SingleTact SingleTact Standard Manuel utilisateur
USER MANUAL
EXPERIENCE
INCREDIBLE
PERFORMANCE
V2.3
pg. 2
Copyright © 2017- www.SingleTact.com
CONTENTS
1INTRODUCTION............................................................................................................................................... 3
2INTERFACE DESIGN ......................................................................................................................................... 4
2.1 Connectivity.............................................................................................................................................. 5
2.2 Analog Interface....................................................................................................................................... 6
2.3 I2C Interface.............................................................................................................................................. 7
2.4 I2C Operations ........................................................................................................................................ 10
2.4.1 I2C Write Operation ........................................................................................................................ 10
2.4.2 I2C Read Request Operation ........................................................................................................... 11
2.4.3 I2C Read Operation.......................................................................................................................... 11
2.5 Conversion Detail ................................................................................................................................... 13
2.6 Product Categories................................................................................................................................. 14
3TROUBLESHOOTING SingleTact .................................................................................................................... 15
3.1 Arduino UNO not detected by PC. ......................................................................................................... 16
3.2 Invalid setting error on PC (Popup reports” Failed to set”)................................................................... 16
3.3 No Analog output (remains at 0V). ........................................................................................................ 16
3.4 Analog output stays at 0.5V. .................................................................................................................. 16
4EXAMPLE USE CASE....................................................................................................................................... 17
4.1 PC and Arduino Example........................................................................................................................ 18
4.2 Programming the Arduino UNO with SingleTact Example..................................................................... 20
4.3 Arduino Demo Outline ........................................................................................................................... 22
4.4 Example .NET API ................................................................................................................................... 26
5Resources...................................................................................................................................................... 27
6Glossary......................................................................................................................................................... 28
7Revision History ............................................................................................................................................ 29
pg. 3
Copyright © 2017- www.SingleTact.com
1INTRODUCTION
SingleTact is a single element tactile pressure sensor that accurately and reliably quantifies applied
force combined with a simple interface board offering a 0 to 2V analog output for immediate Data
Acquisition (DAQ) integration and an I2C based interface for integration into embedded systems.
Standard and Calibrated sensors (with matched pre-calibrated interface board) are available.
This document provides all the information necessary to interface with the SingleTact including a
sample Arduino digital interface and simple C# PC DAQ software (see EXAMPLE USE CASE)
All demo and API source code is open source and can be downloaded from: www.singletact.com.
Figure 1 SingleTact Sensor and Interface Board
Figure 2 Use Case Configurations
*1 –In addition to the data acquisition example, a .NET library is available to download for simple integration into a user’s
own software suite. See Example .NET API.
*2 –Supports over 100 SingleTact interface boards on a single I2C bus. The interface board firmware can be modified to
fit user’s specific use cases – if required please contact PPS to discuss this option.
*3 –PPS maybe able to assist with this –use the contact links at http://www.singletact.com/contact/.
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MCU
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MCU
Arduino and PC data acquisition
evaluation software
Analogue Out. Connect to multitier,
oscilloscope or data acquisition card
User reads capacitance
using their own circuitry
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UNO
Single Tact.com
I2C Digital Output. Interface to user
electronics
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User
Hardware
Analog
Measurement
I2C
I2C
User
Hardware
pg. 4
Copyright © 2017- www.SingleTact.com
2INTERFACE DESIGN
pg. 5
Copyright © 2017- www.SingleTact.com
2.1 Connectivity
The sensor is plugged into the FFC connector on the green interface board (with the sensor
connector pads facing upward). The connections are outlined in Figure 4.
Electrical parameters are outlined in Table 1.
Figure 3 Sensor Assembly
Figure 4 Interface board header connections
Table 1 Electrical parameters
Parameter
Value
Supply Voltage, Vcc
3.7 –12V
I2C clock frequency
100KHz or 400KHz
I2C bus level
3 –5V
I2C output range (sensor data)
10-bit (Operational FSR output 9-bit)
Analog output range
0 –2V (Operational FSR output 0.5 –1.5V)
Permitted analog output load
>5K
Frame Sync level
3.3V CMOS output
Sensor update rate (I2C or analog)
>140Hz (dependent on settings)
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MCU
Note via orientation
CONNECTION
Reserved
I2C Interface (SDA)
Frame Sync
Ground
1
4
3
2
8
5
6
7
CONNECTION
Reserved
I2C Interface (SCL)
Analog Out
Vcc
PIN
NUMBER
pg. 6
Copyright © 2017- www.SingleTact.com
2.2 Analog Interface
The analog output swings from 0to 2V, with the valid working output ranging from 0.5V to 1.5V as
shown in Figure 5.
As pressure increases beyond the full scale range (FSR) the output will increase to 2V and then limit.
The sensor should be unloaded at power on to allow the sensor’s baseline to be registered correctly.
