Step-by-step guide to programming the RN-XV WiFi module for Arduino

The Arduino prototyping standard has been around for about 6 years now, and has proven to be immensely useful for sensing devices. It's the heart of the DustDuino and many other sensor nodes.

But for all the flexibility that the Arduino provides for collecting data about the environment, there still isn't a reasonably-priced, reliable shield to send data via WiFi.

The official Arduino WiFi shield, while well-supported, costs around $85. That's a pretty high price to connect a $4.50 chip to a network. Cheaper options such as the WiFly shield do exist, but some of the libraries supporting these devices are difficult to decipher or unstable, if they exist at all.

I spent a long time myself looking for a cheap, effective WiFi solution for the Arduino platform, and I've been very pleased with the $35 RN-XV module.

DustDuino: A plan to crowdsource environmental reporting with low-cost dust sensors

A before and after photo of Shanghai inundated with smog, by Flickr's morgennebel.

There's some good news in the air. Or, well, about the air.

Last month, the American Lung Association released its 2013 report on the quality of the nation's air. The Lung Association's "State of the Air" report shows the country's air is continuing to improve.

The Lung Association attributes healthier air as a "direct result of emissions reductions from the transition to cleaner diesel fuels and engines and coal-fired power plants, especially in the eastern United States."

That much is good. But there's much room for improvement.

According to the report, "Of the 25 cities with the worst problem with spikes in particle pollution, fourteen had more days or worse problems in 2009-2011 than in the previous report." Six cities included in the report had their worst year ever (over the 14 years the report has been made) for short-term spikes in particulates.

Chicago, home to some of the dirtiest coal-fired power plants in the nation, continued to flunk both daily and annual levels of particulate pollution. This was where I did my own environmental investigation on how the Fisk coal-fired power plant threatened the health of the Pilsen neighborhood (see: "Battle in the Barrio").

The Fisk station dumped 755 tons of particulates into the air on an annual basis, according to a pollution report from the Environmental Protection Agency. The Clean Air Task Force found that the plant contributed to 15 deaths and 23 heart attacks annually, a figure based on EPA data.

The residents of Pilsen eventually won their battle, and the Fisk station was closed. EPA tests after the plant closure showed the particulate and radiation levels had returned to city-wide norms. Interestingly, one of the EPA air quality monitors was mounted in a baby stroller to measure levels around the perimeter of the plant.

Pilsen didn't have air quality monitors to begin with, though. Its residents had to lobby the Illinois EPA before the state placed an air monitor atop an elementary school in the neighborhood. The readings from the monitor led the IEPA to declare Pilsen a "nonattainment" zone for lead, a particulate which impairs the IQ, learning capabilities, and memory of children.

Making a home for a sensor node - with a laser.

Sensor nodes need a good home if they're to last any considerable amount of time. And if they're to be deployed outdoors, they need an especially robust home.

This can be complicated. Most sensors need to be exposed to the elements to obtain good readings. But expose these electronics to the elements too much, and you'll break them.

In a pursuit of finding the right balance between price and accuracy for a sensor node for professional and community journalists, I'm fabricating a prototype using open-source hardware and software, 3D printers, and now, lasers. Fortunately the "maker" revolution makes this process more accessible than ever.

Previously I wrote about working with Arduinos and temperature sensors. Continuing on the theme of sensor nodes for journalism, here are some details on the next step in the prototyping process.

Building a Wifi Temperature Node for Journalism

Wireless sensor nodes can help monitor conditions the community, in the next state over, or across the globe. These sensors don't have to be complex or expensive to be useful -- even a simple wireless temperature node can be helpful in tracking heat waves, monitoring the heat-island effect in cities, and serving as a warning system for asthma sufferers.

Previously, I've chosen a prototyping platform and 3D printed useful parts to make a sensor node. This post covers planning, assembling, programming, and testing a wireless temperature sensor node for journalism.

Heat island effect and asthma: an argument for temperature nodes for journalists

Meteorologists shouldn’t be the only people in the news ecosystem concerned with temperature. Extreme temperatures can exacerbate food shortages, hurt the economy, affect energy prices, provoke health crises, cancel public events and disrupt public services.

At the moment, Australia is undergoing the worst heat wave it’s ever recorded. Pavement has melted, and gasoline evaporates right out of the fuel pump, making refueling a car a challenge. Fires are burning out of control in coastal regions. People have died.

It’s gotten so hot (all together now: how hot is it?) that the Australian weather service has added a new color to its heat map which denotes temperatures above 122 degrees Fahrenheit. That’s 50 degrees Celsius, or half the boiling point of water.

This also doesn’t seem like a problem that will disappear in the near future. Climate scientists believe extreme temperatures are only going to be more prevalent. Due to climate change, many parts of the world could experience more extreme high temperatures and fewer extreme low temperatures, with climate models predicting higher maximum temperatures and more heat waves in the future (Easterling et al, 2000).

By some estimates, these heat waves will increase by a factor of 5 to 10 in the next four decades (Barriopedro et al, 2011). Without countermeasures, these high temps could cause “increased adverse health impacts from heat-related mortality, pollution, storm-related fatalities and injuries, and infectious diseases” (Field et all, 2007).

Some might point out that we have a national service that tells us what the temperature is. Election forecasting virtuoso Nate Silver pointed out in his book “The Signal and the Noise” that it’s such a valuable service, in fact, that a multi-billion dollar service industry in weather forecasting has sprung up from the National Weather Service freely sharing its weather data (it should be noted that these services are providing independent forecasts, not simply repackaging NWS data).

In an age where many phones come pre-loaded with weather apps, does it make sense for a publication to have a network of temperature sensors?

Making a sensor node for journalism: picking components and 3D printing useful bits

Open-source microcontrollers can be very handy for journalists: they can fly a data-gathering drone and control a data-gathering sensor node, among other uses. Previously I wrote how sensor nodes could be useful in a journalism investigation. Now it's time to leave the theory behind, and actually prototype one of these sensor nodes.

Nodes for journalists: a primer on bringing sensor data to the reporter

Drones are pretty cool, and could be pretty useful for journalists. They allow journalists to film hard-to-reach spots, such as partially-sunken cruise liners. These unmanned systems also can be used to collect geospatial data and photomaps, both of which can come in handy for a journalism investigation.

As I’ve written before, though, drones simply are remotely piloted aircraft (or watercraft). By themselves, they are not very useful tools. What actually makes them useful is that they are mobile platforms for sensors, which can collect data to guide reportage. Cameras are just one of a multitude of sensors that drones can carry into the sky.

What kind of additional sensors could you use on a drone? It’s probably easier to ask what exactly you want to measure in the environment, and then find a sensor to fit the application.

JournoDrone 2: Learning from the past, Looking to the future

JournoDrone One had an important mission: to be a drone journalism platfom that was "powerful, durable, transportable, affordable, upgradeable and supported by a community of experts." It became a pile of foam instead.

But that's OK. Drone development, especially at this state of technology, is a matter of trial-and-error. That's why myself and fellow DroneJournalism.org developer Acton Gorton are giving it another shot. We are taking all of the experience, knowledge, and goals from the JournoDrone One project and starting again with JournoDrone 2.