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 How does TouchPanel Work

Touch Panel is an overlay to your NXT screen andprovides coordinates of the point where you touch

the stylus.

The Touch Panel is continuously reading for Stylus

presses. Whenever you need, your program can read from the sensor and

receive the coordinates of the stylus location.It is recommended that you use a Stylus (similar to one used for Nintendo

DS). In absence of stylus a Technic Axle also works well (Pick the longest so you can hold it better).

Connections and Placement

Mounting Touch Panel on your contraption

Attach two ‘Technic Axle Joiner Perpendicular 3L with 4

Pins' (48989)’ (as shown in adjacent picture) to your NXT 

on both sides of NXT screen.

Insert three blue ‘Technic Axle Pin

with Friction’ (shown here). PlaceTouch Panel over the NXT Screen and secure in

the blue pins.

Connect Touch Panel to Port 3 of your NXT by using built-in cable.

Programming Techniques

NOTE: Ensure to use latest firmware on your NXT.

NXT-G:

Download the NXT-G blocks available in the NXT-G Blocks

Repository at Mindsensor’s website, at following location:

http://www.mindsensors.com/index.php?

module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=186

Also download sample programs from following location, and modify to suit

 your needs.

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TouchPanelUser Guide

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http://www.mindsensors.com/index.php?

module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=187

NOTE: Gesture data is not available through NXT-G block (The data is a two

dimensional array and there is no direct support for Arrays in NXT-G). If you intend to use Gesture data from the NXTTouchPanel, we suggest you to

use NXC.

NXC:

Download the sample programs and library file available at following location,

and include the library file it in your program by #include directive as:

 #include “TP-lib.nxc”

Alternately, you can modify the sample programs to suite your needs.

http://www.mindsensors.com/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Docu

ment_id=183

I2C Registers:

The Touch Panel appears as a set of registers as follows:

Register Read Write

0x42 X coordinate of current

Stylus touch

-

0x43 Y coordinate of currentStylus touch

-

0x44 Button Presses (one bit for

each button)

Calibration data

0x45 X Coordinate of NXT LCD

Point 1

Also available for writing.

0x46 Y Coordinate of NXT LCD

Point 1

Also available for writing.

0x47 X Coordinate of Touch Panel

Point 1

Also available for writing.

0x48 Y Coordinate of Touch PanelPoint 1 Also available for writing.

0x49 X Coordinate of NXT LCDPoint 2

Also available for writing.

0x4a Y Coordinate of NXT LCD

Point 2

Also available for writing.

0x4b X Coordinate of Touch PanelPoint 2

Also available for writing.

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0x4c Y Coordinate of Touch Panel

Point 2

Also available for writing.

Gesture data **

0x4d Size of available data -

0x4e X coordinate of next point -

0x4f Y coordinate of next point -** The Gesture data is a rolling buffer at position 0x4e and 0x4f, read

these locations repeatedly until end of available data. Note that, you shouldread both these locations (X & Y) in a single read operation.

Current Consumption

Average measured current consumption of this device is: 1 mA

I2C Bus address

Factory Default Address: 0x04.

This I2C address can not be changed.

Supported Commands

Command Function

B Change mode to calibrated readings (this is also

default mode)

C Commit the calibrations data to permanent memory.

U Change mode to Un-calibrated readings.

F Restore Touch Panel to Factory Calibration.1-8 Sampling rate for the Gesture chunks (1 being

fastest, and 8 being slowest, default is 4)

Adding your own Overlay for Keys

For your creative application if you require key marks for the key positions,

 you can add your own overlays.Download Overlay templates, and instructions from following url:

http://www.mindsensors.com/index.php?

module=documents&JAS_DocumentManager_op=viewDocument&JAS_Docum

ent_id=184

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