Setup for MakerFaire 2015

At the Tinaja Labs booth, called The Sense of Things, I had a full IoT system (Internet of Things) in place. Front to back I started with wireless sensors, to a Raspberry Pi that collected sensor data, to a Beaglebone Black running Node-Red (as a signal routing application), to newly introduced inexpensive wi-fi modules (the ESP8266), and finally to old-school X-10 light switches.

I’ve always described my setup as a home automation system that is built on a wireless sensor network.  I first heard about the concept of the Internet of Things (IoT) in 2009.  Home automation and wireless sensor networks are now included in the overarching concept of IoT and includes M2M (machine to machine) and industrial applications like manufacturing systems.  IoT describes all the things that can be connected through internet technologies with sensors on one end, actuators on the other end and coordination software in the middle.

Overview of the IoT system

Download the OS image here. Read instructions here and learn about how to burn an OS image to a MicroSD card using WinDiskImager32.  More info about setting up a MicroSD card here.

The system in place includes examples of typical components of an IoT system.  On one end I had wireless sensors (based on XBee Series 1 radios), in the middle I had connecting and coordination system software (Node-Red), and on the other end I had charting and analysis (Graphite/Grafana) and actuation (wi-fi based LED control).  Pretty much, that covers the basic areas of home automation.

Code for this setup is on Github at:  TinajaLabs/makerfaire2015

Sensor PCB with XBee

the MS-1 PCB

My MS-1; a Multi-Sensor PCB w XBee.

I designed this PCB a few years ago and it still works great.  I deployed these in every room of our home.  It has a 3.3V regulator, an XBee Radio, a temperature sensor (tmp36), a light sensor (CdS cell), and headers for 2 more sensors (mostly I’ve hooked up a hall effect sensor and an FSR, force sensitive sensor).  I also included a rail to rail buffer chip to create a clean separation between the sensors.  In hind-sight I probably didn’t need that.

The sensor board schematic and the PCB layout:

MS-1 PCB Layout

MS-1 Schematic

Using XCTU, a configuration tool (available for Windows, Mac, or Linux) from Digi, I configured the XBee Series 1 radio end points like this:

ID=1111 (same for all radios in your system)
CH=0C (same for all radios in your system)

Wi-fi Capacitive Touch Button

Download the OS image here. Read instructions here and learn about how to burn an OS image to a MicroSD card using WinDiskImager32.  More info about setting up a MicroSD card here.

This is a new sensor setup, breadboarded, that uses a capacitive touch switch (Standalone Toggle Capacitive Touch Sensor Breakout – AT42QT1012) and an ESP8266 wi-fi PCB.  The capacitive switch responds to touch and toggles a high/low voltage  on the GPIO01 pin of the ESP8266.  The ESP8266 is programmed to send the switch’s state over wi-fi to a web service on the Node-Red software.  More about that in the Node-Red section below.
django-tagging 0.3.1 or greater


Here’s the Fritzing breadboard of the capacitive switch hooked up to an ESP8266. Find the code I used code on Github.

The Gateway “Stack”

The picture below shows what I call my gateway rack (constructed from a CD caddy and CD sized pieces of colored Plexiglas from Tap Plastics).  All of the functionality could probably be included on any one of these devices, but for the sake of experimentation and separation of functions, I set up 3 micro-computers:

  1. Raspberry Pi B+ (on red Plexiglass):  Has a GPIO board from Ciseco called the Slice of Pi that supports an xbee coordinator configured radio.  It is running  Raspbian OS and a python script that collects the serial data being collected by the XBee radio.  The metric data is collected, bundled up and formatted, and sent to a Node-Red TCP Socket module.  It also has an application named mochad-0.1.16 that provides X-10 device connectivity.
  2. Beaglebone Black (on blue Plexiglass): Running Debian Wheezy and installed with Node-Red (requires Node.js; should already be installed on Wheezy)
  3. Odroid C-1 (on orange Plexiglas): Running Ubuntu 14.04.2 LTS with Graphite and Grafana installed to provide a data store and data charting for all the sensor data.


When loading up an OS on these gateway devices, the basic process is to load an image file onto a MicroSD card that stands in as the computer’s bootable hard disk.  I prefer using Win32 Disk Imager and I found ApplePi-Baker to be useful on Mac OS X.  There’s a great overview of different methods here:

Sensor Gateway

Download the OS image here. Read instructions here and learn about how to burn an OS image to a MicroSD card using WinDiskImager32.  More info about setting up a MicroSD card here.

