Demand Peripherals     Robotics and Automation Made Easy

TOUCH4: Quad Touch Interface Card

The TOUCH4 card works with a Baseboard FPGA card to capture touch events on its four input pads.


- Senses touch events on four inputs
- Simple, low cost design
- Uses external pads or pads printed on the card
- Driver automatically adjusts to changes in stray capacitance
- Driver lets you set the sensitivity

The TOUCH4 card and matching FPGA peripheral monitors four pads for touch events. Each touch pad controls the frequency of an RC oscillator. Touching a pad changes the capacitance of the circuit and changes the frequency. The FPGA peripheral accurately measures the four oscillator frequencies and reports them to the dpdaemon host where changes in frequency are reported as touch events.

Solder pads allow the addition of external touch pads.



The schematic and layout of the TOUCH4 are shown below. The Eagle schematic file is available here: touch4.sch and touch4.brd. The bill-of-materials file is available here: touch4.txt.



FPGA Defined Peripherals
User Interface
FPGA Configuration
FPGA Buttons & LEDs
Host Tx/Rx Interface
AVR Interface
Stereo Audio Amplifier
Text LCD and Keypad
Quad WS2812 Interface
Quad Slide Pot
IR Recv/Xmit
6 Digit LCD
RC Decoder
Keyfob RF Decoder
Rotary Encoder Interface
Quad Touch Interface
Motion Control
Dual DC Motor Controller
Dual Quadrature Decoder
Quad 13 Bit Servo
Bipolar Stepper Controller
Unipolar Stepper Controller
Simple Input / Output
Quad Binary Output
Quad Binary Input
Octal Input/Output
32 Channel Binary Output
32 Channel Binary Input
Quad Serial Output
Octal Serial Output
Octal 12-bit ADC
Quad Ping))) Interface
Pololu QTR Interface
Octal SRF04 Interface
Generic I2C
Generic SPI
Octal 8-Bit DAC
Quad Digital Potentiometer
Quad PWM Output
Quad PWM Input
Quad Event Counter
Real Time Clock
Dual Pulse Generator

Interface Cards
Control Cards
User Interface
Stereo Audio Amplifier
IR Recv/xmit
Six Digit LCD Display
Keyfob RF Receiver
Rotary Encoder
Quad Switch Card
Text LCD / keypad
Quad Slide Pot
Quad Touch Interface
Motion Control
Dual 7-amp H-bridge
Quad Open Drain Driver
Quad 10 Amp Relay Card
Input / Output
Octal 8-Bit DAC
Quad Digital Potentiometer
Octal 12-bit ADC
Octal SRF04
I2C Prototyping
SPI Prototyping
USB 2.0 Hub
Real Time Clock
Octal Input/Output
32 Channel Input
32 Channel Output
Power Distribution Card
15 Amp Power Distribution
5 Volt Switching Regulator
ATX Power Break-Out Card
Disk Drive Power Break-Out
MP43 Aluminum Mounting Plate
WW4 Large Prototyping Card
WW2 Prototyping Card
WW1 Small Prototyping Card
SMP SMD Prototyping Card