Make Every Week: Message From a Bottle

A summer of tinkering has culminated with a conductivity and temperature sensor that texts its data from inside a Gatorade bottle.

The contraption consists of a Riffle, which is an Arduino-like board designed to fit through the mouth of a water bottle and a Fona cell-phone board. And a bottle.

The plan is to submerge several of these along a stretch of the Monongahela River as part of a sensor-journalism class at West Virginia University. It’s a work in progress, but you can [see how things are going]. My job was to build a working conductivity sensor that would report its findings live. Here are the components and how I made it go.

Update: We actually deployed some of these sensors in a river!

Make Every Week: Temp -> Text -> Table

Texting temperature data to Twitter is fun, but more useful is sending that information to a table.

That’s what I did this week, as my wanderings into wireless data collection continue: Post the temperature and humidity from my little experiment to a table at

Here are the steps as things stand now:

  1. The sensor reads the data (as in my original post).
  2. The Ardunio formats a message and texts it with a Fona (wiring details here, updated code here).
  3. Instead of texting to Twitter, it now texts to a phone number I bought at Twilio for $1/month.
  4. Twilio then relays that data to my project server in the Amazon cloud as an http “POST” (deets on setting up a cloud server here).
  5. My project server parses the text message, composes a URL with the data, and hits the Sparkfun open data system with that URL (code for that is here).

This all happens in just a few seconds, every 20 minutes.

Make Every Week: Circuit Boards, For Reals

I always considered circuit boards like this something you bought, not something you made.

Not any more.

I actually helped to make the board in the picture above. And it was awesome fun.

The board is designed to monitor the conductivity (and, possibly, contamination) of water in lakes and streams, with the wonderful feature that it fits through the mouth of a regular water bottle. It’s called Riffle and it is the brainchild of Don Blair, who’s working with Public Lab and the MIT Center for Civic Media. This week I had the honor of working with Don at MIT.