The Raspberry Pi sensor gateway has a GPIO PCB from Ciseco, the Slice of Pi, that supports an xbee radio.  This XBee radio is configured to be the coordinator radio for all my XBee Sensor PCBs (described above).  There is a python script,, that reads the data being received from the XBee radio via a serial port.  Sample code on Github.

Using a software configuration tool from Digi (manufacturer of XBee radios) called X-CTU, and an XBee FTDI device (from AdaFruit, or Sparkfun – FTDI friend needed), you can set the configuration of the XBee modules.  Here are the critical settings for my setup:

ID=1111 (same for all radios in your system)
CH=0C (same for all radios in your system)

To start the python script whenever the Raspi boots up, you’ll need an init script.  Find a sample on Github.

Once you place this file in /etc/init.d, run this command:

# update-rc.d tinaja_sensor defaults

Once this is set up, the python script will start-up at boot-time, or you can manually start and stop the script when you make changes like this:

# service tinaja_sensor stop
# service tinaja_sensor start

Node-Red Gateway

This gateway was built using a BeagleBone Black, Revision B.  It is running the OS, BeagleBone Debian.

Download the OS image here. Read instructions here and learn about how to burn an OS image to a MicroSD card using WinDiskImager32.  More info about setting up a MicroSD card here.

Download the OS image hereRead instructions here and learn about how to burn an OS image to a MicroSD card using WinDiskImager32.  More info about setting up a MicroSD card here.

Node-Red is a web based application with a drag-and-drop user interface that makes it possible to build data flows by dragging various components on to the design surface (http web services, tcp socket listeners, MQTT, functional blocks, format converters, etc.) and connecting them with rubber-band connectors that direct the “flow” of data between components. node-red-sample1

This gateway device is responsible for managing the connectivity and the logical flow between the sensors and actuators.  All of the sensors in my home direct their metric data to a web service or a simple TCP Socket which are listening within Node-Red.   From Node-Red, the data can be directed to various destinations such as a data store, a chart, an actuator such as a relay, a light switch, an alerting system, or even a controller for central heating and cooling.  These definitions are called flows and are store on disk in JSON format.

Node-Red is built on Node.js (based on Javascript) and the BeagleBone Debian Image comes with that pre-installed.  The best way to get Node-Red installed is to follow the instructions for BeagleBone Black on the Node-Red web site:

If you’d like to use a Raspberry Pi instead of BeagleBone Black you can look at a specialized distro called TheThingBox –  It is an OS image pre-loaded with Node-Red.

Node-Red Flows

A Node-Red flow is a definition of a collection of nodes modules which are strung together in Node-Red.  You can read about flows on the Node-RED site here.  and see a sampling of available nodes and flows on the Node-RED web site.  You can find some of my flows on Github.

Charting and Analytics Server

This device is an Odroid C1 running Ubuntu 14.04.  It’s basically a Raspberry Pi clone with a quad core CPU and 1G of RAM.  It can run from a MicroSD as the other micro-computers or, it can run significantly faster ( and significantly more expensively) on an eMMC memory card.  You can purchase these devices in the US from a company called

I have utilized this server to host our data storage and to provide our charting and analysis services.  For that I use Graphite, a python based Django web application which includes a TCP socket listener, named Carbon, for all the data input and a round robin database (RRD) known as Whisper.  Graphite at its core is a capable charting application but it looks kind of dry.  To see cool looking charts with an easy to design web interface I use Grafana.



Graphite Chart Style

Grafana Chart Style

Graphite is a comprehensive application and it has a bunch of moving parts.  The basic process of setting this up is to install Graphite the various supporting components:

  • Carbon, the TCP Socket listener for all the data
  • Whisper – the round robin database
  • Graphite – the web application runs in Apache and has these prerequisites:

You can read the Graphite install instructions here.



Grafana Chart Style

Next comes Grafana.  It is a fork of a component that comes with an application known as ELK (Elasticsearch, Logstash. Kibana).  I’ll let you figure out from which component it is derived.

