have permission to access the COM ports.
We then need to tell the Arduino IDE about our Sodaq Autonomo board. The Autonomo’s board profile is available through the Arduino Boards Manager. In order to install the board files you will need to first add the SODAQ board manager URL (http://downloads.sodaq.net/package_sodaq_index.json) to File->Preferences->Additional Board Manager URLs:
Once this is done we need to download the board profile for the Autonomo using Arduino IDE’s board manager.
Search for ‘sodaq’ click install for the latest Sodaq SAMD boards.
You will now see the Autonomo board listed
Now we have the board installed we need to install the Sodaq specific libraries that we are likely to use. We can do this using the library manager:
Search for ‘sodaq’ in the library manager and install the libraries you are likely to use

Your Autonomo board is now configured on Arduino IDE and you can continue development as you would with any Arduino board.

Deploying Keys and Certs to a NodeJS app on AWS Opsworks

I have a nodejs app running on AWS deployed using AWS Opsworks. The app relies on an AWS IoT certificate and AWS IoT private key being present and I don’t want to add the key and certificate to my git repo.

The solution I ended with was to use the AWS Opsworks App environment variables to pass in the certificate and key as environment variables and read these from the nodejs app.

App Environment Variables

Opsworks replaces all new line characters with spaces so in our app we have to reverse this:

var iotcert = process.env.IOTCERT;
var iotkey = process.env.IOTKEY;
iotcert = iotcert.split(" ").join("\n").replace("BEGIN\nCERTIFICATE", "BEGIN CERTIFICATE").replace("END\nCERTIFICATE", "END CERTIFICATE");
iotkey = iotkey.split(" ").join("\n").replace("BEGIN\nRSA\nPRIVATE\nKEY", "BEGIN RSA PRIVATE KEY").replace("END\nRSA\nPRIVATE\nKEY", "END RSA PRIVATE KEY");

…. Problem solved 🙂

I suppose it is a little less secure than the certificate and key being on the file system and with read only access to the nodejs process but it’s a lot more secure than the certificate and key being hosted on github.

Python command history

Obviously iPython is the bee’s kness when it comes to Python shells but if you don’t have iPython installed then getting command history can be a pain. Not any more 🙂

import readline; print '\n'.join([str(readline.get_history_item(i)) for i in range(readline.get_current_history_length())])

This will print all python commands run during that session.

Also as a gist

If you have iPython installed, it’s as simple as

%history

Android must have apps 2015

After a 4+ year hiatus from blog posting. I’m back 🙂 As a first post back I list my ‘must have’ Android apps for 2015.

Airdroid: For copying files (and a lot more) without a cable
QuickPic – very good gallery app
Here Maps – cool GPS that can be used offline
BaconReader – for reddit
File Commander – File browser
MX Player – video player that plays everything
Podcast Addict – for podcasts
Smart AudioBook Player – for playing and managing audiobooks
Impetus – countdown timer for gym
Stopwatch & timer – very good stopwatch
Smart Voice Recorder – neat audio recorder
Yr.no – for weather
Nova Launcher – very fast launcher for Android