TCP/IP - Multi Touch Bricklet

This is the description of the TCP/IP protocol for the Multi Touch Bricklet. General information and technical specifications for the Multi Touch Bricklet are summarized in its hardware description.

API

A general description of the TCP/IP protocol structure can be found here.

Basic Functions

BrickletMultiTouch.get_touch_state
Function ID:

1

Request:

empty payload

Response:
  • state -- uint16

Returns the current touch state. The state is given as a bitfield.

Bits 0 to 11 represent the 12 electrodes and bit 12 represents the proximity.

If an electrode is touched, the corresponding bit is true. If a hand or similar is in proximity to the electrodes, bit 12 is true.

Example: The state 4103 = 0x1007 = 0b1000000000111 means that electrodes 0, 1 and 2 are touched and that something is in the proximity of the electrodes.

The proximity is activated with a distance of 1-2cm. An electrode is already counted as touched if a finger is nearly touching the electrode. This means that you can put a piece of paper or foil or similar on top of a electrode to build a touch panel with a professional look.

BrickletMultiTouch.recalibrate
Function ID:2
Request:empty payload
Response:no response

Recalibrates the electrodes. Call this function whenever you changed or moved you electrodes.

BrickletMultiTouch.set_electrode_config
Function ID:

3

Request:
  • enabled_electrodes -- uint16
Response:

no response

Enables/disables electrodes with a bitfield (see get_touch_state).

True enables the electrode, false disables the electrode. A disabled electrode will always return false as its state. If you don't need all electrodes you can disable the electrodes that are not needed.

It is recommended that you disable the proximity bit (bit 12) if the proximity feature is not needed. This will reduce the amount of traffic that is produced by the CALLBACK_TOUCH_STATE callback.

Disabling electrodes will also reduce power consumption.

Default: 8191 = 0x1FFF = 0b1111111111111 (all electrodes enabled)

BrickletMultiTouch.get_electrode_config
Function ID:

4

Request:

empty payload

Response:
  • enabled_electrodes -- uint16

Returns the electrode configuration, as set by set_electrode_config.

BrickletMultiTouch.set_electrode_sensitivity
Function ID:

6

Request:
  • sensitivity -- uint8
Response:

no response

Sets the sensitivity of the electrodes. An electrode with a high sensitivity will register a touch earlier then an electrode with a low sensitivity.

If you build a big electrode you might need to decrease the sensitivity, since the area that can be charged will get bigger. If you want to be able to activate an electrode from further away you need to increase the sensitivity.

After a new sensitivity is set, you likely want to call recalibrate to calibrate the electrodes with the newly defined sensitivity.

The valid sensitivity value range is 5-201.

The default sensitivity value is 181.

BrickletMultiTouch.get_electrode_sensitivity
Function ID:

7

Request:

empty payload

Response:
  • sensitivity -- uint8

Returns the current sensitivity, as set by set_electrode_sensitivity.

Advanced Functions

BrickletMultiTouch.get_identity
Function ID:

255

Request:

empty payload

Response:
  • uid -- char[8]
  • connected_uid -- char[8]
  • position -- char
  • hardware_version -- uint8[3]
  • firmware_version -- uint8[3]
  • device_identifier -- uint16

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here

Callbacks

BrickletMultiTouch.CALLBACK_TOUCH_STATE
Function ID:

5

Response:
  • state -- uint16

Returns the current touch state, see get_touch_state for information about the state.

This callback is triggered every time the touch state changes.