When I originally installed Grafana it was with version 1.8 and it required the addition of Elasticsearch and Java.  Version 2.x does not have the Elasticsearch/Java requirement so I would recommend 2.x.  You can read about installing Grafana here.  The simple approach requires 3 commands:

# wget
# sudo apt-get install adduser libfontconfig
# sudo dpkg -i grafana_2.1.2.deb

Wifi Controlled Light (LED)

This setup uses an ESP8266 wi-fi device as a web server which is waiting for a URL web service request that toggles an LED on/off.  Of course the LED stands in for a relay or anything you’d like to switch on and off. You can find the code I used here.esp8266_LED_Controller

Here’s the Fritzing breadboard diagram.

What’s Next?

From here going forward, I’ve got some more projects to work on. One is to have all the system events logged and to have a voice system that announces the events; kitchen light on, garage door opened, and so on.  It’s a precursor  to a voice control system.  I’d like to set up a wall switch replacement that contains environmental sensors (temp, humidity, light, presence) and capacitor touch switches for a simple control surface.  I’d also like to manage conditioned air to each room in the house based on metrics received from the wall plate sensors in each room.  In other words it would look like a dozen very inexpensive thermostats distributed all around the house and controlling the air conditioning on a room to room basis.

If you get here and find this article meaningful but find something I could improve upon, please let me know.  Thanks.

Maker Faire 2012

Come visit us at Maker Faire!

I just got the confirmation email that I’ve been accepted to have a booth at this year’s Maker Faire.  The booth is called A Sense of Things, as it was last year, and is numbered 7443.   I hope to visit with all my sensor friends on Saturday and Sunday, May 19th, 20th.

I’ll be showing our latest development on a low cost wireless sensor network designed for the “everyman” or “everywoman” who wants to track things in and around their homes.  Please stop by for a visit.

To sign up for the maker Faire:


Maker Faire Surprise

On the drive to Maker Faire on Friday, I had a few dark moments wondering if anyone would really care about the work I’ve been doing on wireless sensor networks.  I imagine that there are all these sensors struggling to be heard and I’ve been constructing a platform to help facilitate that.  But would anyone share that vision?   On I drove…

My friend, Terence, helped get us set up with the booth and finally with no hope of getting any internet access (seems it was over-taxed most of the time), we retired to the Friday evening’s beer and paella dinner.  We met a lot of wonderfully creative Makers.  The Maker Faire is such a wonderful collection of creativity in all it’s myriad forms.  It is inspirational and gives me hope.  Terence made a good point that Obama should have come to the Maker Faire to see an example of what makes America great.

Well I have to say I was very surprised to see how many people came to our booth to learn about wireless sensor networks.  I’m exhausted and my voice is shot but I feel very satisfied to see so much interest in what we have built.  Thanks to all who came by the booth.  I hope that this experience can be the beginning of an exchange of ideas to make more robust sensor networks that can provide meaning to those who seek to extend what we can know about the world around us.  I heard so many great ideas and I hope we can keep the them coming.

Now that the Maker Faire is over, I plan to focus on this web site for the next couple of weeks and get the tutorials in order.  I’ve started some of them and have not yet published some others.  I promised everyone who I spoke with at the Maker Faire to get these completed and that’s where I’ll be focused.  If anyone wants info about any particular part of the platform, sooner than later, please let me know and I’ll be happy to move that to the front of the line.

Thanks to all who came by the booth, to Terence, to my friends who’ve been supporting my efforts to Make my vision, to Aurora for putting up with my project clutter, and thanks to the folks at Maker Faire for putting on a great show.

(the original post about Maker Faire)

OSHW – Open Source Hardware

I support the Open Source Hardware Definition v1.0

A cool new logo has been defined for Open Source Hardware (OSHW).

Here are the principles of what is being attempted in open source hardware (from the site):

Open source hardware is hardware whose design is made publicly available so that anyone can study, modify, distribute, make, and sell the design or hardware based on that design. The hardware’s source, the design from which it is made, is available in the preferred format for making modifications to it.  Ideally, open source hardware uses readily-available components and materials, standard processes, open infrastructure, unrestricted content, and open-source design tools to maximize the ability of individuals to make and use hardware. Open source hardware gives people the freedom to control their technology while sharing knowledge and encouraging commerce through the open exchange of designs.

