Actvities at the lab

SSL/TLS Client Certs to Secure MQTT

posted Feb 13, 2015, 7:53 PM by JERRY DUNMIRE   [ updated Feb 13, 2015, 7:55 PM ]

The exercise is a step-by-step procedure to generate client certificates for use with MQTT. The mosquitto broker and command line clients are used to demonstrate certificate use.

OpenVPN Community Edition on an AWS EC2 instance

posted Feb 8, 2015, 7:58 AM by JERRY DUNMIRE   [ updated Feb 8, 2015, 8:06 AM ]

While travelling last summer I wanted a way to secure my network access while using open WiFi access points. After a bit of research I decided to run OpenVPN on a free AWS EC2 instance.

Full details for this exercise, including several scripts and sample configuration files are available from

HC-05 Recovery

posted Jan 29, 2015, 7:14 PM by JERRY DUNMIRE

The HC05Recovery exercise explains how you can restore communications between an Arduino UNO and an HC-05 with incompatible serial port settings.

Privacy Policy

posted Jan 1, 2015, 2:11 PM by JERRY DUNMIRE

I have been wondering how much this site is used by others and decided to experiment with Google Analytics to find out. Since Google Analytics collects data visits to this site, the service requires me to tell you about what data is collected and how I use the data. I.e., a Privacy Policy.

In addition to the link in this post, you will always be able to find a link to the policy in the Navigation bar to the right.

Working with a cluttered desktop

posted Oct 26, 2014, 11:39 AM by JERRY DUNMIRE

Using a mouse button to activate the Unity Spread function is an easy way to find the window you want when it is buried deep on your cluttered desktop. But, finding the controls to bind Unity Spread to a mouse button is difficult due to inconsistent terminology.

The Ubuntu and Logitech M705 buttons exercise is a step-by-step procedure for setting up the mouse button binds for a Logitech M704 mouse.

First 24hrs with Raspberry Pi and WSPR

posted Aug 25, 2013, 10:12 AM by JERRY DUNMIRE   [ updated Aug 25, 2013, 10:29 AM ]

It works! I have a Raspberry Pi transmitting WSPR and it has been heard.

Map from WPSRnet

Using WsprrPi is easy- to transmit on three different bands in rotation with frequency calibration using NTP  the command line I used is:

$sudo ./wspr -r -s KA6HLD CM97ai 10 20m 30m 40m

The set up is cobbled together and strung out over most of my shack. I used the JamesP6000 version of the WsprryPi program, a low pass filter from Kits and Parts dot Com that I analyzed in the  RF Filter for a Raspberry Pi Transmitter exercise, and my MFJ Multi-band vertical.

The vertical is not in good shape (broken counter poise wires and other problems) and I didn't check the SWR. Still, the 10mW signal from the Raspberry Pi was heard on 2 bands by 4 different stations. W0AY, on 30m in Montana, recorded the most reports (63) over the first 24 hours. Reports on 20m were from N0HAV, K0SQL53, and  the distance winner (2041 km) VE6PDQ.

This has been great fun and I recommend that anyone with a Raspberry Pi and an Amateur Radio license give it a try.

Next I need to look into WSPR reception...

RF Filter for a Raspberry Pi Transmitter

posted Aug 20, 2013, 9:18 PM by JERRY DUNMIRE

The RF Filter for a Raspberry Pi Transmitter exercise analyzes two filters in order to choose a filter for use when transmitting a WSPR signal using the Raspberry Pi.

HC-05 Library

posted Feb 10, 2013, 8:50 AM by JERRY DUNMIRE   [ updated Feb 10, 2013, 8:54 AM ]

I put together an Arduino library for the HC-05 Bluetooth to Serial module. It includes methods to automatically determine and set the HC-05 baud, issue AT commands to the module, and connection based blocking output.

The library can be configured for use with hardware or software serial ports. The library code is available at GitHub and there is a descriptive exercise here.

Arduino and the LCD Breakout Board

posted Jan 21, 2013, 9:56 PM by JERRY DUNMIRE   [ updated Jan 21, 2013, 9:57 PM ]

This exercise connects a Color LCD Breakout Board from SparkFun Electronics to an  Arduino UNO. Sketches in the exercise demonstrate the tri-color LED, switches, and the color LCD. The exercise addresses +3.3v to +5v level translation for each of the devices and discusses driver selection and alignment for the LCD.

The gLCD library by Tom Carpenter  is used for communicating with the color LCD.

Source code for the sketches presented in this exercise are available at GitHub.

Comments are welcome at the RockingD Labs Community on Google+.

myHikes - an exercise in mapping

posted Jan 7, 2013, 7:26 PM by JERRY DUNMIRE   [ updated Jan 21, 2013, 9:35 PM ]

Castle Rock Hike


This project plots the tracks I've collected with myTracks on maps built using OpenLayers. The design of the website itself, using Bootstrap, is part of the project.

At this point the site is up and running with more than 3 years of tracks.

Future work will include:
  •  Make it easier to find a desired track- perhaps through the use of an overview map.
  • Create an automated way to add and upload new tracks.
  • Search out and enable alternative topographic base layers that give elevations in feet (for the US) rather than meters.
  • Add summary information such as the number of tracks, total distance and total time.

Comments are welcome at the RockingD Labs Community on Google+.

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