Page 1 of 7
AT42QT1010 Capacitive Touch Breakout
Hookup Guide
Introduction
If you need to add user input without using a button, then a capacitive touch
interface might be the answer. The AT42QT1010 Capacitive Touch
Breakout offers a single capacitive touch button with easy-to-use digital I/O
pins.
AT42QT1010 Breakout Board
The AT42QT1010 is a dedicated, single-button capacitive sense chip. The
chip handles monitoring a conductive area for touch. As long as a touch
(e.g. from a finger) is detected, the AT42QT1010 keeps the output line high.
Otherwise, the line is kept low. You just need to provide a power source
(1.8V - 5V) and ground for the AT42QT1010 to work. SparkFun’s breakout
board contains an on-board electrode capable of detecting touches.
Additionally, a PAD pin is available if you would like to create your own
external electrode.
Covered In This Tutorial
This tutorial will show you how to connect the AT42QT1010 Breakout Board
to an Arduino along with some example code to read the board’s output.
Additionally, alternative ways to use the board will be shown, such as
mounting it to an acrylic panel and creating your own capacitive sensing
pad.
Page 2 of 7
Required Materials
• AT42QT1010 Capacitive Touch Breakout Board
• Arduino, RedBoard or any Arduino-compatible board.
• 4-Pin Male SMD header or Male PTH headers to make the board
breadboard compatible.
• Jumper wires to connect from breadboard to Arduino.
• Breadboard to tie everything together.
Suggested Reading
•
•
•
•
•
•
What is an Arduino?
How to Solder
Working with Wire
Switch Basics
Capacitors
LEDs
Board Overview
If we look at the front of the board, we see a large, circular pad (the
“electrode”) and several pins. The on-board electrode will detect touches
when pressed with a finger as long as the board is powered.
AT42QT1010 Breakout front
GND
should be connected to the ground of the host circuit.
OUT
is the output of the AT42QT1010. HIGH on touch, LOW otherwise.
VDD
is the power supply for the AT42QT1010 and needs to be connected
to a voltage between 1.8V - 5V.
LED
controls the operation of the on-board LED. By default, it is connected
to the OUT pin. If you de-solder the “LED Enable” jumper on the back side,
you can independently control the LED.
PAD
is located in the upper-left corner and allows you to connect to an
external electrode. Note that there is a small surface mount pad on the
back side by the PAD pin hole. If you want to mount the board flush, you
can solder a wire directly to the surface mount pad.
How It Works
Take a look at the back side of the board.
Page 3 of 7
AT42QT1010 Breakout back
The AT42QT1010 chip is located on the right side of the board. It uses a
resistor and a capacitor network to adjust the sensitivity of the electrode.
High frequency pulses are sent to the pad. When a fleshy object (such as a
finger) approaches the pad, it acts like a very small capacitor and changes
the shape of the pulses. When the AT42QT1010 detects these slight
changes, it raises the OUT line to HIGH, indicating a touch is present. Once
the pulses return to normal (i.e. the fleshy object is moved away from the
pad), the AT42QT1010 drives the OUT line LOW.
LED Enable
The output from the AT42QT1010 goes directly to the OUT pin on the
board as well as to the transistor (left side), which operates the LED (center
of board). By default, the OUT line and LED lines are connected, which
means that on a touch, the on-board LED lights up. You can disconnect the
LED by de-soldering the jumper labeled “LED Enable.” This will cause the
LED to no longer light up on a touch, but you can still drive the LED using
the LED pin on the board.
Mode
On the right side of the board, you will also notice a jumper labeled “Mode”
with “L” and “F” markers. By default, the center pad and the “F” pad are
connected, which puts the AT42QT1010 in “Fast” mode. In Fast mode, the
chip is more responsive to touch events but draws 200µA - 750µA in normal
operation. If you de-solder this jumper and connect the center pad to the “L”
pad, the AT42QT1010 will be in “Low Power” mode. In this mode, the chip
is slightly less responsive to events but only uses 15µA - 75µA.
Hookup Example
Assembly
If you are not planning to mount the board flush to a panel, you can solder
either wires or break away headers to the 4 header holes on the board.
Page 4 of 7
PTH headers are recommended if you are using a breadboard.
On the other hand, if you wish to mount the AT42QT1010 to a panel, you
can solder a 4-pin male header to the SMD pads.
SMD headers work better if you plan to mount the board to a panel
Connecting the AT42QT1010 Breakout Board
Basic hookup using an Arduino and a breadboard
For an Arduino, make the following connections with jumper wires:
(AT42QT1010
→
Arduino)
• VDD
→
5V
• OUT
→
2
• GND
→
GND
Mounting the AT42QT1010 Breakout Board
One advantage of capacitive touch boards is their ability to be mounted to
panels and detect touch through thin plastic, cardboard, etc. Using a drill or
laser cutter, cut four 0.125 inch holes in the same pattern as the mounting
holes on the breakout board.
Attach the board to the panel using #4-40 screws and #4-40 nuts.
The AT42QT1010 will detect touch through 0.125 inch acrylic
External Electrode
Page 5 of 7
You can create your own electrode by using foil, copper tape, or any other
conductive material. Cut or shape the electrode and attach a wire between
the electrode and the PAD pin on the AT42QT1010 breakout board. The
electrode can be almost any shape and size.
Touch can be detected on external electrodes
Example Code
Open the Arduino program and paste the following code into the sketch:
FPGA/CPLD
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
