Arduino Library for Scratch Sensor Board Emulation

I re-wrote the simple sketch as an Arduino Library for Scratch Sensor Board (picoboard) emulation.

You can download it at github

Unzip the contents of this repository into a directory called ScratchSensors in the Arduino libraries directory (or in Sketchbook/libraries)

In your sketch: 

#include <ScratchSensors.h>

and then: 

ScratchSensors Scratchboard;

In Setup: 

Scratchboard.init();

Sensor values are stored in an array internally to the ScratchSensors class called 

Values[];

The picoboard/Scratch sensor board that is emulated has specific sensor labels that are reported:

#define RESISTA 0
#define RESISTB 1
#define RESISTC 2
#define RESISTD 3
#define SLIDER 4
#define LIGHT 5
#define SOUND 6
#define BUTTON 7

Values should be between 0 and 1023. These are scaled by scratch to be between 0 and 100. BUTTON is handled in a special way: 0 is depressed and 1023 is not pressed. Let’s say you have an analog sensor like an accelerometer connected to Arduino pins A0, A1, and A2. Then during loop():

Scratchboard.Values[RESISTA] = analogRead(A0);
Scratchboard.Values[RESISTB] = analogRead(A1);
Scratchboard.Values[RESISTC] = analogRead(A2);

then, write the packets out to the serial/usb port: 

Scratchboard.report();

There’s an example in the examples directory based on the Sparkfun midi shield. It has two pots and three buttons. Of course only one of the buttons can be used with the Scratch buttonpressed semantics, but the others can be tested for specific values.

About The Author

Kevin Osborn

I’m currently the Director of Research and Commercial Development for Radiation Monitoring Devices. By day I research augmented reality systems. I also love to create art, hack electronics and do geeky activities with my kids.

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Author his web sitehttp://baldwisdom.com

21

05 2012

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