Posts with «capacitive sensor» label

StarMAT greets visitors with the Imperial March

Strong is the Force, with this Padawan. To coincide with the latest installment of the continuing saga from a galaxy far, far away, [Rohit Gupta] built a Star-Wars themed interactive doormat. The doormat detects a footstep using capacitive sensing and plays a random Star Wars audio clip like the opening theme or the Imperial March or a famous phrase from the movie. Check out the video below the break.

The current setup is temporarily breadboarded, but we are sure it will be popular enough with his visitors to make him tidy it up. The hardware consists of an Arduino with an audio shield connected to a pair of speakers. A capacitive wire loop under the mat and a capacitive sensor tuned to the mat size wire take care of the sensing.

When Earth people step on the mat, the sensor triggers the Arduino to play a random audio clip from the SD card. The capacitive sensing is taken care by the TP223 1-key touch pad detector chip (PDF), which he mounted on a home etched board with SMD parts. The whole bundle is powered by a small “power bank” battery pack like the ones used to charge mobile phones.

Filed under: Arduino Hacks

DIY Connected objects for happy connected people

What happens when a creative technologist wants his family to know he’s thinking about them? He creates a project with Arduino Yún! IMissYou is a simple project transforming a picture in a connected object thanks to a capacitive layer made with Bareconductive Paint and inserted behind the photo. The ‘touch’ is detected by the Arduino through the glass of the frame by a spike in the values (with a basic Capsense library), sent to the internet via wi-fi and delivered to a phone with Pushover.

Martin Hollywood, the Arduino user who made  the project, wrote us:

Looking at the photograph of my family that I have on my desk one day, I missed them and wanted to be home. I touched the photo and realised that somewhere between those was the germ of the idea…

I wanted my family to know I was thinking of them, but I didn’t want to create two products; think GoodNight Lamp – I do love that project. In any case, there was no guarantee they would even notice a ‘blinking’ photo frame responding to my signal. Making the Receive a PUSH notification seemed like a no brainer, but the last time I developed for mobile was iOS 1! There are a number of service apps out there: Pusher, Pushingbox but I decided on Pushover. It had a 7 day trial period and good API support (I’ve since bought a license).

Take a look at his blog for more details and if you want to give him some tips to make it a real product.

Mobile chicken coop includes wireless sensors

In and of itself this mobile chicken coop is a pretty nice build. There are some additional features lurking inside which you don’t find on most coops. [Neuromancer2701] built-in a set of sensors which can be accessed wirelessly. It makes it a snap to check up on the comfort of the hens without leaving the couch.

At the heart of the sensor system is an Arduino along with an Xbee module. The build isn’t quite finished yet, but so far three sensors have been implemented. A thermistor is used to read the temperature inside the coop. To make sure there’s enough water, two sheets of foil tape were applied to the water reservoir. The CapSense library measures the capacitance between these plates which correlates to the water lever (we’ve seen this type of water level sensor before). And finally, there’s a sensor that can tell if the door to the coop is open or shut.

He’s having trouble automating the door itself. This can be pretty tricky, especially if you go for a super complicated locking mechanism like this one.

Filed under: home hacks

Touché with Arduino

Touché is a capacitive-sensing technology, developed by Walt Disney Research, which aims at providing touch and gesture sensitivity to a great variety of objects. From this research paper:

The technology is  scalable, i.e., the same sensor is equally effective for a pencil, a doorknob, a mobile phone or a table. Gesture recognition also scales with objects: a Touché enhanced doorknob can capture the configuration of fingers touching it, while a table can track the posture of the entire user.
The technique behind Touché is known as Swept Frequency Capacitive Sensing (SFCS): at a glance, by monitoring the capacitive response of an object over a specific range of frequencies (instead of a single one), it is possible to infer about its interaction with the outside world.
In his blog, Dzl describes his personal approach toward the development of a system capable to emulate Touché’s behavior with Arduino. Currently, the project is still in a early stage, but improvements and further developments are expected soon.
More information can be found here.


Arduino-based theremin

Theremin is one of the most exiting musical instruments ever made, mainly because of its “quite odd” playing method. Infact, its working principle is based on near-filed coupling between the hands of the theremin player and two metal antennas, used to determine the pitch of a variable-frequency oscillator and to adjust the volume of the output signal, respectively.
Several theremin implementation are possible, such as the “original” analog one (based on the mixing of two sine waves originated by a fixed-frequency oscillator and a variable-frequency one) and those based on digital techniques.
LabIII guys implemented a nice and simple Arduino theremin module, based on a TTL LC-type oscillator, usable not only to play electronic music, but also as a generic sensing-device, for example to control motors and/or to work with Processing, Max etc.
The detailed description of the project, together with schematics and source code, can be found here.



Arduino Blog 21 May 19:29