Read more here…

Maker Faire! May 21, 22

There was a call for Makers, I applied and got accepted. So this year, instead of being in the stands, I’ll be out on the field having fun. My booth will be called The Sense of Things, as a play on the concept of The Internet of Things.

I will be showing what I’ve learned in the last year regarding wireless sensor networks.

Short Description: Wireless sensor networks, data acquisition and analysis; a discussion about building wireless sensor networks based on open source software and hardware (OSHW) for use in things like home energy, air quality, and elder care.

Long Description: Exploring sensor networks, data acquisition and displaying data.

This project will demonstrate what I have learned in the last year from others on the internet. Open source software has lead to open source hardware (OSHW) and makes it possible to build wireless sensors, open source wireless gateways, data logging data services and charting applications.

With this kind of system we can monitor things like energy used in a home, indoor/outdoor temperatures, wind speed, dangerous gases, the presence of a person in a room, etc.

We will discuss how various online tutorials and technologies (Tweetawatt, xBee, Asus wifi with OpenWRT, data logger, web services, Pachube, Adafruit, MightyOhm, etc) were used to develop the test system.

Web site:

Please come by for a visit.

Saturday, May 21st – SHOWTIME :  10 a.m. – 8 p.m.
Sunday, May 22nd – SHOWTIME:  10 a.m. – 6 p.m.


Wireless Sensor Networks

This is going to be a base post (I’ll make it sticky) to hold the outline of tutorials related to various aspect of wireless sensor networks.  From the sensors and radios, to a gateway,  to web services, data logging and eventually, charting and analysis.  Look at this overview of Wireless Sensor Networks on Wikipedia.

Our interest is in developing a wireless sensor network platform that is inexpensive and simple to use.  There is a sweet spot between super high tech and older outdated technology where we believe there exists a meaningful set of technologies that will fit our goals.

XBee, Wifi, Sensors

XBee, Wifi, Sensors

What we’ve discovered is that we can use radios, like the xBee radios from Digi, with up to 4 sensors hooked up to each one, as our remote sensor boards.  We have also discovered that we can transform a wifi router into a tiny, low powered computer running an embedded, open source, operating system called OpenWRT.  Many wifi routers have a serial port available on the main pcb inside the device to which we can hook up a coordinating xBee radio; the counterpart to the ones on each sensor board.  Then we install a scripting language, Python, into the Linux operating system.  Finally, we install python scripts which can be used to collect the data being transmitted from the sensor boards and send that data to web services like Cosm (formerly Pachube), ThingSpeak,, Paraimpu, etc.

So we have wireless sensor boards sending sensor data to a radio wired into the serial  port of a wifi router.  The wifi router has been re-flashed with an open source embedded Linux operating system, OpenWRT, and to that we’ve added Python as an easy to use scripting language.  We have then added various scripts to bundle the incoming data and send it to the internet for further processing, charting, and so forth.

It is an inexpensive, flexible, easy to use, wireless sensor network platform.

In this ongoing quest to learn more about sensor networks I’ll add links to the Resources Page.


Here’s a list of notes we’ll be updating with information about how to build you’re own wireless sensor network.

  • WSN: Sensors: this is where is all begins.  The sensor responds to some environmental events and generates a voltage or a digital signal.  I’ll be going over a few sensor types that I’ve built; Tweet-a-watt, Temperature, Gas (example of indoor air quality), and a Force Sensitive Resistor (FSR) as an example of Elder Care.
  • Radio: XBee – Radios allow us to create the wireless part of sensor networks.  The XBee radio is very accessible to beginners even if configuration is a bit challenging.  I’ll describe the various aspects of XBee radios that I’ve used.
  • Gateway: Wifi Router – in the original design for the Tweet-a-watt the output from the sensor’s transmitter sent data to an XBee receiver hooked into a PC (via FTDI-USB).  The approach I describe uses a low powered (about 4 watts) Asus wi-fi router in place of a PC.  I’ll describe using OpenWRT as a replacement OS and adding a USB memory stick to extend the storage memory of the device.  I’ll also show how I added python with web service calls in order to send data to the internet.
  • Client facing site: a site for users to register their gateway devices and manage the sensors associated with each.  Also the place to look at the charts and subsequent analysis for the sensor data.  This is an MVC web application written in C# and ASP.NET using Visual Studio 2010 Express and SQL Server 2008 Express.

Next: WSN: Sensors