Team Punch Through:

Published December 7, 2015 © MIT

LightBlue Sandbox: Trackpad Visualization

Use LightBlue Explorer for iOS to visualize your Bean's data in Bean Sandbox.

BeginnerProtip1,084

LightBlue Sandbox: Trackpad Visualization

Things used in this project

Hardware components

Punch Through LightBlue Bean

Hand tools and fabrication machines

Punch Through LightBlue Explorer for iOS

Story

Introduction

LightBlue Explorer's offers some features that enable you to test devices. However, with the Bean, LightBlue also offers a Sandbox view that can interact with the connected Bean. There are three different ways the Sanbox subviews can interact with the Bean. We will be exploring with the track pad view.

Software

* LightBlue App

* Bean Loader App for iOS

Hardware

* LightBlue Bean

* iOS device

To open the XY trackpad in your LightBlue app:

Connect to a Bean.
Select Options in the upper-right corner.
Select Sandbox View.
Select the second tab on the bottom of the screen:

How the Sketch Works

*Line 2-3: sets the variables for the control IDs

*Line 5: is the setup function. This function is executed only once during the duration of the program.

*Line 9: is the loop function. This function is executed multiple times.

*Line 13-14: gets the x-axis and y-axis. The map function here is taking the low and high ranges for the acceleration.

*Line18-23: Creates a 4-byte long buffer and assign each index to specific values.

*Line24-26: We type cast buffer to an 8-bit long integer and send it over Serial.

High Level Overview of the Sketch

This sketch demonstrates how to send data to a sandbox control. It reads the X and Y axis values from the accelerometer, scales the values to 0-255, and sends them to the trackpad.

For more information on the data format used by Bean Sandbox, check out the Trackpad Control example project.

Troubleshooting

Having trouble with this guide? Reach out to BeanTalk to get directed feedback from our developers and community!

TrackpadVisualization.ino

// Sandbox control IDs
char MSG_XYPAD_X = 8;
char MSG_XYPAD_Y = 9;

void setup() {
  // Bean starts serial automatically; no need to set baud rate
}

void loop() {
  AccelerationReading accel = Bean.getAcceleration();
  // Acceleration values range from -512 to 511
  // Bean Sandbox accepts values from 0 to 255
  uint8_t x_axis = map(accel.xAxis, -512, 511, 0, 255);
  uint8_t y_axis = map(accel.yAxis, -512, 511, 0, 255);

  // Construct two sandbox messages, two bytes each: set X axis, set Y axis
  char buffer[4];
  buffer[0] = MSG_XYPAD_X;
  buffer[1] = x_axis;
  buffer[2] = MSG_XYPAD_Y;
  buffer[3] = y_axis;

  // Write messages to serial and sleep for 50 ms
  uint8_t* buf = reinterpret_cast(buffer)
  Serial.write(buf, 4);
  Bean.sleep(50);
}

Credits

Punch Through

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We’ve been building connected products since 2009. Our diverse team has expertise in every layer from hardware to software to web.

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LightBlue Sandbox: Trackpad Visualization

LightBlue Sandbox: Trackpad Visualization

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

Introduction

How the Sketch Works

High Level Overview of the Sketch

Troubleshooting

Code

TrackpadVisualization.ino

Credits

Punch Through

Comments

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