Capacitive sensing is how your phone’s touch screen works — basically detecting the natural charge in a person’s body on the screen.
I’ve seen Team Blinky friend Liza Stark play and build simple touch sensors using the same technique with Arduino, so this week I gave it a try.
My goal: Use a touch sensor instead of a button on the Monthly Mood Cube.
It turns out to be pretty easy.
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 data.sparkfun.com.
Here are the steps as things stand now:
- The sensor reads the data (as in my original post).
- The Ardunio formats a message and texts it with a Fona (wiring details here, updated code here).
- Instead of texting to Twitter, it now texts to a phone number I bought at Twilio for $1/month.
- 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).
- 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.
This week I used it to drive lights and motors on a table. And it was surprisingly easy.
In just a few weeks, a class of journalism students will be wading into West Virginia streams to deploy water sensors.
They’ll be sensing water conductivity over several weeks using a cool, Arduino-like board called Riffle.
But the crux of the system is a simple circuit I tried for the first time tonight.
Texting is something I love playing with, and I’ve always wanted to make a sensor-bot that skipped the hassle of wifi by texting me its data.
So this week, I tried to make some progress on that by making a texting bot.
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.
Visualizing one’s heartbeat is just cool. I’ve been into the idea since I learned that signals sent by the Polar heart monitor straps joggers use can be detected with a cheap device.
I’ve made a heartbeat hoodie, which was a lot of fun. But in the end, a bright, flashing sweatshirt starts to annoy the people around you. Now I’m working toward a more wearable wearable, one that changes subtly as my heart beats faster or slower.
This week I took a step on the way to that wearable by getting three LEDs — blue, green and yellow — to light up according to my heart rate. A calm heartbeat and blue glows, a little faster and you get green and really fast lights the yellow one.