NOTE: An output below 0.5V may indicate negative pressures, which occur when the sensing area is
under tension. This should be avoided since it can damage the internal structure of the sensor.
NOTE: Sensor over pressure should be limited to less than 3x FSR to avoid damaging the sensor.
Figure 5 Analog Output
OVER
PRESSURE
NEGATIVE
PRESSURE
VALID
RANGE
Force or Pressure
Analog Output
0V
0.5V
1.5V
2.0V
FSR
0
pg. 7
Copyright © 2017- www.SingleTact.com
Figure 6 DAQ Connection Requirements
2.3 I2C Interface
The SingleTact I2C interface supports the standard (100 Kbits/s) clock rate in 7-bit address mode.
The SCL and SDA lines must be pulled up to the bus voltage which can be between 3V and 5V.
Please refer to the I2C specification for bus protocol implementation & pull-up value considerations.
The interface board will always respond to two I2C addresses: 0x04 and the address specified in
flash (register address 0). As shipped the default flash address is also 0x04.
Multiple sensor interfaces may be connected to a single I2C bus. The bus address of individual
sensor interfaces can be configured by writing desired address value (4 to 127) via the I2C interface
to register address 0 with an I2C Write Operation. Change of individual sensor I2C addresses is
supported by the PC and Arduino Example.
NOTE: As the interface board will always respond to address 0x04 then this address must be
considered reserved for SingleTact. Where multiple SingleTact interfaces are to be connected to the
same I2C bus then address 0x04 must be considered invalid and in this use case the configurable
address of all connected SingleTact nodes must be individually changed from the default value before
each SingleTact is added to the multi-node bus.
The SingleTact software architecture is based on a 192 byte register block –see Figure 7 and
Table 2 for details.
All control registers are located in first 112 bytes and get written to NVM when modified (and are
therefore persistent after a power cycle). Configuration registers on Calibrated sensors interfaces are
protected from modification.
The sensor results are available from bytes 128 to 133. As shipped, results are updated at >140Hz
(this is dependent on capacitance sensor settings).
CONNECTION
No Connect
No Connect
No Connect
Ground
1
4
3
2
8
5
6
7
CONNECTION
No Connect
No Connect
Analog Out
Vcc
PIN
NUMBER
pg. 8
Copyright © 2017- www.SingleTact.com
NOTE: It is the Users responsibility not to write to any Reserved locations.
Figure 7 Register Layout
Table 2 Register Details
BYTE
SETTING
0
I2C Address (4-127)
1
User configurable serial number MSB
2
User configurable serial number LSB
3
Reserved
4
Reserved
5
Capacitive Sense (Accumulator) Default 0x04 *1
6
Capacitive Sense (Reference Gain) Default 0x01 *1
7
Reserved
8
Capacitive Sense (Discharge Time) Default 0x03 *1
Control
and
Status
0
111
Output
Sensor Data
128
191
Writes get stored
to Flash
Read Only
pg. 9
Copyright © 2017- www.SingleTact.com
BYTE
SETTING
9
Capacitive Sense (Output Current) Default 0x00 *1
10
Output digital scaling MSB
11
Output digital scaling LSB
12
Number of elements, must be 1
13
Reserved
14
Delimiter –leave as 0xFF
15
First element to scan, set to 0
16-39
Reserved
40
Delimiter –leave as 0xFF
41
Sensor baseline MSB
42
Sensor baseline LSB
43-90
Reserved
91
Delimiter –leave as 0xFF
92-127
Reserved
128
Frame index MSB (increments on each new reading)
129
Frame index LSB (increments on each new reading)
130
Sensor Timestamp MSB (0.1ms increments) *1
131
Sensor Timestamp LSB (0.1ms increments) *1
132
Sensor output MSB
pg. 10
Copyright © 2017- www.SingleTact.com
BYTE
SETTING
133
Sensor output LSB
134 - > 191
Reserved
*1 Should only be used as a coarse estimate as it is subject to drift.
2.4 I2C Operations
I2C SingleTact supports three I2C operations: Write, Read Request and Read.
2.4.1 I2C Write Operation
I2C bus Transfer: Master Write to Slave.
This command writes values to the register block. All writes also update the internal flash memory so
settings are persistent through a power cycle.
Bytes 3 to N-1 (where N is the packet length) contain the data to be written to consecutive registers.
Data may be written to the first 128 bytes (excluding reserved locations).
Writing outside of the valid range will fail.
Configuration registers on Calibrated sensors interfaces are protected from modification.
Table 3 Write Operation Data Packet Format
BYTE
TO SENSOR
0
0x02
1
Write offset in register block
2
Number of bytes to write (1 –28)
3 -> (N-1)
Data to write (1 to 28 bytes)
N (max 31)
0xFF –end of packet delimiter
Ce manuel convient aux modèles suivants
1
Table des matières
